Aspect Ratio Not Performing Properly - MP4

Black Hole

May contain traces of nut
I have some MOVs, taken and then exported from an iPad by uploading to iCloud - a very useful side effect being that they get transcoded on the fly (before upload) to MP4 and occupying about one-seventh the space (and a seventh the upload time).

The problem is that when I copy these MP4s to an HDR-FOX, they play at 4:3 instead of 16:9, unless I set the WIDE button to "auto". I used ffmpeg on the command line to change aspect ratio, and appeared to make no difference. I then started looking at MP4Box to do it, and needed to work out the pixel aspect ratios etc, so I had a look at the properties of the original MP4s - and they claim to be 16:9! See below.

Any ideas why this is and what to do about it (without re-encoding)?

Code:
===================== General =====================
Complete name               : G:\test_in.mp4
Format                      : MPEG-4
Format profile              : Base Media / Version 2
Codec Id                    : mp42
File size                   : 79.2 MB
Duration (ms)               : 3mn 39s
Total bitrate               : 3 031 Kbps
Encoded date                : UTC 2016-01-09 07:46:23
Tagged date                 : UTC 2016-01-09 07:48:46

===================== Video =====================
Id                          : 2
Format                      : AVC
Format info                 : Advanced Video Codec
Format profile              : Baseline@L3.1
Use of CABAC                : No
RefFrames                   : 1 frame
Format settings - GOP       : M=1, N=30
Codec Id                    : avc1
Codec info                  : Advanced Video Coding
Duration (ms)               : 3mn 39s
Source_Duration/String      : 3mn 39s
Bitrate                     : 2 966 Kbps
Width                       : 1 280 pixels
Height                      : 720 pixels
Aspect ratio                : 16:9
Framerate mode              : Variable
Framerate                   : 29.970 fps
FrameRate_Minimum/String    : 28.571 fps
FrameRate_Maximum/String    : 30.000 fps
Colorimetry                 : YUV
Colos space                 : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.107
Stream size                 : 77.4 MB (98%)
Source_StreamSize/String    : 77.4 MB (98%)
Title                       : Core Media Video
Encoded date                : UTC 2016-01-09 07:46:23
Tagged date                 : UTC 2016-01-09 07:48:46
colour_primaries            : BT.709
transfer_characteristics    : BT.709
matrix_coefficients         : BT.709

===================== Audio =====================
Id                          : 1
Format                      : AAC
Format info                 : Advanced Audio Codec
Format profile              : LC
Codec Id                    : 40
Duration (ms)               : 3mn 39s
Source_Duration/String      : 3mn 39s
Bitrate mode                : Constant
Bitrate                     : 64.0 Kbps
Channel(s)                  : 2 channels
Channel(s)_Original/String  : 1 channel
ChannelPositions            : Front: C
Sampling rate               : 44.1 KHz
Compression_Mode/String     : Lossy
Stream size                 : 1.64 MB (2%)
Source_StreamSize/String    : 1.64 MB (2%)
Title                       : Core Media Audio
Encoded date                : UTC 2016-01-09 07:46:23
Tagged date                 : UTC 2016-01-09 07:48:46
 
OP
Black Hole

Black Hole

May contain traces of nut
Every media player I've thrown this at on the PC get it right. What's with the sodding Humax? Maybe it's just not worth worrying about.
 
OP
Black Hole

Black Hole

May contain traces of nut
I can't see anything about those:
Code:
HDRFOX4# ffprobe test_in.mp4
ffprobe version 0.10 Copyright (c) 2007-2012 the FFmpeg developers
  built on Feb 29 2012 10:25:07 with gcc 4.2.0 20070124 (prerelease) - BRCM 11ts-20090508
  configuration: --cross-prefix=mipsel-linux- --enable-cross-compile --arch=mipsel --target-os=linux --enable-gpl --enable-libmp3lame --disable-static --enable-shared --disable-asm --prefix=/mod --extra-cflags=-fPIC
  libavutil      51. 34.101 / 51. 34.101
  libavcodec     53. 60.100 / 53. 60.100
  libavformat    53. 31.100 / 53. 31.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 60.100 /  2. 60.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_in.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp41mp42isom
    creation_time   : 2016-01-09 07:46:23
  Duration: 00:03:39.05, start: 0.000000, bitrate: 3031 kb/s
    Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, s16, 62 kb/s
    Metadata:
      creation_time   : 2016-01-09 07:46:23
      handler_name    : Core Media Audio
    Stream #0:1(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, 2965 kb/s, 29.96 fps, 29.97 tbr, 600 tbn, 1200 tbc
    Metadata:
      creation_time   : 2016-01-09 07:46:23
      handler_name    : Core Media Video

HDRFOX4#
 
OP
Black Hole

Black Hole

May contain traces of nut
Anybody got any more ideas? If nothing else, it will help to further characterise the performance of the Humax codecs.

How can I get the SAR and DAR for this file?
 

andyk

Member
If you're still after this, you need to tell ffprobe what you want. I think what you're after is

Code:
ffprobe -v error -pretty -select_streams v -show_entries stream=display_aspect_ratio,sample_aspect_ratio,width,height,coded_width,coded_height <name of file>
 
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