[FFmpeg-user] Video stretched wide

[Steve Zemlicka]

It seems the issue must stem from the source having two SAR/DAR values as
follows:
Stream #0:0: Video: mpeg2video (Main), yuv420p(tv, smpte170m, progressive),
720x480 [SAR 8:9 DAR 4:3], SAR 1:1 DAR 3:2, 29.97 fps, 29.97 tbr, 1k tbn
(default)

Adding "-aspect 4:3" to the ffmpeg command was sufficient to output a
result consistent with the source.

On Fri, Feb 24, 2023 at 8:47 AM Steve Zemlicka <stevezemlicka at gmail.com>
wrote:

> I am transcoding some videos from a mpeg2 MKV extracted from a DVD using
> makemkv to x264/x265.  I noticed the transcoded videos seemed stretched
> wide (using multiple players) as compared to the original MKV.  It's very
> slight but especially noticeable when looking at the black bars.  Though I
> first noticed this with the hevc_nvenc encoder, I've also verified it is
> consistent even with the libx264 with the following minimal command:
> ffmpeg -i input_test.mkv -c:v libx264 -crf 0 -c:a copy output_test.mp4
>
> Mediainfo indicates the resolution and aspect ratio are identical between
> the two.  Both are 720x480 (3:2).  Normally I'd look at the player being
> the culprit but I did a test this morning using Handbrake and the output
> from this does not have the issue.  I suspect I'm doing something wrong but
> I can't seem to figure it out.  I tried looking this up but most results
> seemed to stem from resizing, cropping, etc. and I'm not doing any of that
> (at least not intentionally).  Not sure if attachments will come through
> but I'm attaching screenshots to this message.  Any thoughts or suggestions?
>
> I am on ffmpeg version n5.1.2
>
> The terminal output is as follows:
> [szemlicka at xps finals]$ ffmpeg -i input_test.mkv -c:v libx264 -crf 0 -c:a
> copy output_test.mp4
> ffmpeg version n5.1.2 Copyright (c) 2000-2022 the FFmpeg developers
>   built with gcc 12.2.0 (GCC)
>   configuration: --prefix=/usr --disable-debug --disable-static
> --disable-stripping --enable-amf --enable-avisynth --enable-cuda-llvm
> --enable-lto --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl
> --enable-ladspa --enable-libaom --enable-libass --enable-libbluray
> --enable-libbs2b --enable-libdav1d --enable-libdrm --enable-libfreetype
> --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack
> --enable-libmfx --enable-libmodplug --enable-libmp3lame
> --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg
> --enable-libopus --enable-libpulse --enable-librav1e --enable-librsvg
> --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh
> --enable-libsvtav1 --enable-libtheora --enable-libv4l2 --enable-libvidstab
> --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp
> --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2
> --enable-libxvid --enable-libzimg --enable-nvdec --enable-nvenc
> --enable-opencl --enable-opengl --enable-shared --enable-version3
> --enable-vulkan
>   libavutil      57. 28.100 / 57. 28.100
>   libavcodec     59. 37.100 / 59. 37.100
>   libavformat    59. 27.100 / 59. 27.100
>   libavdevice    59.  7.100 / 59.  7.100
>   libavfilter     8. 44.100 /  8. 44.100
>   libswscale      6.  7.100 /  6.  7.100
>   libswresample   4.  7.100 /  4.  7.100
>   libpostproc    56.  6.100 / 56.  6.100
> Input #0, matroska,webm, from 'input_test.mkv':
>   Metadata:
>     ENCODER         : Lavf58.76.100
>   Duration: 00:01:29.04, start: 0.051000, bitrate: 5965 kb/s
