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I've created a bunch of variants and a DASH manifest for Sintel, which more or less works, but does not pass validation. The issue is when I want to scale a video to a specific width, but the height that maintains the aspect ratio is not a whole number - or vice versa. For example, I've tried 640:-1, 640: -2, and 640:290 as the value of "-vf scale=", but either ffmpeg rejects it, or validation fails. How can I transcode to these resolutions?

Error log from conformance site:

### error: moov-1:trak-1:tkhd-1 
### Width in TrackHeaderBox is not matching with out of box width information 
WARNING: Sample description width 2560 not the same as track width 2558.532104
Warning: Unknown atom found "pasp": video sample descriptions would not normally contain this
WARNING: unknown mvex atom 'trep'
WARNING: unknown/unexpected atom 'meta'

My ffmpeg and MP4Box commands (OSX):

OUTDIR="sintel-transcoded"
#VIDOPTS24="-an -c:v libx264 -r 24 -tune animation -force_key_frames expr:gte(t,n_forced*3)"
VIDOPTS24="-an -c:v libx264 -tune animation -x264opts keyint=72:min-keyint=72:no-scenecut -vsync passthrough"

mkdir -p $OUTDIR

ffmpeg -i $SOURCEDIR/sintel_4k.mov \
$VIDOPTS24 -vf scale=320:146 -profile:v baseline -level 3.0 -crf 31 -maxrate 170k -bufsize 170k $OUTDIR/sintel_320.mp4 \
$VIDOPTS24 -vf scale=480:-2 -profile:v baseline -level 3.0 -crf 30 -maxrate 330k -bufsize 330k $OUTDIR/sintel_480.mp4 \
$VIDOPTS24 -vf scale=640:290 -profile:v baseline -level 3.1 -crf 30 -maxrate 500k -bufsize 500k $OUTDIR/sintel_640.mp4 \
$VIDOPTS24 -vf scale=640:290 -profile:v baseline -level 3.1 -crf 25 -maxrate 1000k -bufsize 1000k $OUTDIR/sintel_640_hq.mp4 \
$VIDOPTS24 -vf scale=960:-2 -profile:v main -level 3.1 -crf 19 -maxrate 2800k -bufsize 2800k $OUTDIR/sintel_960.mp4 \
$VIDOPTS24 -vf scale=1280:582 -profile:v main -level 3.1 -crf 19 -maxrate 4000k -bufsize 4000k $OUTDIR/sintel_1280.mp4 \
$VIDOPTS24 -vf scale=1920:-2 -profile:v high -level 4.0 -crf 20 -maxrate 6800k -bufsize 6800k $OUTDIR/sintel_1920.mp4 \
$VIDOPTS24 -vf scale=2560:1162 -profile:v high -level 5.0 -crf 19 -maxrate 12000k -bufsize 12000k $OUTDIR/sintel_2560.mp4 \
$VIDOPTS24 -profile:v high -level 5.1 -crf 20 -maxrate 20000k -bufsize 20000k $OUTDIR/sintel_3840.mp4 \
-vn -c:a aac -b:a 64k $OUTDIR/sintel_audio_64k.mp4 \
-vn -c:a aac -b:a 96k $OUTDIR/sintel_audio_96k.mp4 \
-vn -c:a aac -b:a 128k $OUTDIR/sintel_audio_128k.mp4

cd $OUTDIR

MP4Box -dash-strict 3000 -rap -frag-rap -profile dashavc264:live -bs-switching no -out Manifest.mpd \
sintel_3840.mp4:bandwidth=20000000 \
sintel_2560.mp4:bandwidth=12000000 \
sintel_1920.mp4:bandwidth=6800000 \
sintel_1280.mp4:bandwidth=4000000 \
sintel_960.mp4:bandwidth=2800000 \
sintel_640_hq.mp4:bandwidth=1000000 \
sintel_640.mp4:bandwidth=500000 \
sintel_480.mp4:bandwidth=330000 \
sintel_320.mp4:bandwidth=170000 \
sintel_audio_128k.mp4 \
sintel_audio_96k.mp4 \
sintel_audio_64k.mp4

mkdir dist
mv *dash* Manifest.mpd dist
  • Using "-vf scale=1920:-1" (auto 'y') or "-vf scale=1920:-8" (evenly divisible by 8) ought to work. Are you using the newest ffmpeg? -- There are online Stream Validators like: viblast.com/stream-validator . Try a different resizer within ffmpeg. – Rob Jan 27 '18 at 20:09
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The scale filter resets the sample aspect ratio to match the original display aspect ratio. You should add setsar=1 after each scale. In any case, videos don't contain pixel count with fractional components, and FFmpeg won't output those.

I'm not sure about DASH but I suppose the validator expects each variant to have the same exact aspect ratio. In your command list, I can see 640x290 and 1280x582, which are not the same aspect. If DASH needs all to be same, the latter should be 1280x580

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