Video Hosting Support » Streaming Media General Discussion

What is HTTP streaming?

modcam — Mon, 22 Jun 2009 17:27:15 +0000

HTTP Streaming can be several things. Here is an attempt to outline the different HTTP streaming protocols:

MP3/AAC/aacPlus HTTP Streaming:
This is usually the SHOUTcast or Icecast ICY protocol, which uses ADTS packetization over TCP. This is NOT compatible with ANY RTSP streaming. This uses an ICY based Streaming Server such as SHOUTcast or Icecast2. This is the part that is MOST confusing: QuickTime/Darwin Streaming Server includes an ICY server module for MP3 streaming only. It is based the old deprecated Icecast1 protocol, and is no longer supported or recommended. Icecast2 is the preferred server here.

HTTP Tunnelling:
This is standards-based RTSP/RTP TCP Interleave (RFC-2326/3550) inside HTTP encapsulation to look like HTTP web server traffic to penetrate difficult firewalls. This method will usually get through content filtered firewalls where HTTP/ICY is filtered. Being standards-based, many different types of audio/video codecs may be used for these streams. Most streaming using this protocol is MPEG-4 based today. This uses an RTSP/RTP Streaming Server, such as QuickTime/Darwin Streaming Server.

HTTP Progressive Download Streaming:
This is nothing more than a file download from a Web Server, and the file plays as it is downloading, hopefully, if there is sufficient bandwidth. The file will also land in the user temporary folder, offering no security to content. This method uses a Web Server.

Hopefully, this clears up some confusion on all of this.

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Adding an MP3 playlist to your site

modcam — Mon, 11 May 2009 21:23:16 +0000

Many times, you may want to have a listener stream MP3s from your site, but you don’t have any streaming software set up. One solution is to create an M3U file which acts as a playlist that opens up with many mainstream MP3 players such as iTunes and Winamp. Following is an example of an M3U playlist:

#EXTM3U #EXTINF:199,Radiohead - Creep http://www.yoursite.com/radiohead-creep.mp3 #EXTINF:217,Pink Floyd - Money http://www.yoursite.com/pinkfloyd-money.mp3

The .m3u file can be placed on any web server, and linked to a web page with the standard a href tag. For instance, to link to a file named “playlist.m3u” from a web page in the same directory with the file, the link could be:

Play my playlist

Note: For .m3u files to work correctly, your web server must be configured to deliver the correct mime type for .m3u files. To do this with Apache (one of the most common web server applications), you can do one of the following:

In apache’s conf/ directory, open the file titled “mime.types” and add the following line: audio/x-mpegurl .m3u, and then you will now have to restart apache
In your web site’s root directory, create a file (if it doesn’t already exist) called “.htaccess”, and add the following line: audio/x-mpegurl .m3u

M3U playlists are compatible with all of GravityLab’s Audio Hosting accounts.

New Member Center Features

modcam — Wed, 18 Feb 2009 18:48:10 +0000

We are proud to announce the latest member center plug-in, our very own file viewer application. With this new feature, members are able to view all of their media files in one easy-to-use interface. This application also makes it a breeze to embed your media into any web page. Just find which video you want to link to and copy & paste the provide code. You can also customize FLV video embedding, choosing your own skinned video player that just works, no complicated uploads of javascript or flash swf players! If you don’t already have an account, sign up for our affordable video hosting today!

What are the best settings for encoding Mobile 3GP files?

modcam — Wed, 22 Oct 2008 21:32:37 +0000

Here’s a short summary of the best encoding bit-rates and formats for mobile video

Device	Total Bit Rate	Video	FPS
Nokia 3650	34 – 80 kbps	H.263, 22 – 68 kbps QCIF	5 – 8
Motorola A830, Sony Ericsson P800	34 – 80 kbps	H.263, 22 – 68 kbps QCIF	5 – 8
PocketPC	34 – 200 kbps	H.263, 22 – 188 kbps QCIF or 240×180	6 – 15

The correct way to login to our ftp server with Internet Explorer

modcam — Thu, 16 Oct 2008 19:42:14 +0000

Problem: I can’t access my GravityLab Multimedia files with Internet Explorer!

Answer: Make sure to use the following format in the URL bar for accessing your GravityLab FTP account:

ftp://username:password@ftp1.gravlab.com

The differences between HTTP downloading and true streaming

modcam — Tue, 15 Apr 2008 19:00:19 +0000

Downloading
When a user wishes to view video on your site, there are several possible methods that can allow said user to see the video. The easiest method is the create a hyperlink to the video file. This method is useful if you want the viewer to save the movie to their computer before viewing. This is fine for small files, but the bigger the file size, the longer the wait time and the less likely your viewers will want to wait for the entire movie to download before they can watch it. Delivering video files this way is known as HTTP streaming or HTTP delivery. HTTP means Hyper Text Transfer Protocol, and is the same protocol used to deliver web pages. For this reason it is easy to set up and use on almost any website, without requiring additional software or special hosting plans.

Progressive Downloading
This is a step up from hyperlinking to your video files. It is a temporary solution to the problems mentioned for downloading. The video file is embedded with code that is unique to each type of video, and as soon as enough of the video is downloaded to watch, the video will begin to play. If the user’s connection is fast enough, they can watch the video as it downloads. The disadvantage here is that the viewer cannot skip forward to any part of the video. This solution does not require any special software or streaming server to work.