>   Stream #0:0: Video: mpeg2video (Main), yuv420p(tv, smpte170m,
> progressive), 720x480 [SAR 8:9 DAR 4:3], SAR 1:1 DAR 3:2, 29.97 fps, 29.97
> tbr, 1k tbn (default)
>     Metadata:
>       DURATION        : 00:01:28.939000000
>     Side data:
>       cpb: bitrate max/min/avg: 9800000/0/0 buffer size: 1835008
> vbv_delay: N/A
>   Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s
> (default)
>     Metadata:
>       DURATION        : 00:01:29.043000000
>   Stream #0:2(eng): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
>     Metadata:
>       DURATION        : 00:01:29.043000000
> Stream mapping:
>   Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))
>   Stream #0:1 -> #0:1 (copy)
> Press [q] to stop, [?] for help
> [libx264 @ 0x55a167189c80] using SAR=1/1
> [libx264 @ 0x55a167189c80] using cpu capabilities: MMX2 SSE2Fast SSSE3
> SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
> [libx264 @ 0x55a167189c80] profile High 4:4:4 Predictive, level 3.0,
> 4:2:0, 8-bit
> [libx264 @ 0x55a167189c80] 264 - core 164 r3095 baee400 - H.264/MPEG-4 AVC
> codec - Copyleft 2003-2022 - http://www.videolan.org/x264.html - options:
> cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=0
> mixed_ref=1 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11
> fast_pskip=0 chroma_qp_offset=0 threads=15 lookahead_threads=2
> sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0
> constrained_intra=0 bframes=0 weightp=2 keyint=250 keyint_min=25
> scenecut=40 intra_refresh=0 rc=cqp mbtree=0 qp=0
> [mp4 @ 0x55a16718ff00] track 1: codec frame size is not set
> Output #0, mp4, to 'output_test.mp4':
>   Metadata:
>     encoder         : Lavf59.27.100
>   Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p(tv, smpte170m,
> progressive), 720x480 [SAR 1:1 DAR 3:2], q=2-31, 29.97 fps, 29969 tbn
> (default)
>     Metadata:
>       DURATION        : 00:01:28.939000000
>       encoder         : Lavc59.37.100 libx264
>     Side data:
>       cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
>   Stream #0:1(eng): Audio: ac3 (ac-3 / 0x332D6361), 48000 Hz, 5.1(side),
> fltp, 448 kb/s (default)
>     Metadata:
>       DURATION        : 00:01:29.043000000
> frame= 2664 fps=116 q=-1.0 Lsize=  261131kB time=00:01:28.99
> bitrate=24037.9kbits/s dup=525 drop=0 speed=3.87x
> video:256229kB audio:4867kB subtitle:0kB other streams:0kB global
> headers:0kB muxing overhead: 0.013529%
> [libx264 @ 0x55a167189c80] frame I:39    Avg QP: 0.00  size:164396
> [libx264 @ 0x55a167189c80] frame P:2625  Avg QP: 0.00  size: 97511
> [libx264 @ 0x55a167189c80] mb I  I16..4: 18.4% 20.8% 60.7%
> [libx264 @ 0x55a167189c80] mb P  I16..4:  2.6% 16.3%  6.3%  P16..4: 31.5%
> 11.0%  8.8%  0.0%  0.0%    skip:23.5%
> [libx264 @ 0x55a167189c80] 8x8 transform intra:62.3% inter:79.9%
> [libx264 @ 0x55a167189c80] coded y,uvDC,uvAC intra: 99.2% 97.0% 97.0%
> inter: 59.7% 55.0% 55.0%
> [libx264 @ 0x55a167189c80] i16 v,h,dc,p: 46% 35% 18%  1%
> [libx264 @ 0x55a167189c80] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 43% 38% 11%  1%
>  1%  1%  1%  1%  2%
> [libx264 @ 0x55a167189c80] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 37% 30% 13%  3%
>  5%  3%  3%  3%  3%
> [libx264 @ 0x55a167189c80] i8c dc,h,v,p: 17% 36% 44%  3%
> [libx264 @ 0x55a167189c80] Weighted P-Frames: Y:5.7% UV:3.6%
> [libx264 @ 0x55a167189c80] ref P L0: 62.0%  9.2% 18.1% 10.3%  0.3%
> [libx264 @ 0x55a167189c80] kb/s:23613.21
>