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• Convert Black to Transparency in FFMPEG

  12 février 2019, par Kapitano

  I have a sequence of BMP images, which I’m concatenating to an MPNG video file, with this FFMPEG code :

  ffmpeg -f image2 -framerate 12 -i "Frame_%d.bmp" -c:v png "Video.avi"

  I want to replace all black pixels with a transparency in the alpha layer, so it can be laid over other videos in an editor. The following code doesn’t work :

  ffmpeg -f image2 -framerate 12 -i "Frame_%d.bmp" -filter_complex "[0:v]colorkey=0x000000:0.01:0.0[BlackToTransparancy]" -map [BlackToTransparancy] -c:v png "Video.avi"

  As requested, here’s the full log :

  ffmpeg version N-93020-g3224d6691c Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20181201
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
    libavutil      56. 26.100 / 56. 26.100
  
    libavcodec     58. 44.100 / 58. 44.100
  
    libavformat    58. 26.100 / 58. 26.100
  
    libavdevice    58.  6.101 / 58.  6.101
  
    libavfilter     7. 48.100 /  7. 48.100
  
    libswscale      5.  4.100 /  5.  4.100
  
    libswresample   3.  4.100 /  3.  4.100
  
    libpostproc    55.  4.100 / 55.  4.100
  
  Input #0, image2, from 'D:\ReadOut_Process\Test\Test__Frame_%d.bmp':
  
    Duration: 00:00:16.83, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: bmp, bgra, 1280x720, 12 tbr, 12 tbn, 12 tbc
  
  Stream mapping:
  
    Stream #0:0 (bmp) -> colorkey
  
    colorkey -> Stream #0:0 (png)
  
  Press [q] to stop, [?] for help
  
  Output #0, avi, to 'D:\ReadOut_Process\Test\Test__Scribe.avi':
  
    Metadata:
  
      ISFT            : Lavf58.26.100
  
      Stream #0:0: Video: png (MPNG / 0x474E504D), rgba, 1280x720, q=2-31, 200 kb/s, 12 fps, 12 tbn, 12 tbc
  
      Metadata:
  
        encoder         : Lavc58.44.100 png
  
  frame=   34 fps=0.0 q=-0.0 size=     774kB time=00:00:02.16 bitrate=2924.7kbits/s speed=4.21x    
  
  frame=   65 fps= 64 q=-0.0 size=    1798kB time=00:00:04.75 bitrate=3100.1kbits/s speed=4.66x    
  
  frame=   95 fps= 62 q=-0.0 size=    3078kB time=00:00:07.25 bitrate=3477.4kbits/s speed=4.76x    
  
  frame=  124 fps= 61 q=-0.0 size=    4358kB time=00:00:09.66 bitrate=3692.8kbits/s speed=4.76x    
  
  frame=  155 fps= 61 q=-0.0 size=    6150kB time=00:00:12.25 bitrate=4112.4kbits/s speed=4.83x    
  
  frame=  185 fps= 61 q=-0.0 size=    7686kB time=00:00:14.75 bitrate=4268.5kbits/s speed=4.84x    
  
  frame=  202 fps= 58 q=-0.0 Lsize=    9187kB time=00:00:16.83 bitrate=4470.8kbits/s speed=4.83x    
  
  video:9176kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.112806%

  The BMPs are too large to upload, but here’s a link to a section of a typical one : https://pasteboard.co/I0RzfjI.bmp

  Can it be done ?

• FFMPEG segment creates black frame in the beginning - and key_frame looks offset [closed]

  30 septembre 2022, par jackyroo

  I'm trying to split a video using ffmpeg segment :

  


  ffmpeg -r 60 -accurate_seek -I input.mov -map 0:a? -map 0:v? -codec copy -reset_timestamps 1 -map_metadata 0 -avoid_negative_ts 1 -f segment output_%%03d.mov -y -loglevel debug

  


  The problem with this approach is that the first split segment has 2 black frames at the beginning, while the consecutive ones are fine.

  


  I cannot figure out why, and I'm genuinely lost in this process.

  


  I've also tried specifying -force_key_frames but it makes no difference at all.

  


  Then I found something interesting by comparing keyframes of the original video and the first split chunk using this command :

  


  ffprobe -select_streams v -skip_frame nokey -show_frames -v quiet input.mov

  


  Original Video KeyFrames
The first keyframe of the original video looks fine :

  


  [FRAME]
media_type=video
stream_index=0
key_frame=1
pts=0
pts_time=0.000000
pkt_dts=127488
pkt_dts_time=8.300000
best_effort_timestamp=0
best_effort_timestamp_time=0.000000
pkt_duration=256
pkt_duration_time=0.016667
duration=256
duration_time=0.016667
pkt_pos=40
pkt_size=128838
width=1420
height=2000
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=0
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
color_range=unknown
color_space=unknown
color_primaries=unknown
color_transfer=unknown
chroma_location=left
[SIDE_DATA]
side_data_type=H.26[45] User Data Unregistered SEI message
[/SIDE_DATA]
[/FRAME]


  


  Split Video - First Chunk Keyframes

  


  On the other hand, it seems like the first keyframe of the chunk (the one with the two added black frames in the beginning) gets shifted !

  


  [FRAME]
media_type=video
stream_index=1
key_frame=1
pts=507
pts_time=0.033008
pkt_dts=N/A
pkt_dts_time=N/A
best_effort_timestamp=507
best_effort_timestamp_time=0.033008
pkt_duration=256
pkt_duration_time=0.016667
duration=256
duration_time=0.016667
pkt_pos=40
pkt_size=128838
width=1420
height=2000
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=0
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
color_range=unknown
color_space=unknown
color_primaries=unknown
color_transfer=unknown
chroma_location=left
[SIDE_DATA]
side_data_type=H.26[45] User Data Unregistered SEI message
[/SIDE_DATA]
[/FRAME]


  


  Might this be the cause of the two black frames at the beginning ?

  


  The following is the first (and only) keyframe of the second chunk, and it looks fine :

  


  [FRAME]
media_type=video
stream_index=1
key_frame=1
pts=0
pts_time=0.000000
pkt_dts=N/A
pkt_dts_time=N/A
best_effort_timestamp=0
best_effort_timestamp_time=0.000000
pkt_duration=256
pkt_duration_time=0.016667
duration=256
duration_time=0.016667
pkt_pos=40
pkt_size=158598
width=1420
height=2000
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=0
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
color_range=unknown
color_space=unknown
color_primaries=unknown
color_transfer=unknown
chroma_location=left
[/FRAME]


  


  Please help me spreading some light over this...

  


  Thanks !

  


• Changing video color to Black&White and Blue and RGB [on hold]

  2 janvier 2016, par drorAlfasi

  I am using Dranger - ffmpeg and SDL Tutorial and I am trying to change video format to RGB, then when pressing W key transfer to BW and then on C to bring it back to colour.
  After bringing it back to colour while pressing on B button the stream need to change to Blue colour.
  I can’t success to convert it to RGB.
  Any help ?

  I am using tutorial 07 of Dranger.
  Link to Dranger C code