True Streaming
This is the best way to deliver video to viewers if you want to allow the viewer to instantly skip to any part of the video or if you want to prevent the viewer from downloading the video file to their computer. True streaming works by delivering bits of video through a streaming server, which sends packets of data in real-time, effectively allowing the end user to view the data as it is arriving. This process is not possible with the HTTP protocol. Instead, RTSP is the protocol of choice for streaming media. It stands for real-time streaming protocol, and it is a method of routing video data to the end user. RTSP provides “VCR-style” control functionality such as pause, fast forward, reverse, and absolute positioning, which cannot be achieved with HTTP.

Which method should I use?
If you are serious about your videos, true streaming is the best option for delivering media to a global audience. With instant-access, built in download prevention, VCR style controls, and affordability, there’s never been a better time to start delivering streaming media to your audience. With GravityLab Multimedia, you can have the best of both worlds. We provide methods to access your streaming media via HTTP and RTSP, allowing you to choose which method is best for you. Check out our streaming video hosting plans
to see which plan best fits your needs.

Expression Encoder 2 for Silverlight and Windows Media

support — Thu, 20 Mar 2008 07:25:16 +0000

From the Microsoft Expression Encoder download site:

“Microsoft^® Expression^® Encoder, a feature of Expression Media, offers encoding, enhancement, and publishing of rich media experiences to Microsoft Silverlight. ”

Features Include:

Better Encoding

VC-1 advanced authoring SDK integration: by adopting the new VC-1 authoring SDK, Expression Encoder 2 is able to author better quality video faster. We’ve exposed a set of presets for tuning the encoder as well as detailed settings with comprehensive tooltips for the advanced compressionist.

New profiles, and video codecs for streaming media: Encoder 2 supports a number of new modes and codecs including Quality VBR, WMA Pro (stereo), WMA Lossless, 24 bit audio and audio/video encoding stream selection.

Improved MPEG source support: We now include an MPEG 2 decoder in the product to give a consistent story across platforms. The decoder we ship supports transport streams (so you are able to work with sources that originated from HDV cameras. Seeking performance and accuracy has been greatly improved.
Better multi-core performance: we are not done with performance enhancements by any means but have made decent progress in Expression Encoder 2, particularly on multi-core systems.
Improved aspect ratio handling: by default, the new Profile Adaptive mode is selected which preserves the width specified in the profile but varies the height according to the aspect ratio of the source. Translation: it just works. Additionally, when Source compression is used the aspect ratio mode as well as pixel aspect settings are fixed up to ensure source compression will just work.
Pre-processing enhancements: the new Pre-processing palette contains a number of settings for controlling resizing (Bicubic, Lanczos, Supersampling in addition to nearest neighbor and bilinear), de-interlacing and audio options. As well as detecting the need to de-interlace from the header of the file, the user can manually override the defaults. In addition to the V1 capabilities, Expression Encoder 2 includes inverse telecine as well as a new pixel-adaptive de-interlacer. On the audio side, there is a volume leveling filter as well as a volume control.

Better Silverlight Interactive experiences

The second bucket of functionality covers improvements to Silverlight output.

New templates: We’ve revisited both the functionality and the design of our core Silverlight Templates. As before these support core functionality such as Chapter points and close captioning and are user extensible.
Template Parameters: We have had a lot of requests for more and easier control of how templates behave. Examples include not automatically playing (or buffering) the video, being able to control the background color of the HTML and more. In Expression Encoder 2 we’ve added parameters to templates. The parameter system is extensible enabling developers to easily expose custom things e.g. skin primary color etc.

Download Expression Encoder for Microsoft Silverlight

Converting DVD to Streaming Video

modcam — Wed, 05 Dec 2007 19:52:25 +0000

Before you read ahead, consider GravityLab Multimedia’s streaming media encoding services. We take the complexity out of creating streaming media for an affordable price.

Often times, companies that wish to stream their media are given video from a production company on a DVD. This is a great multi-purpose archival format, because the disc is high capacity, and therefore can store high-quality video. Until recently, DVD video was difficult to extract and convert into video files. If you’ve ever looked inside the DVD on your computer, you would have noticed all sorts of VOB, IFO, and BUP files. This is a confusing mess of files, and it takes specialized software to convert this data into streaming video.

One way to convert the audio and video on a DVD to WMV format is to capture the content using an analog capture device. You can connect the audio and video analog outputs of a DVD player to a video capture card on your computer, and then use Windows Media Encoder to encode the video to a file. But this requires a video capture card, and is a subject for another time.

If you want to convert digitally, you have a plethora of DVD extraction utilities for both Windows and Mac users.

Windows users:
DVDx, available on SourceForge.net. This program is able to convert DVDs directly to Windows Media Format, as well as AVI, MPEG. and WM9.

Once you have created an AVI or WMV file from the DVD, you can use the free Windows Media Encoder
to prepare the file for web streaming.

To configure Windows Media Encoder 9 Series to encode a file

On the toolbar, click New Session. The New Session Wizard starts.
On the Wizard tab, click Convert a file.
On the File Selection screen, type both the file that you want to convert (the source file) and the file that you want to create (the output file).
On the Content Distribution screen, click Web server (progressive download). When you click Web server (progressive download), only those encoding options that pertain to encoding files for Web servers are displayed.
On the Encoding Options screen, select how you want to encode your audio and video from the lists, and then click to select the appropriate bit rate check box.
On the next two screens, type display information and review your settings.
After you quit the wizard, click Start Encoding.

Now the video should be ready to upload to your account!

