[FFmpeg-trac] #4320(undetermined:new): Incorrect work with SoX pipe

FFmpeg trac at avcodec.org
Sat Mar 19 07:26:56 CET 2016

#4320: Incorrect work with SoX pipe
             Reporter:  Ilya87       |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:               |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0

Comment (by Ilya87):

 Tried with the ffmpeg 3.0. In the beginning I thought this problem is
 connected somehow with thread_que_size, but even the command
 ffmpeg -thread_queue_size 512 -y -framerate 30 -video_size 1280x720 -f
 x11grab -i :0.0+0,0 -f alsa -i looprec -c:v libx264 -preset veryfast
 -maxrate 3500k -b:v 3000k -threads 2 -bufsize 3968k -vf "format=yuv420p"
 -g 60 -c:a aac -b:a 160k 123.mkv
 still shows warning message
 [alsa @ 0x564cc04019c0] Thread message queue blocking; consider raising
 the thread_queue_size option (current value: 8)
 But I see No framedrop and capture fps is 30. And audio and video is

 Recording system sound with ffmpeg and mic using sox leads to the
 audio/video desynchronization approximately 0.8 sec. Video capture speed
 became 30 fps from 745 (3 x264 threads) to 1145 (1 x264 thread) captured
 frame, 28-29 fps before.

Ticket URL: <https://trac.ffmpeg.org/ticket/4320#comment:2>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker

More information about the FFmpeg-trac mailing list