[FFmpeg-devel] Realmedia patch

Luca Abeni lucabe72
Thu Aug 21 08:56:02 CEST 2008


I am not the RTSP demuxer maintainer (and I do not feel very
comfortable with its current implementation), but I am trying
to have a look at these patches, to help merging them.
(BTW, I partly missed the previous threads about realmedia...
Can you please forward me the relevant emails, or send me
links to the ml archives, and point me to a "more split"

Ronald S. Bultje wrote:
>>> +        for (i = 0; i < n_streams; i++) {
>>> +            if (i == 0)
>>> +                stream = orig_stream;
>>> +            else {
>>> +                stream = av_new_stream (s, 0);
>>> +                stream->codec->codec_type = orig_stream->codec->codec_type;
>> missing stream != NULL check
>> besides, this stream creation in parse_sdp_a_line() is something that
>> should be commented by one of the lucas. I do not feel confident enough
>> that this is the correct approuch ...

I also had some doubts about this when looking at the patch (and the need
for changing the parse_sdp_a_line() prototype looks suspect too...).
Can you post an example SDP for which this code is needed? And a link to
some documentation about it?
Also, is this code needed for processing a session-level "a=" line, or
is it a media-level SDP line?
In the second case, I think this is the wrong approach.

> So this is indeed kind of, uhm, well, hackish maybe :]. The idea is
> that the SDP tells us which bitrates (stream rules) are possible for
> this single RTSP stream. Per stream, you can then subscribe to these
> stream-rules which you can read. I'm currently selecting one (I don't
> think many is practically possible anyway). The number of rules is
> available only in the SDP, so I need to create the additional
> AVStreams per extra stream-rules somewhere during/after the SDP
> reading.
Uhmm... Wouldn't it be possible to have only one AVStream per "m="
line, and to add something like an "available_bitrates" array (or
similar) to RTSPStream?
(I believe that in theory a new AVStream should be created only when
processing an "m=" line)
If I understand well there are not multiple different streams (one
per bitrate), but there is a single stream for which you can select
the bitrate... Or did I misunderstand something?


P.S.: here, I am just trying to help... If my email makes things
more complex instead of helping, just let me know and I'll avoid
this thread.

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