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

[Terje J. Hanssen]

Den 20.05.2025 18:27, skrev Carl Zwanzig:
> On 5/19/2025 5:45 AM, Terje J. Hanssen wrote:
>> 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
>

First, a minor correction to the reference in my first post is:

"For video tapes, we always recommend capturing lossless, 10-bit, 4:2:2 
or better"
https://www.archivalworks.com/blog/best-practices-for-digitizing-and-preserving-analog-media

> If you're trying make high-quality copies of analogue video, you 
> really need to treat the analogue signal before digitizing it - at a 
> minimum there ought to be a time-base correcter (TBC) in there; 

Thanks for your feedback.
And yes, I agree. I didn't tell that I actually have a legacy pretty 
good TBC (built in a Videonics MX-1 videomixer) which I also used before 
A/D converting and capturing DV25 on a Datavideo DN-300 DV & HDV HDD 
recorder.  The MX-1 PAL version, which also had a usable noise filters, 
was specified as "broadcast quality" with 17,72 MHz sampling, 8-bit 
4:2:2 (not 10-bit as its successor MXPro).

So, I plan to apply the MX-1/TBC between the S-video player and the A/D 
converter the HDMI based chain above.

My suspection is that the visual lesser color and brightness from DV25 
playback, mainly is due to the format's limited 8-bit 4:2:0 sampling.


> better would be a waveform monitor and proc amp* so you can adjust 
> things.
>
> *for instance, if the white digitizes to 180 instead of 235 (or 
> 254/5), stretching that in ffmpeg loses intensity resolution as it has 
> to interpolate values.

This is beyond my knowledge.
What I also had available, but possibly is non-working now, is a legacy 
video-color corrector (Video Tech Designs VCC 3010).

(And not to mention, I also have a legacy Blackmagic A/D-SDI converter + 
Hyperdeck Shuttle2 SSD recorder, which managed 10-bit ProRes HQ 422 for 
both S-video and HDV.
But last time I tried, these devices were unhappily non-usable due to 
EOS BM firmware)


So therefore I am still curious in suggestions regarding the requested 
"10-bit Chroma upsampling" using ffmpeg and possible color noise 
filters(?) to benefit Analog (and also HDV) backup via HDMI?


Terje J. H



>
>
> OTOH, if you're only after "it looks pretty good", then disregard the 
> above :D.
>
> Later,
>
> z!
> who still remembers some of The Old Ways :D
>
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