[FFmpeg-devel] x264 encoding over RTP and playing in VLC

Luca Abeni lucabe72
Fri Jun 11 12:28:06 CEST 2010

On 06/11/2010 11:53 AM, Luca Barbato wrote:
> On 6/11/10 11:44 AM, Luca Abeni wrote:
>> No, in-band extradata works ok too (SPS and PPS are just included in the
>> stream, and the player can succesfully play it). AFAIR, DVB-H even
>> recommended such a solution (ISMA and other standards mandated
>> out-of-band
>> global headers, but AFAIK no RFC requires that).
> I was pretty sure that out of band extradata were mandated for rtp and
> you use inband as a fallback.

Well, RFC 3984 says "sprop-parameter-sets: This parameter MAY be used
to convey any sequence and picture parameter set NAL units..." and AFAIK
it does not say that sprop-parameter-sets is mandatory.
(on the other hand, I think the ISMA standard says that
sprop-parameter-sets is needed. So, I think a generic RTP stream can
contain in-band or out-of-band global headers, depending on the users'
configuration, but an ISMA 2.0 stream must use out-of-band global

>> Anyway, just try the command line above (adding "-re"), and you will see
>> that it works.
> why this behaviour btw?

Which behaviour? Requiring "-re" or non using out-of-band global headers?
"-re" is just needed to tell ffmpeg to send the stream at the playback
speed; global headers are not used by default... But I do not know why :)
Adding "-vglobal 1" (or something like that) to the command line changes
this behaviour.


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