Mac Users:
Check out this list of video software for OS X: http://www.pure-mac.com/video.html

Insert the DVD into your computer
Extract the video from the disk using Cinematize. This highly recommended program extracts DVD into Quicktime DV format which can then easily be encoded into a streaming file
Use one of the following to export your video:
- For best results, use Apple’s Compressor (bundled with Final Cut Studio). Its algorithms produce high-quality, low-filesize video in Quicktime and Windows Media format
- Quicktime Pro is a low-cost option for converting videos, but filesize is typically larger and quality isn’t as top-notch. But it does the job. From the menu bar, choose File > Export, then on the Export drop-down menu, select “Movie to Quicktime Movie”, then for the drop-down below that, (Use:) select “Streaming – Medium”.
- Quicktime Pro for .wmv files: You will need a plug-in called Flip4Mac. Then export video using Quicktime Pro’s “Movie to Windows Media” option.

Bit-rate requirements of common connection speeds

modcam — Fri, 02 Nov 2007 18:40:02 +0000

When streaming media over the web, it is important to take into consideration the speed at which your viewers are connecting to the internet. Listed below are several common connection speeds and the corresponding bit-rate at which your videos will need to be encoded in order to play back smoothly. Bit-rates are listed in Kilobits (1000 bits = 125 bytes)

Bit-rate	Connection Speed	File Size Per Minute of Video
21 Kbits/sec.	28.8 modem users	160 KB
37 Kbits/sec.	56K modem users	280 KB
80-100 Kbits/sec.	ISDN	600-750KB
150-200 Kbits/sec.	High Speed ISDN	1.13 MB
250 Kbits/sec.	DSL, cable modem, satellite dish	1.88 MB
300 Kbits/sec.	DSL, cable modem, satellite dish	2.25 MB
500 Kbits/sec.	Fast cable modem	3.75 MB

How to tell if video can be streamed

modcam — Thu, 01 Nov 2007 20:07:40 +0000

All files that are to be streamed must be hinted for streaming. This is made possible by the hint track, which is a small piece of data inside a streaming movie file. Our streaming servers recognize the hint track and use it to guide the streaming process. The hint track is never sent to the viewer, it always resides on the server.

Hinting your movies is essential for streaming media hosting, because without a hint track, the viewer will see an error instead of video.

Quicktime Pro provides the ability to check for hint tracks in a video. Simply open the video qith Quicktime Pro, and select Window > Show Movie Properties. If there is a hint track, you will see the words “Hint Track” under the Name column.

If there is no hint track, contact us and we would be glad to help you prepare your media for online delivery.

Multiple bitrate video streaming

modcam — Wed, 10 Oct 2007 18:15:13 +0000

In order to provide the best quality video possible to the widest range of viewers, it is necessary to tailor the bit rate of the video to match the download speed of the client’s connection. This is possible to do with Windows Media Server, Real Producer and Quicktime.

The most difficult task of streaming audio and video over a network is maintaining a continuous presentation to the user in a highly changeable environment. Buffering is the biggest problem of streaming digital media. It is caused when the client runs out of data in memory, called the buffer, and must wait for more to arrive. The client will always run out of data if the bit rate of the incoming stream exceeds the current available bandwidth.

Unpredictability of bandwidth is taken for granted on the Internet. For example, just because a user connects to an ISP at 56 Kbps does not mean there is 56 Kbps of bandwidth available to the user at all times. The actual bandwidth at any given point is determined by network conditions and traffic on the Internet, which is constantly fluctuating, causing bandwidth to drop to 18 Kbps one moment, and then increase to 40 Kbps the next. If a user attempts to view video being streamed at 50 Kbps, the presentation suffers considerably when bandwidth is squeezed.

Windows Media

To ensure a continuous presentation, Windows Media technologies use intelligent streaming, which adjusts the bit rate of the content stream to counteract changes in available bandwidth. When a user first connects to a stream, intelligent streaming ensures that the client receives content at the bit rate that is most appropriate for the current bandwidth. As the user continues to play a stream, intelligent streaming dynamically and seamlessly adjusts the bit rate of the streaming content as the available bandwidth changes.

Multiple-Bit-Rate Encoding

To take full advantage of intelligent streaming, content must be encoded as a multiple-bit-rate stream. In multiple-bit-rate encoding, a number of discrete, user-definable audio and video streams are encoded into a single Windows Media stream. The streams are encoded from the same content, but each is encoded at a different bit rate. When Windows Media Player connects to a Windows Media server to receive a multiple-bit-rate Windows Media file or broadcast stream, the server only sends the set of audio and video streams that is the most appropriate for current bandwidth conditions. The process of selecting the appropriate stream is completely transparent to the user.

How to create multiple bit rate files

To encode content that takes advantage of intelligent streaming, you can simply use one of the multiple-bit-rate destinations provided in Windows Media Encoder. For greater control, you can manually select the bit rates for each audio and video stream within a multiple-bit-rate stream. Client post-processing and intelligent bit rate optimization are all automatic, on-the-fly features. Best of all, you only need to create and manage a single file to handle multiple bit rates.

To understand the following topics, you should be familiar with the operation of Windows Media Encoder 9 Series. For more information about encoding, see Windows Media Encoder Help.

Setting Up the Encoder
To set up a multiple-bit-rate encoding session, do the following:

Open the Session Properties dialog box in the encoder, and click the Compression tab.
In Destination, click Windows Media server (streaming).
In Audio and Video, click the type of audio and video you want to encode.
Select more than one of the bit rate check boxes. The number of bit rate choices changes depending on the audio and video type you chose.
If you want more manual control of the encoding session, on the Compression tab, click Edit.
Optionally, in the Custom Encoding Settings dialog box (shown in the following figure), you can add and configure custom target bit rates, and then modify the settings of each bit rate by clicking the corresponding tab. Multiple-bit-rate encoding is only available if you select the constant-bit-rate (CBR) encoding mode.

