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• FFMPEG (libav) I get pts = 0 on every video frame while i decode video file with B-frames

  23 juin 2023, par Yuriy

  I'm developing simple video player.
When i test my application on sample video with B-frames i get message :
[mpeg4 @ 0x556b56585d40] Video uses a non-standard and wasteful way to store B-frames ('packed B-frames'). Consider using the mpeg4_unpack_bframes bitstream filter without encoding but stream copy to fix it.
Wheh i test my application on sample video without B-frames i have no any problem.

  


  I can't synchronize playback with PTS = 0 or random on every B-frame
LOG is below :

  


  


  Format avi, duration 9223372036854775808 us
Sample format:AV_SAMPLE_FMT_FLTP
Video Codec:MPEG-4 part 2 ID:12 bit_rate:15034224
Audio Codec:MP3 (MPEG audio layer 3) ID:86017 bit_rate:320000
input bitrate : 48000
input audio nchanels : 2
input samples in frame per 1ch 1152
alsa : audio device with PCM name : 'default' is used
alsa : PCM state : PREPARED
alsa : set nchannels : 2
alsa : set stereo sound
alsa : set bitrate : 48000
alsa : set nframes per buffer : 64
alsa : set period time for buffer(in useconds) : 1333
breakpointstart of frame decoding loop
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
m_syncmaster:eUndef3 eVideoMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
m_syncmaster eAudioMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
m_syncmaster eAudioMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
m_syncmaster eAudioMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
......
m_syncmaster eAudioMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
[mpeg4 @ 0x556b56585d40] Video uses a non-standard and wasteful way to store B-frames ('packed B-frames'). Consider using the mpeg4_unpack_bframes bitstream filter without encoding but stream copy to fix it.
read_frame : got video frame format 0 size 1448637632
convert video Frame I (1) pts 0 dts 1 key_frame 1 delay 0.000000 data size 6220800
read_frame : Last video frame format -1 size 1448637632
read_frame : got audio frame format AV_SAMPLE_FMT_FLTP size 4608
m_syncmaster eAudioMaster
Last audio frame format AV_SAMPLE_FMT_NONE size 0
read_frame : got video frame format 0 size 1448637632
convert video Frame B (2) pts 0 dts 2 key_frame 0 delay 0.000000 data size 6220800
read_frame : Last video frame format -1 size 1448637632

  


  


  How can i fix Iit ?
FFMPEG(libav) version 5.1

  


  I try to google this problem and have found a hint : mpeg4_unpack_bframe, but I don't understand how to implement it.

  


• Naming FFMpeg output file after Container Conversion

  29 juin 2023, par Clippers

  I repackage .mkv and .avi to .mp4 using this command.

  


  setlocal enabledelayedexpansion
for %%a in ( "*.mkv" "*.avi" ) do (
(ffmpeg -i "%%a" -c:v copy -c:a copy -y "%%a.mp4"))


  


  The problem is my output files get named filename.mkv.mp4 or filename.avi.mp4 How do I declude the .mkv/.avi part ?

  


  I've found a batch file that finds filenames containing any keyboard key or combination and removes them, which I provide for anyone who needs to remove/replace characters appearing anywhere in a filename.

  


  I use this batch file to remove the .mkv, .avi which appear anywhere in the filename. But.. a space is left in place of .mkv. I recently found the fix for removing the .mkv not leaving a space, which is at the bottom.

  


  setlocal enabledelayedexpansion
for /f "usebackq delims=" %%N in (`dir /s /b`) do 
(
set var=%%~nN
set var=!var:^.mkv= !
set var=!var:%%= !

if not "!var!"=="%%~nN" (
  if not exist "%%~dpN!var!%%~xN" (
      echo "%%N" --^> "!var!%%~xN"
      ren "%%N" "!var!%%~xN"
    ) else (
      echo File "!var!%%~xN" ^(from %%N^) already 
exists.
    )
  )
)


  


  To remove .mkv and not replace it with a space, all that I had to do was to remove the space right before the first occurrence of explanation point.
By the way, this file will not remove the last period in a file name. Also, if you want to delete more keyboard keys, then add more lines right below them. Two lines for each thing you want removed. You can use any keyboard character. For example, to remove .mkv not leaving a space ; and, replace all & with a space, use :

  


  set var=!var:^.mkv=!
set var=!var:%%= !
set var=!var:^&= !
set var=!var:%%= !


  


  Finally, I didn't write this script but since I did not document it's originator, I don't want to take credit for its authenticity.

  


• .mov file not playing on Mac [closed]

  15 août 2023, par evorg88

  I have exported a number of videos from a Bosch CCTV system. These cover a period of 24 hours, and are split into approx. 16 minute clips @ 650MB. The files outputted are of the .mov format.

  


  When I try to open any of these clips, the following happens :

  


  

  • Windows Media Player opens and presents a still image of the first frame, then closes after approx. 3 seconds. It doesn’t allow me to scroll through the video whilst it’s attempting to play.

  


  • QuickTime Player does the same as windows media player.

  


  • VLC allows me to scroll through the video, but doesn’t actually start playing. This also closes after a few seconds.

  


  


  All of the files show approx. 650MB file size, but zero second duration.

  


  I tried using VLC to convert one of the files to an MP4 type, and now it plays without issue !

  


  Note, I then tried converting the original .mov file to MP4 using ffmpeg due to its batch conversion capability, but this failed to output a file that would play.

  


  I understand I’ll need to convert all of the files to MP4 now (although I can’t understand the reason why), but it looks like VLC makes you convert them one at a time.

  


  If anybody can help me out with where I’m going wrong, or advice on a batch conversion method for Mac (M1) it would be hugely appreciated !

  


  Thanks !