Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

• FFmpeg -ss parameter is the video duration, Output file is empty

  16 avril, par noun nil

  The main function is to obtain the corresponding video frame based on the input seconds.Before processing, the duration of the video will be obtained to determine whether the input is within the duration range of the video. If so, the corresponding instruction will be executed.

  > ffprobe input.mp4
    ...
    Duration: 00:00:28.05, start: 0.000000, bitrate: 1136 kb/s
  

  > ffmpeg -ss 00:00:28 -i input.mp4 -frames:v 1 output.png
   ffmpeg version 7.0 Copyright (c) 2000-2024 the FFmpeg developers
    built with Apple clang version 15.0.0 (clang-1500.3.9.4)
    configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.0 --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-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --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-libopenvino --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
    libavutil      59.  8.100 / 59.  8.100
    libavcodec     61.  3.100 / 61.  3.100
    libavformat    61.  1.100 / 61.  1.100
    libavdevice    61.  1.100 / 61.  1.100
    libavfilter    10.  1.100 / 10.  1.100
    libswscale      8.  1.100 /  8.  1.100
    libswresample   5.  1.100 /  5.  1.100
    libpostproc    58.  1.100 / 58.  1.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf58.29.100
      description     : Packed by Bilibili XCoder v2.0.2
    Duration: 00:00:28.05, start: 0.000000, bitrate: 1136 kb/s
    Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 720x1280 [SAR 1:1 DAR 9:16], 1005 kb/s, 25.27 fps, 25.25 tbr, 16k tbn (default)
        Metadata:
          handler_name    : VideoHandler
          vendor_id       : [0][0][0][0]
    Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
        Metadata:
          handler_name    : SoundHandler
          vendor_id       : [0][0][0][0]
  Stream mapping:
    Stream #0:0 -> #0:0 (h264 (native) -> png (native))
  Press [q] to stop, [?] for help
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e48000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e58000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e68000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e78000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e88000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110e98000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110ea8000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110eb8000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [swscaler @ 0x1187a0000] [swscaler @ 0x110ec8000] No accelerated colorspace conversion found from yuv420p to rgb24.
  [vost#0:0/png @ 0x12ce06840] No filtered frames for output stream, trying to initialize anyway.
  Output #0, image2, to 'output.png':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      description     : Packed by Bilibili XCoder v2.0.2
      encoder         : Lavf61.1.100
    Stream #0:0(und): Video: png, rgb24(progressive), 720x1280 [SAR 1:1 DAR 9:16], q=2-31, 200 kb/s, 25.25 fps, 16k tbn (default)
        Metadata:
          handler_name    : VideoHandler
          vendor_id       : [0][0][0][0]
          encoder         : Lavc61.3.100 png
  [out#0/image2 @ 0x600000e983c0] video:0KiB audio:0KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown
  [out#0/image2 @ 0x600000e983c0] Output file is empty, nothing was encoded(check -ss / -t / -frames parameters if used)
  frame=    0 fps=0.0 q=0.0 Lsize=N/A time=N/A bitrate=N/A speed=N/A    
  
  

  -ss 00:00:28 within the video duration range, but still cannot obtain frames...

  -ss 00:00:27 Can obtain video frames

• ffmpeg : Unrecognized option 'alpha_quality'

  16 avril, par László Monda

  I want to make transparent videos work in Safari, which doesn't support WebM for this purpose but only H265 with alpha transparency.

  According to this post, I used Shutter Encoder, but only some of its versions work for this purpose on Mac.

  Instead of using Shutter Encoder on Mac, I want to use ffmpeg on my Linux PC. Shutter Encoder uses the following command in the background:

  ffmpeg -threads 0 -hwaccel none -i input.mov -c:v hevc_videotoolbox -alpha_quality 1 -b:v 1000k -profile:v main -level 5.2 -map v:0 -an -pix_fmt yuva420p -sws_flags bicubic -tag:v hvc1 -metadata creation_time=2024-04-14T14:53:08.734684Z -y output.mp4

  which yields the following output on my PC:

  ffmpeg version 4.4.2-0ubuntu0.22.04.1 Copyright (c) 2000-2021 the FFmpeg developers
    built with gcc 11 (Ubuntu 11.2.0-19ubuntu1)
    configuration: --prefix=/usr --extra-version=0ubuntu0.22.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-librsvg --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
    WARNING: library configuration mismatch
    avcodec     configuration: --prefix=/usr --extra-version=0ubuntu0.22.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-librsvg --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared --enable-version3 --disable-doc --disable-programs --enable-libaribb24 --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libtesseract --enable-libvo_amrwbenc --enable-libsmbclient
    libavutil      56. 70.100 / 56. 70.100
    libavcodec     58.134.100 / 58.134.100
    libavformat    58. 76.100 / 58. 76.100
    libavdevice    58. 13.100 / 58. 13.100
    libavfilter     7.110.100 /  7.110.100
    libswscale      5.  9.100 /  5.  9.100
    libswresample   3.  9.100 /  3.  9.100
    libpostproc    55.  9.100 / 55.  9.100
  Unrecognized option 'alpha_quality'.
  Error splitting the argument list: Option not found
  

  When googling for "Unrecognized option 'alpha_quality'.", there are no results, which I find very odd.

  What's going on, and how can I make ffmpeg work for this purpose without Shutter Encoder?

• How can I convert a ffmpeg command to the ffmpeg-python script ?