If you want to use intelligent streaming with multiple-bit-rate streams, the content must be hosted on a Windows Media server and played in Windows Media Player. You can create files that contain multiple-bit-rate streams and play them locally or from a Web server, but only the highest bit rate streams will play.

For more information about editing or creating profiles that encode with multiple bit rates, see Windows Media Encoder Help.

Viewing the Process
After you have configured an encoding session for capturing multiple-bit-rate content and have connected and adjusted the video and audio streams, start encoding. If your computer meets the requirements for encoding high-bit-rate content, you can capture and encode multiple-bit-rate content. The more streams you encode, however, the faster the CPU and more memory your computer requires.

Quicktime

You face a tough choice when you want to deliver your QuickTime movies over the web. Part of your audience has a dialup connection and a slow computer and can’t view large movies with high frame rates. They need small, highly compressed movies. The other part of your audience has a fast connection and a fast computer and easily watch higher bit rate videos. They want movies with the highest possible video and audio quality. How do you satisfy both?

With QuickTime, you don’t have to choose–you just use a reference movie. A reference movie contains pointers to alternate data rate movies–that is, multiple versions of the movie designed for downloading at various data rates.

For example, you could create three versions of a movie–a version optimized for 56K dialups, a version for DSL or cable modems, and a version for T1’s and higher–put them all on your webpage, and have the reference movie choose which is appropriate for each viewer.

That’s right, QuickTime 3 and later can auto-select the right movie for any connection speed (or CPU speed, or language, or QuickTime version) in the QuickTime Settings dialog without the viewer having to make a choice, and without special coding on your part. You can even create a default movie that plays if none of the criteria are met.

To create a reference movie/alternate data rate movie setup, you’ll need the Pro version of QuickTime Player and an application that allows you to make a reference movie, such as Peter Hoddie’s XMLtoRefMovie utility, or Apple’s free MakeRefMovie utility.

Making alternate data rate movies

Creating the alternate data rate movies is a straightforward process.

Start by creating a master movie of the highest possible quality. That means the largest frame size, the highest frame rate, and the least compression on audio and video tracks. You’ll be making the alternate movies from this master.
Determine the number of alternate data rate movies you want to create, and the rate for each one. A typical spread for web delivery is one each for 56K (56 Kbits/sec max, but usually much lower), DSL/cable (up to about 128 Kbits/sec), and T1/T3 (up to 1 Mbit/sec). If you are delivering media on CD-ROM, you may want to create a spread for slow computers and fast computers, or for 2X, 8X, and 24X drives.
Create the alternate data rate movies from the master using the appropriate image dimensions and codecs. You can do this in QuickTime Player using the Export option in the File menu.
If some of your alternates are streaming movies, make Fast Start movies that point to them, and use the Fast Start movie as the alternate for the stream. To create a Fast Start movie that points to a streaming movie, open the streaming movie in QuickTime Player by choosing Open URL from the File menu and typing in the URL. Then choose Save As from the File menu, name it, and save it as a self-contained movie.
Also create a default movie that anyone in your audience can see, no matter what connection or computer they are using. It could be a few frames from your movie with a low-bandwidth audio track, or a single image with a scrolling text track and no audio, or just an image. In any case. keep it very small, because the browser will download it even if an alternate movie is used.
Name each movie in a logical way, including the .mov filename suffix. For example, you may want to name your alternate movies altmov01.mov, altmov02.mov, and altmov03.mov. Save as self-contained movies. Store them all in the same folder or directory.

Making a reference movie

You can make a reference movie for alternate data rates based on connection speed or other criteria using an application such as the free utility program MakeRefMovie, available from Apple for Mac OS 9 , Mac OS X, and Windows. The latest version of MakeRefMovie can also create reference movies that choose among alternate movies based on CPU speed, language, or QuickTime version.

Once you’ve made the alternate movies, follow these steps in MakeRefMovie:

Open MakeRefMovie.
Save your new document in the same folder or directory where the alternates are located. Make sure the reference movie filename contains the ‘.mov’ extension. This reference movie will call upon the alternates.
Drag each of the alternate movies onto the window of MakeRefMovie. An alternate movie will appear for each file you drag-and-drop. Or you can open each file separately by choosing ‘Add movie file’ from the Movie menu or you can type the URL to your streaming movie by selecting “Add URL” from the Movie menu.
Set the minimum connection speed for each alternate movie in the Speed: pop-up menu.
Set the load order of the movies in the Priority: pop-up. For example, you may want the reference movie to call the highest quality movie first, then the medium quality movie, and last the lowest-quality or default movie. If there is more than one movie designed for the same connection speed, set a priority for which movie will load first.
Specify the default movie by checking Flatten into output. The default movie should be compressed with a codec supported by older versions of QuickTime for backward compatibility. This checkbox can only be applied to one movie.
Save the reference movie and place it and all the alternate movies in the same directory. Upload the directory or folder to the server.
If you are putting the movies on a webpage, embed the reference movie into the HTML using the tag. The reference movie will load the appropriate alternate based on the viewer’s connection speed. More about embedding QuickTime movies into webpages using HTML.

Can videos stream over the http:// protocol?

support — Tue, 08 May 2007 04:17:37 +0000

http: defines a port that normal web servers use to deliver content. Port 80, to be precise. Sometimes that content is .html, sometimes it is .jpg image files, sometimes it is mp3’s or video files. You want to know that your video is being served from a streaming server. At GravityLab, it is.

