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• flacdec : drop unnecessary assert

  15 mai 2013, par Luca Barbato

  flacdec : drop unnecessary assert
  The condition cannot happen anymore.
  

  • [DH] libavcodec/flacdec.c

• ffmpeg convert mov to mp4 without reduction of bit rate

  17 février 2021, par connor449

  I am trying to convert a mov video to mp4, but I don't want any compression to happen. I recorded it with Quicktime on a Mac and did so with maximum, uncompressed quality. When I run ffmpeg -i. I get :

  


      Stream #0:0(und): Video: prores (apcn / 0x6E637061), yuv422p10le(bt709), 1280x720, 72073 kb/s, 30.09 fps, 30 tbr, 30k tbn, 30k tbc (default)



  


  Note the kb/s is 72,073. I want to preserve this bit rate.

  


  I've tried a few different conversion commands, including :

  


  ffmpeg -i input.mov output.mp4


  


  and :

  


  ffmpeg -i input.mov -qscale 0 output.mp4



  


  Both work, but both result in a loss of bit rate. See info on the results of both

  


      Stream #0:0(und): Video: h264 (High 4:2:2) (avc1 / 0x31637661), yuv422p, 1280x720, 4569 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)


  


  How do I convert to mp4 and still have 72,000 kb/s ? Is this possible ?

  


• Drop packets instead of causing DTS error

  26 août 2020, par ottpeter

  I have 2 ffmpeg instances which are going through a buffer that is written in C.

  


  One of the ffmpeg instance is creating an FLV output and sending it to a TCP socket, which is connected to the C program. The C is filling up an array, then sends the packets to the other ffmpeg instance.

  


  The point is that the first ffmpeg instance can loose connection, and can be restarted.

  


  The other ffmpeg instance looks something like this :

  


  ffmpeg \
    -re \
    -fflags +igndts \
    -fflags flush_packets \
    -fflags discardcorrupt \
    -r 25 \ \
    -i $INPUT_VIDEO_STREAM \
    -safe 0 \
    -i music.txt \
    -fflags +genpts \
    -c:a mp3 \
    -b:a 320k \
    -c:v copy \
    -frame_drop_threshold 1.0
    -preset ultrafast \
    -f flv  rtmp://live.twitch.tv/app/live_KEY \
    -async 1 \
    -vsync 2


  


  The problem is, if I stop the other ffmpeg instance and restart it, I will get "Packet lost" error, and after, I will get a bunch of Non-monotonous DTS in output stream errors.

  


  


  [flv @ 0x55acf23632a0] Packet mismatch -1135911011 34757 9695626ate=1560.2kbits/s speed= 1x

  


  


  


  ...
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19080 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19120 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19160 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19200 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19240 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19280 ; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0 ; previous : 62560, current : 19320 ; changing to 62560. This may result in incorrect timestamps in the output file.
...

  


  


  What I would like to happen is to continue playing the mp3 and drop the bad video packages, the video clip can be cut and the new clip can start playing. Even that would be OK if video is behaving strange for some seconds, but stream need to be continuous.

  


  Things I already tried :

  


  

  • several async / vsync options (vsync 1, vsync 2, vsync drop)

  


  • "-fflags +igndts", removing this option, adding it to the output instead

  


  • -fflags +genpts

  


  • to set probesize to 32

  


  • fflags discardcorrupt

  


  


  I also started to write a setpts filter, but couldn't figure out the syntax

  


  How can I stream the mp3 list that way that the video timestamps are not continuous, packet loss will happen sometimes ?