[Cin] Set stream sample aspect ratio in ffmpeg.C

[Terje J. Hanssen]

Den 07.01.2024 13:07, skrev Andrew Randrianasulu:
>
>
> вс, 7 янв. 2024 г., 14:48 Terje J. Hanssen <terjejhanssen at gmail.com>:
>
>
>     Den 06.01.2024 20:42, skrev Phyllis Smith:
>>     Applied the 3 patches and still a problem playing DVD on LG
>>     device which previously worked.  Not to be difficult, but if we
>>     break DVD/Bluray disc creation, it will probably never work again
>>     and I use it frequently.
>>
>>     CinGG is never going to be perfect but it has been working this
>>     way for a long time and it has been usable, even if the DAR is
>>     not always right. There must be another way to reset that if
>>     needed.  But I will keep testing.
>>
>>         I think right now we have issues with ffmpeg internals
>>         (libavformat) not quite happy with stream (container) level
>>         SAR being set ... it breaks our custom dvd/bluray encoding,
>>         as discovered by Phyllis.
>>
>>         I am looking into this and audio bug but so far no solution
>>         for either,sorry.
>>
>>
>>
>
>     Yes, even that DVD and Blu-ray video discs are lesser usual than
>     previously, I agree we have to keep this features working in CinGG.
>     I guess it is the autoplay function that may not work, and that a
>     wrong aspect ratio video disc format possibly can be seen as data
>     discs(?)
>
>     Phyllis, have  you tried if possibly VLC's Media> Open Disc can
>     playback the DVD or BD video format?
>
>     As I said, also at the icon level in Gnome File manager, it it
>     possible to see that the CinGG rendered webm files are visually
>     squeezed horizontally, compared with the correct format muxed with
>     FFmpeg 6.0:
>     easy to see the difference between 4:3 sqeezed webm vs 16:9 wide
>     from (HDV) wide format.
>
>     In VLC these files are loaded squeezed as default, but it can be
>     easily corrected with VLC's Videol > Aspect Ratio and select 4:3
>     for webm from SD DV sources and 16:9 for webm from HDV 1080i files.
>
>
>     Not to repeat myself, but below is a condensed output from how
>     Mediainfo and FFprobe detect the aspect ratios of my tested SD and
>     HDV sources and webm files:
>
>     Source SD DV:
>     -------------
>     mediainfo dv01_07.dv | grep Display
>         Display aspect ratio                     : 4:3
>     ffprobe -hide_banner dv01_07.dv
>           Stream #0:0: Video: dvvideo, yuv420p, 720x576 [SAR 16:15 DAR
>     4:3], 25000 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
>
>     FFmpeg 6.0 webm:
>     mediainfo dv01_07_svt-av1_pr10.webm | grep Display
>         Display aspect ratio                     : 4:3
>     ffprobe -hide_banner dv01_07_svt-av1_pr10.webm
>       Stream #0:0: Video: av1 (Main), yuv420p(tv), 720x576 [SAR 1:1
>     DAR 5:4], SAR 16:15 DAR 4:3, 25 fps, 25 tbr, 1k tbn, 1k tbc
>
>
> yeah, DV tend to be non-square pixels (slightly). Not sure if we 
> account for this correctly or not on de/encoding.
>
>
>     Cin-aom-38_svt webm:
>     mediainfo dv01_07_av1_cingg.webm | grep Display
>         Display aspect ratio                     : 5:4
>     ffprobe -hide_banner dv01_07_av1_cingg.webm
>       Stream #0:0: Video: av1 (Main), yuv420p(tv,
>     bt470bg/unknown/unknown), 720x576 [SAR 1:1 DAR 5:4], 25 fps, 25
>     tbr, 1k tbn, 1k tbc
>
>
> not sure what happened here, may be you manually changed aspect ratio?
>

Repeated and controlled Cin-aom-38_svt webm rendering test of PAL SD-DV 
source:
-------------------------------------------------------------------------------
According to Cinelerra-GG Quick Start Guide, section 4 – Choose Output 
Format
You can skip this step if you want the format of your output to be the 
same as your input.

Loaded dv01_07.dv
Settings > Format | Preset: PAL 576i DV(D)
Settings > Preference > Appearance | YUV color space: BT601 PAL

The compositor image was seemingly correct ~DAR 4:3

Rendered 2832 frames in 27.481 secs: 103.053 fps !

mediainfo dv01_07_cingg_svt-av1+opus.webm | grep Display
Display aspect ratio                     : 5:4
ffprobe -hide_banner dv01_07_cingg_svt-av1+opus.webm
   Stream #0:0: Video: av1 (Main), yuv420p(pc, bt470bg/unknown/unknown), 
720x576, SAR 1:1 DAR 5:4, 25 fps, 25 tbr, 1k tbn

Loaded dv01_07_cingg_svt-av1+opus.webm in VLC, the default DAR was 
seemingly ~square (squeezed).
Changed it manually to 4:3 via menu.





>
>
>     Source HDV:
>     -----------
>     mediainfo hdv07_05.m2t | grep Display
>         Display aspect ratio                     : 16:9
>     ffprobe -hide_banner hdv07_05.m2t
>       Stream #0:0[0x810]: Video: mpeg2video (Main) ([2][0][0][0] /
>     0x0002), yuv420p(tv, bt709, top first), 1440x1080 [SAR 4:3 DAR
>     16:9], 25000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
>
>     FFmpeg webm:
>     mediainfo hdv07_05_m2t_svt-av1+opus.webm | grep Display
>         Display aspect ratio                     : 16:9
>     ffprobe -hide_banner hdv07_05_m2t_svt-av1+opus.webm
>       Stream #0:0: Video: av1 (Main), yuv420p(tv, bt709), 1440x1080
>     [SAR 1:1 DAR 4:3], SAR 4:3 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 1k tbc
>
>     Cin-aom-38_svt webm:
>     mediainfo hdv07_05_m2t_cingg_svt-av1+opus.webm | grep Display
>     Display aspect ratio                     : 4:3
>     ffprobe -hide_banner hdv07_05_m2t_cingg_svt-av1+opus.webm
>       Stream #0:0: Video: av1 (Main), yuv420p(pc,
>     bt709/unknown/unknown), 1440x1080 [SAR 1:1 DAR 4:3], 25 fps, 25
>     tbr, 1k tbn, 1k tbc
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