'ffmpeg -i' print SAR instead of PAR

[jofsey]

Summary of the bug:
If my knowledge is correct, SAR (Storage Aspect Ratio) is the ratio of pixel dimensions. For example, a 640 × 480 video has a SAR of 640/480 = 4:3.

Whereas PAR (Pixel Aspect Ratio) is ratio of pixel height and width, and most of modern videos have square PAR (1:1).

But when I tried to check it with ffmpeg -i or ffprobe, I got square SAR instead of square PAR for all test videos.

How to reproduce:

% ffprobe 3867805782.mp4
ffprobe version 2.0.1 Copyright (c) 2007-2013 the FFmpeg developers
  built on Aug 11 2013 14:52:28 with gcc 4.8.1 (GCC) 20130725 (prerelease)
  configuration: --prefix=/usr --disable-debug --disable-static --enable-avresample --enable-dxva2 --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-pic --enable-postproc --enable-runtime-cpudetect --enable-shared --enable-swresample --enable-vdpau --enable-version3 --enable-x11grab
  libavutil      52. 38.100 / 52. 38.100
  libavcodec     55. 18.102 / 55. 18.102
  libavformat    55. 12.100 / 55. 12.100
  libavdevice    55.  3.100 / 55.  3.100
  libavfilter     3. 79.101 /  3. 79.101
  libavresample   1.  1.  0 /  1.  1.  0
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '3867805782.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.6.100
  Duration: 00:00:07.97, start: 0.000000, bitrate: 428 kb/s
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 309 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 59.94 tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 115 kb/s
    Metadata:
      handler_name    : SoundHandler

[Carl Eugen Hoyos]

SAR .. Sample Aspect Ratio (what you call Pixel Aspect Ratio)
DAR .. Display Aspect Ratio (maybe what you call Storage Aspect Ratio or is that just width/height?)

Imo, it does not make much sense to discuss how FFmpeg calls them, if you have problems with actual display or display on third party software after conversion, please report them!

[Carl Eugen Hoyos]

See also ticket #1776 for a more complete discussion.