[FFmpeg-trac] #928(undetermined:new): ffmpeg libdc1394 camera live mpeg streaming stops a specific frame number

[FFmpeg]

#928: ffmpeg libdc1394 camera live mpeg streaming stops a specific frame number
-------------------------------------+-------------------------------------
             Reporter:  Zax          |                     Type:  defect
               Status:  new          |                 Priority:  minor
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  libdc1394    |               Blocked By:
  ffserver live streaming            |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I was trying to stream live video from a dc1394 camera by using ffmpeg and
 ffserver. I was successful in streaming the video; however, the stream
 freezes/stops/hangs after a specific time (00:02:23.06) or frame (2146).

 I have tried to debug the problem and noticed that after the 2146th frame
 "vdelta" in "do_video_out" at "ffmpeg.c" goes negative. Moreover, each
 frame increment causes it to decrement further. The reason vdelta goes
 negative is "ost->sync_ist->pts" of input variable "const OutputStream
 *ost" in do_video_out changes sign.

 So, I have made some modifications in "do_video_out" and "get_sync_ipts"
 and temporarily solved the negative vdelta problem. You can find the
 changed functions in the attachment.

 Though I have solved my problem, the bug ("ost->sync_ist->pts" goes
 negative) still exits. I hope my comments are helpful.


 ----

 Here is my ffmpeg commands and ffserver conf file.

 {{{
 # ffmpeg -loglevel debug -v verbose -f libdc1394 -i hw:0,0 -vcodec mpeg4
 -b:v 10000k -bufsize 150000k -r 5 http://127.0.0.1:8090/feed1.ffm
 }}}

 {{{
 # ffserver -loglevel debug -f ffs.conf
 }}}


 {{{
 Port 8090
 # bind to all IPs aliased or not
 BindAddress 0.0.0.0
 # max number of simultaneous clients
 MaxClients 4
 # max bandwidth per-client (kb/s)
 MaxBandwidth 10000000 s
 # Suppress that if you want to launch ffserver as a daemon.
 NoDaemon

 <Feed feed1.ffm>
         File /tmp/feed1.ffm
         FileMaxSize  2000M
         ACL allow 127.0.0.1
 </Feed>

 # mpeg
 <Stream test.mpg>
         # the source feed
         Feed feed1.ffm

         # the output stream format - FLV = FLash Video
         Format  mpegts
         VideoCodec mpeg4

         AVOptionVideo   maxrate 1000000k
         AVOptionVideo   qmin    1
         AVOptionVideo   qmax    31
         AVOptionVideo   bufsize 100000k

         # this must match the ffmpeg -r argument
         VideoFrameRate 15
         VideoSize 320x240

         StartSendOnKey

         VideoGopSize 20
         VideoHighQuality
         Video4MotionVector

         Strict -1

         # this sets how many seconds in past to start
         PreRoll 0

         # don't have audio
         Noaudio

         ACL allow localhost
         ACL allow 192.168.0.0 192.168.255.255
 </Stream>

 <Stream stat.html>
 Format status
 ACL allow localhost
 ACL allow 192.168.0.0 192.168.255.255
 </Stream>
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/928>
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