[asterisk-users] video voicemail

[Tilghman Lesher]

On Monday 15 February 2010 14:09:38 Olle E. Johansson wrote:
> 15 feb 2010 kl. 20.31 skrev Jeff LaCoursiere:
> > Playing around with the Grandstream GXV3140.
> >
> > I'm interested in having the video voicemail clips emailed in a format
> > that might be opened by Windows Media Player or even Quicktime.  Have
> > been googling around a lot and have tried various bits of OSS to read the
> > resulting .h264 file that asterisk is saving, but having absolutely no
> > luck.  A video nut I know took a look at the file and said it had no
> > header, and was actually convinced there was no video in it.
> >
> > Anyone else trying to do this?
>
> Asterisk is not saving a proper h.264 file, it's saving the raw RTP media.
> I think that ffmpeg had a module that could handle this at some point in
> time.
>
> Because of patents for H.264, we can't convert the media to anything
> useful.

IIRC, the actual format of the file is:
1-bit: full-frame marker
15-bits, unsigned: length of the RTP packet, in bytes
RTP-data
1-bit: full-frame marker
15-bits, unsigned: length of the RTP packet, in bytes
RTP-data
(etc.)

The format was designed to be easily convertable back into an RTP stream,
because as the format does not include audio data, it was believed that it
would never be useful outside of Asterisk's own usage.

-- 
Tilghman Lesher
Digium, Inc. | Senior Software Developer
twitter: Corydon76 | IRC: Corydon76-dig (Freenode)
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