Recherche avancée

Sur d’autres sites (4228)

• ffmpeg mp3 chunk to wav chunk adds gap in the start of the audio

  13 décembre 2023, par 1Mayur

  I have an mp3 streaming from a URL, I save the chunks in 1024 byes buffer size.
After I get all the chunks, I'm using ffmpeg to convert the incoming mp3 chunk (22050 mono) to a wav chunk.

  


  When I open/play the wav chunk I see that there is an empty gap at the start of every chunk.

  


  here is the code I'm running in Python subprocess in a loop for all the saved chunks

  


  subprocess.run(["ffmpeg", "-i",
    f"{Path.cwd()}/input/{path}",
    f"{Path.cwd()}/temp_output/{path.replace('.mp3', '')}.wav"
])


  


  here is the output in the terminal

  


  processing: test-016.mp3
ffmpeg version 6.0 Copyright (c) 2000-2023 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.0.40.1)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/6.0_1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox
  libavutil      58.  2.100 / 58.  2.100
  libavcodec     60.  3.100 / 60.  3.100
  libavformat    60.  3.100 / 60.  3.100
  libavdevice    60.  1.100 / 60.  1.100
  libavfilter     9.  3.100 /  9.  3.100
  libswscale      7.  1.100 /  7.  1.100
  libswresample   4. 10.100 /  4. 10.100
  libpostproc    57.  1.100 / 57.  1.100
[mp3 @ 0x7fd48e104480] Format mp3 detected only with low score of 25, misdetection possible!
[mp3 @ 0x7fd48e104480] Skipping 463 bytes of junk at 0.
[mp3 @ 0x7fd48e104480] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from '/Users/mayur/Projects/input/test-016.mp3':
  Duration: 00:00:00.39, start: 0.000000, bitrate: 169 kb/s
  Stream #0:0: Audio: mp3, 22050 Hz, mono, fltp, 160 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (mp3float) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, wav, to '/Users/mayur/Projects/temp_output/test-016.wav':
  Metadata:
    ISFT            : Lavf60.3.100
  Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 22050 Hz, mono, s16, 352 kb/s
    Metadata:
      encoder         : Lavc60.3.100 pcm_s16le
size=      17kB time=00:00:00.36 bitrate= 379.7kbits/s speed= 253x    
video:0kB audio:17kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.451389%


  


  I tried the pydub as well and faced similar issue.

  


• Trouble trimming video by frame number with ffmpeg

  8 décembre 2023, par jgore200377

  I want to trim/split a video with ffmpeg using frames. The reason why is because I am using a Shot Transition Detection model which returns a probability of transition for every frame in the video.

  


  Using timestamps to cut the video has yielded bad results as the precision is not 100%.

  


  Ive tried this command which just outputs the entire video which is DEFINITELY not what I want

  


  ffmpeg -i video.mp4 -vf "trim=start_frame=100:end_frame=200,setpts=PTS-STARTPTS" -c:a copy output.mp4


  


  Ive also tried using python bindings with ffmpeg-python

  


  import ffmpeg

input_file = ffmpeg.input('video.mp4')
output_file = ffmpeg.output(input_file.trim(start_frame=1300, end_frame=1500), 'test_output.mp4')
ffmpeg.run(output_file)


  


  This doesnt work either and outputs a video with half of it being still with unpredictable length

  


  ---

  


  Ive visited some other sites but none seem to have this nailed down and it would be much appreciated if someone can answer how to use frames to trim/split a video with ffmpeg.

  


• Ffmpeg dynamic cropping for every frame

  25 janvier 2024, par Aman Mehta

  I have different crop parameters for every frame. I was using sendcmd but apparently, that is not working.

  


  This is the format of my sendcmd file

  


  0.00 crop 'w=466:h=432:x=1373:y=336';
0.02 crop 'w=324:h=382:x=277:y=693';
0.03 crop 'w=304:h=332:x=1364:y=794';
0.05 crop 'w=348:h=448:x=1500:y=966';
0.07 crop 'w=466:h=412:x=794:y=193';
0.08 crop 'w=390:h=502:x=1425:y=813';


  


  And I am running this command

  


  ffmpeg -ss 0 -t 1 -i Demo.mp4 -filter_complex "[0:v]sendcmd=f=crop_parameters.txt[video]" -map "[video]" output_%03d.png


  


  These are the logs coming from FFmpeg

  


  [Parsed_sendcmd_0 @ 0x6000016709a0] [expr] interval #0 start_ts:0.000000 end_ts:9223372036854.775391 ts:0.083367
[Parsed_sendcmd_0 @ 0x6000016709a0] [expr] interval #1 start_ts:0.040000 end_ts:9223372036854.775391 ts:0.083367
[Parsed_sendcmd_0 @ 0x6000016709a0] [enter+expr] interval #2 start_ts:0.080000 end_ts:9223372036854.775391 ts:0.083367
[Parsed_sendcmd_0 @ 0x6000016709a0] Processing command #0 target:crop command:w arg:147
[Parsed_sendcmd_0 @ 0x6000016709a0] Command reply for command #0: ret:Function not implemented res:
[Parsed_sendcmd_0 @ 0x6000016709a0] Processing command #1 target:crop command:h arg:258
[Parsed_sendcmd_0 @ 0x6000016709a0] Command reply for command #1: ret:Function not implemented res:
[Parsed_sendcmd_0 @ 0x6000016709a0] Processing command #2 target:crop command:x arg:928
[Parsed_sendcmd_0 @ 0x6000016709a0] Command reply for command #2: ret:Function not implemented res:
[Parsed_sendcmd_0 @ 0x6000016709a0] Processing command #3 target:crop command:y arg:102
[Parsed_sendcmd_0 @ 0x6000016709a0] Command reply for command #3: ret:Function not implemented res:


  


  It resulted in no cropping of the video, it just gives the exact same frame