[FFmpeg-user] Benefits from Chroma Upsampling v4l2 8bit 422 to 10bit 422 FFV1 backup?

[Terje J. Hanssen]

Den 22.05.2025 05:37, skrev Andrew Randrianasulu:
> you
>
> пн, 19 мая 2025 г., 15:55 Terje J. Hanssen <terjejhanssen at gmail.com>:
>
>     My first backup generation of my PAL Analog S-video footages on tapes
>     was digitized to SD 576i50 DV25 with 8-bit 4:2:0 color depth and
>     25 Mb/s
>     video bit rate.
>     IMO playback from DV25 backup files visually lack some brightness and
>     colors compared with native playback from S-video tapes.
>
>     Now I am testing another backup method with purpose of best practical
>     video quality using ffmpeg to encode lossless compressed FFV1.mkv
>     files:
>
>          Analog video camera/player --> S-video/HDMI converter -->
>     HDMI/USB3
>     capture card --> v4l2 --> ffmpeg/ FFV1.mkv
>
>     10-Bit 4:2:2 Video is recommended for Analog Tape Transfer due to
>     color
>     shades and branding
>     https://www.archivalworks.com/blog/10-bit-video-transfer
>
>
>     Well, my ms2130 HDMI/USB3 video capture card
>
>
>
> while looking around for "something else" I noted this thread talks 
> about patching firmware on ms2130 device to disable sharpening and get 
> unclipped (full range) YUV values.
>
> Not that it should matter for cassette video source, but for VGA 
> capture it apparently mattered:
>
> https://68kmla.org/bb/index.php?threads/decent-video-capture-for-30.49954/
>
> If anyone want to test this route do not forgot to back up original 
> firmware first!


Thank you for the tip, which I have noticed for a possible attempt, 
later on.

I looked at the two (TV) test pictures, before and after fw patching, 
but I couldn't discover any visual differences(?)
https://github.com/steve-m/ms2130_patcher?tab=readme-ov-file#macrosiliconultrasemi-ms2130-firmware-patcher

"patching firmware on ms2130 device to disable sharpening and get 
unclipped (full range) YUV values."
Not sure what this really mean, but I expect this will still be 8-bit 
color depth(?)
IMO it is safest to follow the idiom "if it ain't broke, don't fix it".
https://www.cnx-software.com/2022/11/07/ms2130-based-4k-hdmi-to-usb-3-0-video-capture-dongle-sells-for-19/


ffmpeg -hide_banner -f v4l2 (from case 1)
Input
     Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422,
Output
     Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p(tv, progressive)

That is, I will keep 8-bit 422 through the whole workflow, via first TBC 
rectification (MX-1).
The A/D converter is probably specified using maximum 10-bit 1.62 MSPS 
sampling.


My purpose and device environment as a reference, was mostly discussed 
in a topic back in 2023:
[FFmpeg-user] Capture HDV and S-Video from tape via HDMI-USB to 422 FFV1
https://www.mail-archive.com/ffmpeg-user@ffmpeg.org/msg33225.html


The real new topic meant this time, was my curiosity when I discovered 
this post on reddit
Upsampling by Denoising 8-bit footage into 10-bit? : r/colorists
https://www.reddit.com/r/colorists/comments/fo5oez/denoising_8bit_footage_into_10bit/


Terje J. H


>
>
>
>     achieves YUYV2 or 8-bit
>     4:2:2, which is not 10-bit but yet twice as much color info compared
>     with DV25 4:2:0.
>
>
>     Q1
>     Therefore my question here if it yet may be
>          Benefits from Chroma "Upsampling" v4l2 8bit 422 to 10bit 422
>     FFV1
>     backup?
>
>     While some say this is fake upsampling like filling 8-bit data in a
>     10-bit container, other say this may be beneficial with temporal
>     noise
>     filtering
>     https://www.eoshd.com/comments/topic/26710-8bit-%E2%86%92-10bit-video-with-temporal-noise-filtering-stunning-results/
>
>     Q2
>     So let me hear if this may be applied with some ffmpeg denoising
>     filters
>     like time base correcting, tape grain or snow?
>