Your multimedia, when pushed through mms://, rstp:// or http://via the 554 port protocol, is being pushed through Windows Media Services 9, Helix Universal, or Quicktime Streaming Server respectively. What http:// can, considering video MIME types with apache, is port 80. So if you link to video through http: but you specify the 554 port (ie:http://helix.gravlab.com:554/youraccount/yourfile.mov) http: loses all meaning in terms of defining a standard Port, because it is using the Quicktime Streaming Server 554 port.

Hinting a Quicktime movie for real-time streaming

support — Tue, 08 May 2007 04:00:19 +0000

To set up a movie for streaming over the Internet, compress the movie so that its data rate is appropriate for the bandwidth at which your users will connect. You can use the hinted streaming format with QuickTime Streaming Server or Darwin Streaming Server. The hint tracks, which are stored in the movie along with the video, audio, and other tracks, provide QuickTime Streaming Server software with information about the server, the transmission packet size, and the protocol to be used–in short, how to send the movie data over the network.

When you choose hinted streaming, “hint tracks” (information needed to stream the movie) are added to the movie. If the movie is already in the desired format, you can prepare a movie for streaming by opening the movie in QuickTime Player and choosing Export from the File menu, then Movie to Hinted Movie. If you want to change the movie’s format, follow the steps below.

Converting a movie for real-time streaming

Open your movie in QuickTime Player.
From the File menu, choose Export.
From the Export pop-up menu, choose Movie to QuickTime Movie.
Choose a streaming option from the Use pop-up menu.
Click Options and select the “Prepare for Internet Streaming” checkbox.
Choose Hinted Streaming from the pop-up menu and click OK.
Click Save.
Upload your video to your account
Link to your video through QTSS via the 554 port using the instructions sent to your account

If you want to stream a QuickTime movie using QuickTime Streaming Server, you should use a web-optimized video or audio compressor to compress the movie file. All QuickTime compressors are compatible with QuickTime Streaming Server, but the compressors listed below are optimized to give the best results for delivery over the Internet.

For a complete list of QuickTime-supported compressors, see the Products area on the QuickTime website.

Video compressors
H.264, MPEG-4, Sorenson Video (any version), H.263, H.261

Audio compressors
AAC, QUALCOMM PureVoice, AMR, QDesign

Can I upload AVI into my account?

support — Fri, 27 Apr 2007 22:07:34 +0000

You’ll probably want to convert your AVI file to Windows Media. It’s a much better streaming video than AVI when delivered over the web. Windows Media Encoder is a free utility from Microsoft that you can download here – http://www.microsoft.com/windows/windowsmedia/9series/encoder/default.aspx
However, I don’t see any AVI file in your account. I don’t think you could have uploaded it last night while the account was locked. Remember, since you’re uploading video to our delivery network, it can take quite awhile for your file to finish uploading (it starts uploading when you drag it to the folder, but can take awhile). If you do use your AVI file on myspace, the link would look like this:

mms://media.gravlab.com/your-account-name/filename.avi

http://media.gravlab.com/your-account-name/filename.avi

Streaming, Broadcasting, and Progressive Download

support — Fri, 27 Apr 2007 21:52:36 +0000

Digital video files are usually stored to disk in movie files. These files often contain the sample data used by the movie as well. The Player API includes functions to store a movie, or a movie and all its associated sample data, to a file. By default, the movie data structure is stored at the beginning of the file, followed by any sample data, such as in Quicktime. By default, the sample data is interleaved, so that media samples that are displayed at the same time are stored close together, with the samples needed earliest stored first.

This typical streaming encoded movie file can be delivered by any web server, using common protocols such as HTTP and FTP, just as if it were an HTML file or a JPEG image. It is necessary only to name the file correctly and associate the filename extension with the correct MIME type on the server. (The correct filename extension for QuickTime movies is .mov, and the correct MIME type is 'video/quicktime'.)

When a file is delivered over a network or downloaded over the Internet, the entire file is not available immediately, but a typical QuickTime movie can be played while it downloads. This is called progressive download, or Fast Start. It works because the movie atom is stored at the beginning of the file, so QuickTime knows how to interpret the movie sample data even before it arrives, and because the movie data is intelligently interleaved with respect to display time.

It is also possible to create a movie file with the sample data stored first, followed by the movie data structure. This is not usually desirable, because the entire file must download before QuickTime can interpret the sample data. You can correct this kind of data inversion simply by opening the movie file in QuickTime and saving it as a new, self-contained file. QuickTime stores the movie data structure at the beginning of the file by default.

A QuickTime movie file may contain only a movie data structure, pointing to sample data in other files or URLs. In most cases, this type of movie can also play as the movie data downloads, because, again, the movie data structure allows QuickTime to interpret the incoming data, and because the data source for each track is specified independently, causing the network to perform a kind of interleaving by delivering all of the media independently and simultaneously. Obviously, this kind of interleaving is less reliable than the deliberate interleaving QuickTime does when creating a self-contained movie file, so playback may not always be as smooth.

When the bandwidth of a connection meets or exceeds the data rate of the movie, a well-formed QuickTime movie file can play as it downloads. This kind of progressive download, or Fast Start movie, provides the same user experience as real-time streaming.

If the connection is not fast enough to play the movie in real time, you can either wait until the download completes or play as much of the movie as has downloaded at a given time. QuickTime can even estimate the required download time and begin playback when it calculates that enough data has arrived to play the movie smoothly (because the remaining data is expected to arrive by the time it is needed).

