Stas Oskin wrote:
[...]
>> Moreover, are you sure that a real-player powered device can play
>> MPEG4 or H.264 streams? Don't they only support H.263?
>
> Latest handsets (like the N series from Nokia) can play H.264, I
> suspect it has to do with Symbian update. MPEG4 is supported in almost
> every 3g device.
Are you sure they use real player for playing H.264, MPEG4, etc?
If yes, nokia probably installed some proprietary "component" that
helps real player. The standard real player (the linux version, at
least) does not seem to be able to play such streams (see my previous
emails).
[...]
>> If you have some stream that real player likes, can you post the
>> corresponding SDP?
>
> Here is a good example for live h.264 powered by DSS which:
>
> 1) Works on QuickTime *and* on RealPlayer.
> 2) Works on my mobile (N95).
> 3) Seems to be powered by VLC encoder (coupled with DSS of course).
>
> rtsp://streamer.neoarena.fi/mobile3g.sdp
RealPlayer does not like it :(
At least, the linux version of RealPlayer.
> There are several differences between SDP prepared by ffmpeg, and by
> the one the link uses:
[...]
The two SDPs are very different, because they describe two completely
different RTP sessions. Your one is using MPEG4 (and no audio), the
other SDP is using H.264 and MP4A-LATM audio (whatever it is).
The most interesting difference is that you are using in-band global
headers, and the other stream is using out-of-band. Then, there
are some additional tags such as
> a=framesize:96 320-180
and similar... Try adding them by hand to see what happens.
[...]
> 1) Indeed some required fields are missing from the SDP as you said -
> question is which are exactly?
I do not know. They are non-standard fields (not mandated by any RFC),
so it is difficult to say... If you can find some 3G standard referring
to them, this might help.
> 2) VLC encodes/transmits the mpeg4/h.264 video in way more compatible
> with RealPlayer and other players out there (while it uses ffmpeg for
> encoding, live555 is used for RTP streaming).
Judging from the SDP you posted, it is just sending H.264 with out-of-band
headers. libavformat should be able to do the same. Maybe the difference
is that vlc is adding that MP4A-LATM audio?
Luca
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