  16 avril, par leo87

  I have a ffmpeg command for converting an audio file from .mpt to .aac and then combining it with a .mp4 video file to create a new video file, as shown below. I would like to convert these commands into a ffmpeg-python script.

  ffmpeg -i a.mp4 -vn -acodec copy a.aac
  ffmpeg -i v.mp4 -i a.aac -c:v copy -c:a copy -map 0:v:0 -map 1:a:0 output.mp4
  

  Any suggestions on how to solve this problem please? Thanks in advance.

  I've managed to rewrite the first command in ffmpeg-python (it was easy)

  (
      ffmpeg
      .input(a_input)
      .output('a.aac', acodec='aac')
      .global_args('-report')
      .run()
  )
  

  However, for the second line, I tried the following script but it does NOT work.

  # handles multiple input
  video = ffmpeg.input(v_input)
  audio = ffmpeg.input('a.aac')
  
  # handles multiple -map flags
  output_video = video['v']
  output_audio = audio['a']
  
  (
  ffmpeg
        .filter([video, audio], 'overlay', 10, 10)
        .output(
             output_video,
             output_audio,
             v_out)
         .run(
             capture_stdout=True,
             capture_stderr=True,
         )
  )
  

• Anomaly in raw I420 video generated by GStreamer

  16 avril, par Lea

  Situation

  I'm trying to convert RGBA image data to YUV420P in multiple threads, then send this data to a main thread which splits the data it receives from each thread into separate frames and combines them in order to a video. Currently, I'm using FFmpeg for this task but I've found GStreamer to do a quicker job at colorspace conversion than FFmpeg.

  Problem

  The raw video generated by GStreamer does not match the expectations for YUV 4:2:0 planar video data. To test this, I've made a raw RGBA test video of 3 red 4x4 (16 pixel) frames.

  ffmpeg -f lavfi -i color=color=red -t 3 -r 1 -s 4x4 -f rawvideo -pix_fmt rgba ./input.rgba
  

  

  FFmpeg

  Now, first trying to convert it via FFmpeg as I'm doing it currently:

  ffmpeg -f rawvideo -pix_fmt rgba -s 4x4 -i input.rgba -f rawvideo -pix_fmt yuv420p ./ffmpeg.yuv420p
  

  This creates a 72 byte file => 1.5 bytes per pixel, 24 bytes per frame: As expected for yuv420p data.

  $ hexdump -C ./ffmpeg.yuv420p 
  00000000  51 51 51 51 50 50 50 50  50 50 50 50 50 50 50 50  |QQQQPPPPPPPPPPPP|
  00000010  5b 5b 5b 5b ee ee ee ee  51 51 51 51 50 50 50 50  |[[[[....QQQQPPPP|
  00000020  50 50 50 50 50 50 50 50  5b 5b 5b 5b ee ee ee ee  |PPPPPPPP[[[[....|
  00000030  51 51 51 51 50 50 50 50  50 50 50 50 50 50 50 50  |QQQQPPPPPPPPPPPP|
  00000040  5b 5b 5b 5b ee ee ee ee                           |[[[[....|
  

  GStreamer

  Now trying to do the same via GStreamer, with the I420 format which corresponds to yuv420p as per their documentation:

  gst-launch-1.0 filesrc location=./input.rgba ! rawvideoparse format=rgba width=4 height=4 \
  ! videoconvert ! video/x-raw,format=I420 ! filesink location=./gstreamer.yuv420p
  

  This creates a 96 byte file => 2 bytes per pixel, 32 bytes per frame (?): Unusual for yuv420p data. Additionally, none of the sections match the FFmpeg output, ruling out some kind of padding.

  $ hexdump -C ./gstreamer.yuv420p 
  00000000  50 50 50 50 50 50 50 50  50 50 50 50 50 50 50 50  |PPPPPPPPPPPPPPPP|
  00000010  5a 5a 00 00 5a 5a 00 00  ee ee 00 00 ed ed 00 00  |ZZ..ZZ..........|
  00000020  50 50 50 50 50 50 50 50  50 50 50 50 50 50 50 50  |PPPPPPPPPPPPPPPP|
  00000030  5a 5a 63 6b 5a 5a 77 62  ee ee 78 6d ed ed 2c 20  |ZZckZZwb..xm.., |
  00000040  50 50 50 50 50 50 50 50  50 50 50 50 50 50 50 50  |PPPPPPPPPPPPPPPP|
  00000050  5a 5a 00 00 5a 5a 00 00  ee ee 00 00 ed ed 00 00  |ZZ..ZZ..........|
  

  This output can also not be interpreted correctly as yuv420p by FFmpeg, leading to corrupted frames when trying to do so:

  ffmpeg -f rawvideo -pix_fmt yuv420p -s 4x4 -i gstreamer.yuv420p -f image2 "./%d.png"
  

  

  Solution?

  For my personal problem I need a way to chop up raw I420 video generated by GStreamer into separate frames to work with. However, I would also like to understand why GStreamer behaves this way and which key piece I'm missing here.

  Additional notes

  I've ruled out an issue with the input in GStreamer, as piping it to autovideosink leads to a normal result. I'm also aware of multifilesink, but I would like to avoid writing to disk and rather work with the data directly in buffers.

• How can I decode audio-file with ffmpeg ? [closed]

  16 avril, par skltynve

  I need to decode audio-file in C using library ffmpeg so I have array of numbers. How can I do that?