ffmpeg with copy codecs is not guaranteed to contain number of frames in output #44
Description
Noticed this when using ffmpeg installed from apt, when vcodec and acodec are copy, the frame= XXX line does not appear in the output, causing api like read_video to fail. The actual output of the ffmpeg -nostdin -i videofile.m4v -acodec copy -vcodec copy -f null - call is
ffmpeg version 6.1-3 Copyright (c) 2000-2023 the FFmpeg developers
built with gcc 13 (Debian 13.2.0-5)
configuration: --prefix=/usr --extra-version=3 --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-libglslang --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librist --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 --disable-sndio --enable-libjxl --enable-pocketsphinx --enable-librsvg --enable-libvpl --disable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libsvtav1 --enable-libx264 --enable-libplacebo --enable-librav1e --enable-shared
libavutil 58. 29.100 / 58. 29.100
libavcodec 60. 31.102 / 60. 31.102
libavformat 60. 16.100 / 60. 16.100
libavdevice 60. 3.100 / 60. 3.100
libavfilter 9. 12.100 / 9. 12.100
libswscale 7. 5.100 / 7. 5.100
libswresample 4. 12.100 / 4. 12.100
libpostproc 57. 3.100 / 57. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'videofile.m4v':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
creation_time : 2023-04-26T22:39:08.000000Z
Duration: 00:00:16.50, start: 0.000000, bitrate: 5329 kb/s
Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, progressive), 640x480, 5114 kb/s, 30.10 fps, 29.67 tbr, 90k tbn (default)
Metadata:
creation_time : 2023-04-26T22:39:08.000000Z
handler_name : ISO Media file produced by Corp Inc. Created on: 04/26/2023.
vendor_id : [0][0][0][0]
Side data:
displaymatrix: rotation of 90.00 degrees
Stream #0:1[0x2](und): Data: none (mett / 0x7474656D), 20 kb/s (default)
Metadata:
creation_time : 2023-04-26T22:39:08.000000Z
handler_name : ISO Media file produced by Corp Inc. Created on: 04/26/2023.
Stream #0:2[0x3](und): Data: none (mett / 0x7474656D), 64 kb/s (default)
Metadata:
creation_time : 2023-04-26T22:39:08.000000Z
handler_name : ISO Media file produced by Corp Inc. Created on: 04/26/2023.
Stream #0:3[0x4](und): Data: none (mett / 0x7474656D), 64 kb/s (default)
Metadata:
creation_time : 2023-04-26T22:39:08.000000Z
handler_name : ISO Media file produced by Corp Inc. Created on: 04/26/2023.
Output #0, null, to 'pipe:':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
encoder : Lavf60.16.100
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, progressive), 640x480, q=2-31, 5114 kb/s, 30.10 fps, 29.67 tbr, 90k tbn (default)
Metadata:
creation_time : 2023-04-26T22:39:08.000000Z
handler_name : ISO Media file produced by Corp Inc. Created on: 04/26/2023.
vendor_id : [0][0][0][0]
Side data:
displaymatrix: rotation of 90.00 degrees
Stream mapping:
Stream #0:0 -> #0:0 (copy)
[out#0/null @ 0x55bbe6083100] video:10287kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
size=N/A time=00:00:16.47 bitrate=N/A speed=2.13e+03x