QuickTime movies can also be delivered using real-time protocols such as RTP and RTSP. This requires a streaming server, such as the QuickTime Streaming Server or Darwin Streaming Server. To stream movies in real time, the server requires information about how to packetize each track in the movie. This information is stored in special tracks in a QuickTime movie, known as hint tracks. There are functions in the API for adding hint tracks to existing movies, as well as flags that can be used to tell QuickTime to create hint tracks when saving a movie to disk.

Movies with hint tracks can also be delivered using HTTP or FTP protocols for progressive download, but additional bandwidth is needed to carry the hint tracks, which are used only for streaming. Consequently, it is best to determine how you will deliver a movie before saving it as hinted or nonhinted.

In addition to progressive download and real-time streaming of stored movie files, QuickTime supports broadcasting, the creation of one or more real-time streams from real-time sources, such as cameras or microphones. This involves capturing the incoming data, compressing it to the desired bandwidth, and generating streams of outgoing packets, all in real time. The QuickTime broadcast API is currently available for the Mac OS only; it is not available for Windows or Java.

What is GravityLab’s streaming media hosting?

support — Fri, 27 Apr 2007 21:51:52 +0000

The GravityLab Multimedia content delivery network is comprised of best-of-breed streaming media servers located directly on the fiber optic North American internet backbone. What that means, basically, is that your media content is delivered on demand very quickly to a global audience using the best Internet path directly into their homes.

You are able to deliver all the major streaming media formats from one account. You simply FTP your video to your account, and then link to your video or audio assets from your web site. We try to make it as easy as possible for you to deliver streaming media to your audience.

Once you open your account, within 24 hours you can begin uploading your video. If you need your video encoded to streaming media formats, we can do that as well from your source media.

How to calculate your bandwidth use for streaming media hosting

support — Mon, 05 Mar 2007 21:33:55 +0000

How to Start?
Most people who are evaluating the use of the GravityLab’s Media hosting for audio and video will reach a point where they have questions along the lines of the following:
“Which streaming media hosting plan should I choose?”, “should I use Windows Media, Quicktime, Flash or some combination?”, “how much storage allocation will I need?”
Calculating Simultaneous Users:

Most companies do not have accurate estimate of the number of simultaneous users on a particular portion of their web site. In general, web stat logging software typically does not provide this much granularity. In fact, if your client tells you that they expect a hundred thousand, a half of million, or even a million or more simultaneous users, it is probably time to raise a red flag.

Unless you are building the next version of Yahoo’s IM, MSN’s IM, or AOL’s IM, your web site will not see this amount of simultaneous traffic. Chances are your client was talking about the amount of total page views or hits over the course of some time frame.

For this reason, it is important to understand what we are looking for. The number of simultaneous users that will be using your application at peak load is the maximum amount of users that will be using your application at the same time. It is not the total number of users who will ever use your application. It is not the number of people who have used your application in a single day. The number of simultaneous users that will be using your application at peak load will likely be much lower than the total number of users of your application.

How to Estimate Number of Simultaneous Users:

Since this the number of simultaneous users is such an important piece of information for determining which hosting plan you choose for your account and the bandwidth capacity you will need for your application, we will walk you through one way of estimating this number when the only information you have is very general web page statistics.

We’ll use a hypothetical case: The ACME Company intends to launch a 10 minute marketing video linked off the home page of their web site for 20 days to promote an upcoming product launch. They have stats from their last product launch that showed 150,000 people viewed the promotional materials during that 20 day campaign. In this example, we also know that almost 50% of this traffic occurred in the first 5 days of the campaign.

To find an estimate for the number of peak simultaneous users, we’ll try to find the single hour in which the most users viewed the video and then make an assumption that 1/6 of the visitors in that hour will be watching the video simultaneously. The 1/6 factor is a simplifying assumption based on the fact that the viewers will be distributed evenly in that peak hour and each will be viewing the video for only 10 minutes of a possible 60 minutes in the hour. Therefore at any one point in the hour, on average, only 1/6 of all of the viewers in that hour would have been viewing the video simultaneously (given a random distribution).

In the example above, since we don’t know how many visitors our site will have during the peak hour, we’ll need to make some more assumptions. First, since we know that about 50% of the traffic will occur during the first five days, let’s assume that there is a spike in traffic during the first five days, and then traffic gradually decreases. With these assumptions, and the fact that we expect 150,000 viewers over 20 days with about 50% of those in the first five days, we can use Microsoft Excel to model up an estimate of daily web traffic.

In this example, our model would suggest that the day with the largest amount of viewers would be Day 4 with 16,250 viewers. The next step is to find the hour with the greatest amount of expected viewers. Making the assumption that this marketing campaign will be aimed predominately at US audiences, we can use Excel to develop a similar model of estimated traffic per hour during the day.

The distribution of traffic into the various hours as shown above roughly models the traffic we’ve seen for certain videos deployed on macromedia.com. Using this model with our ACME Company example we’ve now identified that the single hour during the entire campaign (20 days) with the most viewers will be from 11AM – 12noon PST on Day 4 and that there will be 1,950 viewers at this time.

We can now multiply the 1,950 viewers during the peak hour by 1/6 to get the estimate for the peak number of simultaneous users. In this case, our estimated number of peak simultaneous viewers of this video will be 325.

Examples of Calculating Simultaneous Users

In this example, the application is a oneway datacasting system that streams real time monitoring info to a group of end users. In this example, the Media Server will serve only one stream to each user.

