[FFmpeg-user] ffmpeg with x264 codec - Aspect ratio doesn't follow input

[Richard F]

Thanks for your reply,

The stream info for this file is as follows. As you can see the DAR
starts as 16:9, but the aspect changes several times during the
recording, x264 doesn't follow the changes, stays at 16:9.

If I force the SAR as you suggest the output is narrower than 4:3 and
still doesn't change with incoming aspect changes.

Input #0, mpegts, from '00001.ts':
  Duration: 00:59:49.47, start: 4529.649200, bitrate: 1477 kb/s
  Program 132
    Stream #0:0[0x18a1]: Video: mpeg2video (Main) ([2][0][0][0] /
0x0002), yuv420p(tv), 544x576 [SAR 32:17 DAR 16:9], max. 15000 kb/s, 25
fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x18a2](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000
Hz, stereo, s16p, 128 kb/s
    Stream #0:2[0x18a3](eng): Audio: mp3 ([3][0][0][0] / 0x0003), 0
channels, s16p
    Stream #0:3[0x18a6](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)

If I analyse the stream 5 minutes into the programme, like so:
ffmpeg -loglevel quiet -ss 00:05:00 -i "00001.ts" -t 10 -c copy 
-avoid_negative_ts 1 -f nut pipe:1 | ffmpeg -hide_banner -i pipe:0

Then the video stream is as follows:

Stream #0:0: Video: mpeg2video (Main) (mpg2 / 0x3267706D), yuv420p(tv),
544x576 [SAR 24:17 DAR 4:3], max. 15000 kb/s, SAR 32:17 DAR 16:9, 25
fps, 25 tbr, 90k tbn, 50 tbc

So it is meant to show as 4:3 here. 
I'm assuming the 2 sets of SAR/DAR are for container and stream which is
why it still shows as 16:9 after ffmpeg processing ?



On 25/05/2016 08:10, chronek wrote:
> Maybe your source not have sar 1:1... setdar will not change
> resolution, it will change only information about aspectratio and some
> players not read desired aspect ratio... Best try change to resolution
> what yuou want and setsar for it... ( -vf scale=x:y,setsar=1 )
>
> W dniu 2016-05-25 o 09:00, Richard F pisze:
>> Hi list,
>>
>> I have a number of MPEG2 TS DVB recordings that have aspect ratio
>> changes - e.g. older films or 4:3 programmes that have 16:9
>> continuity, trailers, adverts etc.
>>
>> I want to transcode to H264 using ffmpeg (3.02), but the output
>> aspect ratio does not follow the source when using the H264 codec.
>> But the aspect ratio does follow when using the xvid/mp4 codec.
>> I need x264 not mp4.
>> The problem is that (I think) the container DAR or SAR stays at 16:9
>> all the way through but the stream SAR or DAR doesn't follow the
>> source for whatever reason
>>
>> Is there a way to make x264 output follow the source aspect ratio at
>> the stream level ?
>>
>> Failing example :
>> ffmpeg -y -i 00001.ts -map 0:0 -map 0:1 -map 0:3 -c:v libx264 -preset
>> veryfast -profile:v high -level 4.0 -crf 20 -flags +loop -flags +ilme
>> -vf yadif=0:-1:0 -c:a:0 aac -b:a:0 128k -c:s copy -f mpegts file-1.ts
>> (same if I take out the profile and deinterlace settings)
>>
>> Working example (but large file and not so good quality, even if I
>> could use it):
>> ffmpeg -y -i 00001.ts -map 0:0 -map 0:1 -map 0:3 -c:v libxvid -q:v 3
>> -c:a:0 aac -b:a:0 128k -c:s copy -f mpegts file-1.ts
>>
>> If I add -vf setdar=dar=4/3, I can force the x264 version to be 4/3
>> but then all parts of the recording are always 4/3 which is also wrong.
>>
>> Behaviour is the same on VLC player, ffplay, and Kodi.
>>
>> Appreciate any pointers
>> Thanks
>> Richard
>>
>>
>>
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