[asterisk-users] video voicemail

[Tilghman Lesher]

On Monday 15 February 2010 15:46:58 Jeff LaCoursiere wrote:
> On Mon, 15 Feb 2010, Tilghman Lesher wrote:
> > 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.
>
> Am I naive in assuming that I could extract the RTP data given the format
> above into something that is inherently h.264 encoded?

I don't see why not.  If you could do it on the far end of the original call,
then you should be able to translate it fine.

-- 
Tilghman Lesher
Digium, Inc. | Senior Software Developer
twitter: Corydon76 | IRC: Corydon76-dig (Freenode)
Check us out at: www.digium.com & www.asterisk.org