Simple Connections Formula

A simple way to calculate simultaneous users can be made with the
following data points:

Total Users over a known time period

Average Connection Time for a user (normalized)

Formula:

U(s) = U(T) / (T / A)

U(s) = Simultaneous users
U(T) = Total users
T = Time period
A = Avg. connection time

Windows Media encoding for Windows Media Services hosting

support — Thu, 01 Mar 2007 22:29:45 +0000

Preparing Your Content

Windows Media Player renders audio and video content in the same way, whether a file is on a Windows Media server, a Web server, a network server, or a local hard disk. The server does not affect the quality of the media. What the server does affect is how the packets of data that contain the media are delivered to Windows Media Player.

A Windows Media server is designed to handle busy, congested networks and low-bandwidth connections to client computers that are running Windows Media Player. This section describes what you should consider before you encode content that will be hosted on a Web server, and then shows you how to configure Windows Media Encoder 9 Series.

Encoding Content for a Web Server
If you stream by using a Web server instead of a Windows Media server, keep these things in mind:

A Web server is not designed for streaming media, so playback is more likely to be interrupted by periods of buffering. Buffering occurs when Windows Media Player is not receiving audio and video data packets fast enough. Windows Media Player has to stop to refill its memory buffer before it can proceed with playback. To help correct for this, you may have to encode files at a lower bit rate than you would if they were being streamed from a Windows Media server.
Web servers do not support intelligent streaming. Multiple-bit-rate files contain a number of video streams—each of which are encoded at a different bit rate. These files enable the server to perform intelligent streaming. When using intelligent streaming, Windows Media Player sends feedback to the Windows Media server about current network conditions. The Windows Media server then delivers the most appropriate video stream for the current bandwidth from among the streams that are contained in the file. Because a Web server has no mechanism for dealing with intelligent streaming, it sends the entire file, which contains all the streams, and only the highest bit rate stream plays. This can result in wasted bandwidth and a poor user experience.

Procedures
The procedures in this section describe how to configure Windows Media Encoder 9 Series for Web server streaming. You can download the encoder from the Windows Media Web site. These procedures include:

How to configure Windows Media Encoder 9 Series to encode a file.
How to create a Windows Media metafile.
How to add a tag to an HTML file.

To configure Windows Media Encoder 9 Series to encode a file

On the toolbar, click New Session. The New Session Wizard starts.
On the Wizard tab, click Convert a file.
On the File Selection screen, type both the file that you want to convert (the source file) and the file that you want to create (the output file).
On the Content Distribution screen, click Web server (progressive download). When you click Web server (progressive download), only those encoding options that pertain to encoding files for Web servers are displayed.
On the Encoding Options screen, select how you want to encode your audio and video from the lists, and then click to select the appropriate bit rate check box.
On the next two screens, type display information and review your settings.
After you quit the wizard, click Start Encoding.

If you want to edit or create a new a profile, click Properties, and then click Edit on the Compression tab. In the Custom Encoding Settings dialog box, you enter the primary settings that the encoder will use to create your content. Keep in mind that the file you encode for a Web server must be able to play as it is downloading (progressive download). Therefore, for the smoothest playback, you should choose CBR (Constant Bit Rate) mode and only one bit rate.

Note: Creating and managing profiles is a method provided for advanced users with a detailed knowledge of bandwidth capacity, media settings, and codec usage. For more information, see Windows Media Encoder Help.

After you encode your files, there are two more steps to prepare your content for streaming from a Web server: creating Windows Media metafiles with .wax, .wvx, or .asx file name extensions, and adding tags to your HTML files. The HTML tag points the user’s browser to the metafile, which points Windows Media Player to the content (the Windows Media file). You must use a metafile to reference the media because a direct reference to the media in an HTML tag will cause many browsers to attempt to download the media rather than stream it.

To create a Windows Media metafile

Open a text editor, such as Notepad.
Type the following metafile script, but replace the URL with that of your file. Reference the audio or video file just as you would any other Web file.
You can place the metafile in the same folder as that of your digital media file. If you do so, you can use a relative path, which is simply the name of the file. The REF line would look like this:
Save the text file using the name of your digital media file followed by the .wvx extension if the metafile points to a file with a .wmv extension, or .wax if the metafile points to a file with a .wma extension, such as YourFile.wvx. You can also use the .asx file name extension for either audio or video.

When an end user clicks the reference on the Web page, the metafile is downloaded and Windows Media Player opens. Windows Media Player opens the metafile, and then opens and plays the Windows Media file from your Web server.

Streaming Media and Progressive Download explained

support — Sat, 06 Jan 2007 07:06:42 +0000

How do you choose whether to deliver a movie using progressive download, streaming, or broadcasting? It’s an important question for you, and since GravityLab’s business is delivering your content to your audience with the best possible user experience in mind, it’s an important question for us, too.
All all of the major streaming media codecs, both audio and video, can be delivered as progressive downloads. Streaming is limited to sound, video, and text. Broadcasting is further limited to compression schemes and quality settings compatible with real-time capture and compression.

Progressive download works even when the bandwidth is not sufficient for real-time playback; it simply buffers incoming data and delivers delayed playback. However, since it is simply a web server delivering your content through the HTTP protocol, many simultaneous demands for that media can result in a poor audience experience with significant buffering while the player waits for the content from the server. The back end infrastructure of the GravityLab content delivery network provides client / server negotiation for delivering the content in a timely, efficient manner for the best possible audience experience. This is important, since your online user’s patience, speaking in statistical averages, is about 4 seconds before they move on.
Streaming movies do not store a copy of the movie on the client computer, making them inherently more difficult to copy without the consent of the movie’s owner. This can be an important consideration, and is one reason why people choose streaming over progressive download.

