[FFmpeg-user] ffmpeg with x264 codec - Aspect ratio doesn't follow input
chronek at interia.eu
Wed May 25 14:49:17 CEST 2016
Forcing alone sar or dar it will not change resolution, only it will
change information for player how it schould scale to output. sar is
pixel size, dar aspect ratio.. So when you had 544x576 [SAR 32:17 DAR
16:9] it means you have source 544x576 what is real aspect ratio 17:18
of resolution, but with sar (pixel size) and dar (output aspect ratio)
it should say to player to rescale, but not every player doint it right,
so solution is rescale to get real aspect ratio of 16:9 , so in your
file use -vf scale=1024:576,setsar=1:1 (or setdar=16:9) it will rescale
source resolution to resolution where pixel is 1x1 and will set sar/dar
information in file (because normal rescaling would try keep information
about pixel size)
W dniu 2016-05-25 o 11:18, Richard F pisze:
> 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) ( /
> 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 ( / 0x0003), 48000
> Hz, stereo, s16p, 128 kb/s
> Stream #0:2[0x18a3](eng): Audio: mp3 ( / 0x0003), 0
> channels, s16p
> Stream #0:3[0x18a6](eng): Subtitle: dvb_subtitle ( / 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
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