[Asterisk-video] different video formats in Asterisk

[Sergio Garcia]

A mp4 file can contain ANY streaming content, i.e audio/video in any codec.
The only thing that it's needed is a valid hint track where it's specified 
rtp data needed for streaming.

So, any streaming server (DSS for example) or app_mp4 can read an mp4 file 
and create the rtp packets with the correct timing information without 
knowing the format/codec of the media data. The only thing that's needed is 
something to create the mp4. For example rtpdump can create a mp4 from any
ethereal capture with rtp traffic.

Both app_mp4 and app_rtsp just need to what codec is to map the identifier to
the asterisk AST_FORMAT_XXX, and nothing more.
Also, app_mp4 could save any custom incomming data (in theory) and save it as
a speciall hint track to be streamed later, but this way the media track won't
be playable in a standar player, only streamed.
  
Once app_mp4 or app_rtsp receive an rtp packet they just convert it to an
ast_frame, so asterisk can do whatever they need with it (transcode for example).

Best regards
Sergio



---------- Original Message ----------------------------------
From: Klaus Darilion <klaus.mailinglists at pernau.at>
Reply-To: Development discussion of video media support in Asterisk<asterisk-video at lists.digium.com>
Date:  Fri, 20 Jul 2007 01:11:30 +0200

>Hi!
>
>AFAIK (please correct me when I am wrong) there are 3 different ways to 
>get video into Asterisk:
>
>1. native Asterisk video support. Some applications like voicemail, 
>Playback and Background support recording/sending of video. The video 
>must be h263 or h264 in a proprietary Asterisk format. This could be 
>generated with ffasterisk or gstreamer (both methods are quite 
>complicated). Audio can be provided as .gsm or .wav. The video will not 
>be transcoded, thus the client has to support h263 or h264
>
>2. app_mp4: The video must be in a .mp4 or .3gp container with hinted 
>audio+video tracks. Which Audio codecs are supported? Which Video Codecs 
>are support? Will app_mp4 make use of Asterisk's audio transcoding 
>capabilties? Video transcoding can be done explicitly with app_transcode.
>
>3. app_rtsp: Asterisk will receive the video from a streaming server 
>(usually DSS). Which formats are supported? Can DSS process any video 
>formats or do we need to transform the video into .mp4 before giving it 
>to DSS?
>
>IMHO a big problem is that there is no single common way to generate 
>video files for Asterisk and all the methods to generate video are very 
>complicated (except you can afford to by helix mobile producer).
>
>comments, corrections and answers are very welcome
>thanks, klaus
>
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