Streams take up a specified amount of bandwidth, whereas HTTP file downloads proceed as quickly as the connection allows. It is therefore easier to manage the bandwidth usage of a streaming server than of a web server delivering progressive-download movies. With the proliferation of high speed internet connections at home, and because the vast majority of the US workforce has high speed access at work, delivering video content at predefined multiple bit rates (streaming) makes sense.
Broadcasting allows you to deliver coverage of live events as they happen, or to provide real time “chat” between computers. GravityLab provides live video broadcasts that can scale up as your audience grows.
To sum up, if your movie includes live coverage, you must use broadcasting. If bandwidth management and copy discouragement are paramount considerations, streaming may be your best choice for stored content. If bandwidth is not a concern, you want users to be able to receive you media regardless of connection speed, and you don’t mind if users obtain the actual copies of your audio and video content on their computers and portable devices, progressive download may be viable.

Using a Windows Media Server vs. a Web Server :

A Windows Media server is often the best way to stream media because Windows Media Services is designed specifically for that purpose, and all Windows Media components work together to enhance the end-user experience. Intelligent streaming, for example, involves Windows Media Encoder, Windows Media Services, and Windows Media Player.

This section compares the features of a Windows Media server and a Web server and describes the best way to determine which option is right for you.

Comparing server features
The features of each type of server are compared in the following table.

Feature

Windows Media Services

Web server

Table 2. Comparison of features for streaming Windows Media-based content

The following list describes each feature. If you are interested only in the features that a Web server can provide, then Web server streaming may be the right option for you.

Stream through most firewalls. Firewalls are special servers that filter information that flows between the Internet and private networks or intranets. Many firewalls are set up by default to block data that isn’t from a Web server—data such as a Windows Media stream. Firewalls can be reconfigured to allow this data into the intranet. Alternatively, Windows Media servers can be configured to stream using the same protocol as Web servers, HTTP.
Stream content with Digital Rights Management. Content that has been packaged using Microsoft Windows Media Rights Manager can be streamed or downloaded from either type of server. Windows Media Rights Manager helps content owners distribute licensed digital media over the Internet with superior audio quality.
Fast Streaming. A feature of Windows Media Services that allows for a combination of streaming, downloading, and caching to provide the best user experience. Fast Streaming includes Fast Start, which downloads the first few seconds of the content at as high a bit rate as possible, so the wait to start playing is reduced; Fast Cache, which uses available bandwidth to cache as much content as possible ahead of playback; Fast Recovery, which sends error correction data with the data packets instead of waiting for an error to occur; and Fast Reconnect, which enables the server to automatically restore connections that are lost.
Stream without downloading. Content from a Web server is downloaded. If Fast Cache is enabled on a Windows Media server, content might be cached to enhance playback. However, this feature can be disabled if you want your content streamed only.
Broadcast (live). Web servers can only host on-demand content (files). A Windows Media server can host content for on-demand delivery or as a broadcast. Broadcasting enables you to stream live content (events that occur in real time), and files and playlists that are played back from the server. Some examples of broadcasting are streaming live radio and television signals, and Internet radio stations.
Intelligent streaming. As mentioned earlier, this feature requires an interaction between a Windows Media server and Windows Media Player to optimize the stream for the current available bandwidth.
Optimized for streaming Windows Media content. Windows Media Services was designed for the special requirements of streaming media. For example, Windows Media Services handles resources on a computer better than a Web server when streaming. A Windows Media server is capable of delivering more concurrent streams on a given computer by making more efficient use of a computer’s CPU and network bandwidth. A Windows Media server sends data at the same bit rate as the content. A Web server on the other hand does not control the bit rate at which it sends a stream. Consequently, two or more concurrent streams from a Web server could saturate a network’s bandwidth.
Files are streamed from a Web server by using a method called progressive downloading. This means that a file plays as it downloads to the user’s Internet cache. This can be a concern for users, because digital media files often consume a large amount of hard disk space. Also, a user cannot seek to different parts of the content, until the entire file is downloaded.
Indexing. This feature provides end users with a means of fast-forwarding and rewinding through a file that is being streamed, which requires interaction between a Windows Media server and Windows Media Player.
Administering and logging. You can control how a Windows Media server manages live content and files, and monitor overall system activity in real time. You can also create detailed logs that include data such as individual client connection information and server events.

Quicktime tools for streaming video

support — Sat, 06 Jan 2007 06:34:44 +0000

If you want to stream Quicktime files, you will need to encode the videos correctly so they can be played on a streaming server. GravityLab provides this encoding service for affordable prices. We make the process simple for you so that you don’t have to acquire a new skillset just to get your videos online. However, if you are technically inclined, check out the following utilities for Quicktime files.

Streaming Tools
QTPlayer Streaming Info Plug-in	Mac OS	Win32
This plug-in adds an Info Panel for streaming tracks that shows packet transfer information.
QTStreamSplicer	Mac OS	Win32
This tool allows you to add an image to an audio only live stream. (or in front of a streaming track)
Hint Track Profiler	Mac OS	x
A diagnostic tool that graphs a streaming movies hinted packets over time.

Webmaster Tools
Plug-In Helper	Mac OS	Win32
Associates URLs as well as stores QuickTime Plug-In settings inside a QuickTime movie.
MakeRefMovie	Mac OS	Win32
Creates alternate movies for various internet connection speeds, CPU’s, languages, and more. This version allows you to create a reference movie that supports QuickTime 6.
MakeRefMovie X	Mac OS X	x
Creates alternate movies for various internet connection speeds, CPU’s, languages, and more. This version runs on Mac OS X and allows you to create a reference movie that supports QuickTime 7.