[FFmpeg-trac] #285(FFmpeg:new): RTSP h264 video stream always reports corrupted macroblock

FFmpeg trac at avcodec.org
Wed Nov 23 20:14:29 CET 2011

#285: RTSP h264 video stream always reports corrupted macroblock
             Reporter:  bovine       |                    Owner:  michael
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  FFmpeg
              Version:  unspecified  |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |

Comment (by Ph0t0n):

 michael is correct - something has definitely been fixed. i just tried git
 version 2c44aed (from 2011-11-21) and i no longer get errors when using
 the camera on my local network.

 With the cameras on the public internet (like the one in the link from my
 previous post), errors still occur and I'm guessing it's due to dropped
 packets. on my 40mbit internet connection at home it gets an error once a
 minute or so, and on my slow connection at work the error rate is hundreds
 per minute. the errors that display due to dropped packets are nearly
 identical to the errors that came from that bug that is now fixed. there's
 not much that can be done about dropped UDP/RTP packets except perhaps
 wait longer and buffer more, but even then, that's probably not going to
 help much.

 vlc handles dropped packets differently than ffplay. i think they do more
 buffering (well you can set the buffer size), and they also drop the
 entire frame instead of passing a corrupted packet to the decoder. so
 instead of getting mpeg4 errors and visual artifacts, you get lower frame

 in my opinion, live rtsp/rtp over the public internet is too unreliable to
 be useful. with tcp visual quality is better, but then you get high
 latency which make video conferencing and live ptz cameras useless. it's
 fine on a local gigabit network, but for internet that's not blazing fast,
 good luck!

 to whomever fixed the udp/rtp bug: hell yeah, you rock!!!!

 draku1a - if you're still having problems after making sure you have the
 latest version of libav, use wireshark or something and check to make sure
 your network is reliable. if you're using a fast local network that
 doesn't drop packets then i have no idea what's going on!

Ticket URL: <http://ffmpeg.org/trac/ffmpeg/ticket/285#comment:19>
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