I have a video.mp4 which I need to convert losslessly into a sequence of images.
I used
ffmpeg -i input.mp4 $filename%05d.tiff
but I get a lot (thousands) of duplicated frames. What are they? is it possible to avoid that ffmpeg exports them? I had to stop the operation because it was taking forever.
The video file:
codec: H265 – MPEG-4 AVC (part 10) (avc1)
Encoder: Lavf58.29.100
FPS: 70.476432
resolution: 1824 x 1216
Duration: 0m31s
Full output from ffmpeg (I use Linux):
$ ffmpeg -i input.mp4 $filename%05d.tiff
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
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
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
Duration: 00:00:31.88, start: 0.000000, bitrate: 746 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1824x1216, 741 kb/s, 70.48 fps, 1k tbr, 90k tbn, 2k tbc (default)
Metadata:
handler_name : VideoHandler
vendor_id : [0][0][0][0]
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> tiff (native))
Press [q] to stop, [?] for help
Output #0, image2, to '%05d.tiff':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.76.100
Stream #0:0(und): Video: tiff, yuv420p(progressive), 1824x1216, q=2-31, 200 kb/s, 1k fps, 1k tbn (default)
Metadata:
handler_name : VideoHandler
vendor_id : [0][0][0][0]
encoder : Lavc58.134.100 tiff
More than 1000 frames duplicatedN/A time=00:00:01.04 bitrate=N/A dup=976 drop=0 speed=0.0308x
More than 10000 frames duplicated/A time=00:00:10.74 bitrate=N/A dup=9989 drop=0 speed=0.0265x
frame=17673 fps= 26 q=-0.0 Lsize=N/A time=00:00:17.67 bitrate=N/A dup=16428 drop=0 speed=0.0262x
After trying different options, I found 3 alternatives that achieve the same results. I give details below.
Option 1 (source)
Comment: it uses variable frame-rate mode.
Command: ffmpeg -i input.mp4 -vf mpdecimate -vsync vfr $filename%05d.tiff
Result: it works. The video is exported as 2245 TIFF images (~6.2GB) and no messages about duplicate frames.
Option 2 (source)
Comment: it retimes the frames using the setpts filter.
Command: ffmpeg -i input.mp4 -vf mpdecimate,setpts=N/24/TB -vsync vfr $filename%05d.tiff
Result: it works. The video is exported as 2245 TIFF images (~6.2GB) and no messages about duplicate frames. According to the question in the source, the resulting framerate is 24 FPS (as requested by the OP), but this is not what I need. I need to respect the FPS of the original video (if possible).
Option 3 (source)
Comment: This keeps 1:1 correspondence between input and output frames.
Command: ffmpeg -i input.mp4 -vsync passthrough $filename%05d.tiff
Result: it works. The video is exported as 2246 TIFF images (~6.2GB) and no messages about duplicate frames.
The strange thing (to me anyway) is that all 3 options produce exactly the same TIFF files, each one with a size of 2.8 MiB (I even compared a couple of random pairs by contents, and the files are actually identical, except that option 3 generates 1 more file than options 1 and 2).
