[FFmpeg-devel] WunderRadio changes

[Ronald S. Bultje]

Hi,

On Mon, Aug 23, 2010 at 11:23 AM, Martin Storsj? <martin at martin.st> wrote:
> On Mon, 23 Aug 2010, Ronald S. Bultje wrote:
>
>> On Mon, Aug 23, 2010 at 9:50 AM, Martin Storsj? <martin at martin.st> wrote:
>> > On Mon, 23 Aug 2010, Diego Biurrun wrote:
>> >
>> >> I just had a 5 minute look, so I don't know any details, but there
>> >> are some changes in there that we might wish to pick up: RTSP stuff
>> >> and some ARM libswscale improvements.
>> >
>> > A quick check of their RTSP changes:
>> > - Hardcoded to use TCP as lower transport
>> > - Send keep-alive OPTIONS regularly (which we added in trunk a few weeks
>> > ago)
>> > - Require TCP-interleaved RTP packets to be at least 11 bytes, instead of
>> > 12. (A minimal RTP packet is 12 bytes, but a minimal RTCP packet can be
>> > much smaller, at least as small as 8 bytes.) This could be adjusted with
>> > something like this:
>> >
>> > diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
>> > index 36fe753..8c4c29b 100644
>> > --- a/libavformat/rtsp.c
>> > +++ b/libavformat/rtsp.c
>> > @@ -1735,7 +1735,7 @@ redo:
>> > ?#ifdef DEBUG_RTP_TCP
>> > ? ? dprintf(s, "id=%d len=%d\n", id, len);
>> > ?#endif
>> > - ? ?if (len > buf_size || len < 12)
>> > + ? ?if (len > buf_size || len < 8)
>> > ? ? ? ? goto redo;
>> > ? ? /* get the data */
>> > ? ? ret = url_read_complete(rt->rtsp_hd, buf, len);
>> >
>> >
>> > Luca B, Ronald, any opinions on adjusting this?
>>
>> Only if we actually do something with the RTCP packet. Otherwise
>> ignoring is better.
>
> We do pass the packet on to the rtpdec code, that may or may not react to
> it (e.g. RTCP BYE support). If we "ignore" small packets this way, the
> payload data of the packets are left unread and will show up as garbage
> before receiving the next packet, I'm not sure how tolerant the code
> currently is against such cases. Adjusting this limit down would avoid
> such cases, at least for valid inputs.

Well, valid only for RTCP, not for RTP. It'd be nice to distinguish if we can.

Ronald