FFMpeg reports wrong video size ?

[alexander121]

Hello,
i test FFMpeg with a sample MP2 file and it seems to report wrong size.

It says that the video has a size of 352x576 while it propably is 576x352.

Am i doing something wrong ?

The sample is one of the samples that can be downloaded from ffmpeg's site.

c:\1>ffmpeg -i "samples\harry-part.mp2" 2> harry.txt

c:\1>type harry.txt
ffmpeg version N-83657-g7e4f32f Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 6.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  libavutil      55. 47.100 / 55. 47.100
  libavcodec     57. 81.100 / 57. 81.100
  libavformat    57. 66.102 / 57. 66.102
  libavdevice    57.  2.100 / 57.  2.100
  libavfilter     6. 74.100 /  6. 74.100
  libswscale      4.  3.101 /  4.  3.101
  libswresample   2.  4.100 /  2.  4.100
  libpostproc    54.  2.100 / 54.  2.100
[mpegts @ 03d77a00] PES packet size mismatch
    Last message repeated 1 times
Input #0, mpegts, from 'samples\harry-part.mp2':
  Duration: 00:00:35.16, start: 0.659644, bitrate: 4363 kb/s
  Program 1
    Stream #0:0[0x1023]: Audio: mp2 ([3][0][0][0] / 0x0003), 44100 Hz, stereo, s16p, 224 kb/s
    Stream #0:1[0x1022]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, top first), 352x576 [SAR 24:11 DAR 4:3], 4000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc

[poisondeathray]

It's correct

The encoded frame size is 352x576 . But the Display Aspect Ratio is 4:3. So it "stretches" to 4:3 on playback. How it gets resized during playback depends on the player specifics and settings. Most would probably display it as 768x576

Notice it says the DAR is 4:3, but the SAR (or sample aspect ratio) is 24:11 . You can think of "SAR" as the same thing as PAR (or pixel aspect ratio) . It's just different naming conventions

4/3 = 352/576 * 24/11

[Cornucopia]

Agreed. That used to be a common frame size in DVD days for lower resolution/bitrate material (e.g. VHS sourced). It is also known as 1/2 D1 (d1 being 704 or 720 x 480/576). Its even part of the DVD spec.

Scott

[alexander121]

thanks that was very helpful !