lossless 4.2.0 video to lossless 4.2.2 - any issues?

[spicediver10191]

I've been asked to provide video in a lossless format different from my lossless master.

It's a 1080p UT Video .avi file being converted to a ProRes 422 .mov file.

My question: will there be any adverse effects on quality, particularly because of the up-conversion of 4.2.0 chroma subsampling to 4.2.2?

My video source details:
Format: YUV
Codec ID: ULH0
Codec ID/Info: Ut Video Lossless Codec
Codec ID/Hint: Ut Video
Bit rate: 186 Mb/s
Width: 1 920 pixels
Height: 1 080 pixels
Display aspect ratio: 16:9
Frame rate: 23.976 (24000/1001) FPS
Color space: YUV
Chroma subsampling: 4:2:0
Compression mode: Lossless
Bits/(Pixel*Frame): 3.736

A test conversion in Adobe Media Encoder, using the ProRes 422 profile, produces a .mov file of similar size with these specs:

Format: ProRes
Format profile: 422 HQ default
Codec ID: apch
Bit rate mode: Variable
Bit rate : 174 Mb/s
Width: 1 920 pixels
Height: 1 080 pixels
Display aspect ratio: 16:9
Frame rate mode: Constant
Frame rate: 23.976 (24000/1001) FPS
Color space: YUV
Chroma subsampling: 4:2:2
Scan type: Progressive
Bits/(Pixel*Frame): 3.508
Writing library: adb0
Color primaries: BT.709
Transfer characteristics: BT.709
Matrix coefficients: BT.709

[poisondeathray]

Progressive chroma upsampling 420 => 422 is usually handled ok in Adobe; however there were some older versions and point releases that interpreted UT in AVI as "interlaced" by default, and you had to manually interpret the file as "progressive" . If it's misinterpreted, it gets deinterlaced, and you incur degredation. It looks like softening, blurring and some aliasing and should be easy to see.

Your title says "lossless 4.2.0 video to lossless 4.2.2 - any issues?" , but Prores is a lossy codec. It should say "lossless to lossy"

But YUV UT video variants are actually lossy in all Adode versions. They get converted to RGB instead of being treated as YUV. The main significance affecting people is overbrights Y>235 and subblacks Y<16 are clipped. Depending on what the source was, this can have significant impact

If you "need" UT 4:2:0 to Prores, I would avoid Adobe, unless you know your source is 100% of useful data is within Y16-235. If it's not the case, I would use ffmpeg , or vdub2 can do the prores conversion properly handling UT video as YUV

[spicediver10191]

Thanks PDR, very helpful. I thought some versions of ProRes were lossless for some reason.

I'm comfortable with Vdub2, so I'll use that.

Any changes to the default encoding settings you would recommend? (see screenshot)

[Attachment 71548 - Click to enlarge]

[poisondeathray]

Looks ok, but are you sure prores is what you want ? You should be asking which "lossless format" they want and give them that, because prores is lossy (minimally lossy, but still lossy)

I've been asked to provide video in a lossless format different from my lossless master.

Is there any other background info ? Did they say why ?

[spicediver10191]

Looks ok, but are you sure prores is what you want ? You should be asking which "lossless format" they want and give them that, because prores is lossy (minimally lossy, but still lossy)

I've been asked to provide video in a lossless format different from my lossless master.

Is there any other background info ? Did they say why ?

Yeah, it's kinda garbled. They said 'Quicktime' and so I assumed ProRes...

[poisondeathray]

Usually anyone that wants "quicktime" is Mac based

My guess is Prores HQ is probably "good enough"...but I would double check with them

The next grade up is Prores 4444XQ, near lossless (but still not lossless)

[spicediver10191]

Usually anyone that wants "quicktime" is Mac based

My guess is Prores HQ is probably "good enough"...but I would double check with them

The next grade up is Prores 4444XQ, near lossless (but still not lossless)

Thanks, I'll try again and see if I can get more detail.

The file is to be authored for a Bluray disc, so I can't imagine why anything than a lossless source would be used

[poisondeathray]

The file is to be authored for a Bluray disc, so I can't imagine why anything than a lossless source would be used

Many commercial BD's are actually produced from a Prores intermediate

There is not going to be much difference in the BD end result between using Prores HQ vs. lossless/uncompressed , unless you look at single frames, zoomed in

There aren't any 8bit 4:2:0 lossless codecs with wide compatibility for quicktime. If you wanted lossless , I would go uncompressesd 10bit 422, or "v210" in mov . This is highly compatible on all professional video platforms/software, but large filesizes . Then you might get complaints about the filesize. Hence the compromise with Prores HQ, or 444XQ

[spicediver10191]

[QUOTE=poisondeathray;2692835]

There aren't any 8bit 4:2:0 lossless codecs with wide compatibility for quicktime. If you wanted lossless , I would go uncompressesd 10bit 422, or "v210" in mov . This is highly compatible on all professional video platforms/software, but large filesizes . Then you might get complaints about the filesize. Hence the compromise with Prores HQ, or 444XQ

File size is not an issue, so that sounds like a pretty foolproof solution.

Are the .mov encoding options you mention in this list of Vdub2 profiles? (see screenshot)


[Attachment 71549 - Click to enlarge]

[poisondeathray]

video=>compression=>uncompressed (it's the one above ProRes in your screenshot)

Select Pixel Format Button, 4:2:2 YCbCr 10bit (v210), Push OK

-----

For ProRes 4444 XQ, it's in the drop down menu in your 1st screenshot (instead of "high quality")

[spicediver10191]

video=>compression=>uncompressed (it's the one above ProRes in your screenshot)

For ProRes 4444 XQ, it's in the drop down menu in your 1st screenshot (instead of "high quality")

Thanks.

For the 4444XQ profile choice - I'll encode this option too, as a test - do you manually change the YUV 4:2:2 dropdown above it to 4:4:4?


[Attachment 71554 - Click to enlarge]

[poisondeathray]

For the 4444XQ profile choice - I'll encode this option too, as a test - do you manually change the YUV 4:2:2 dropdown above it to 4:4:4?

I would assume yes; I haven't used it in vdub2

[Sharc]

Sorry for my dumb question: Blu-Ray is 4:2:0 only AFAIK. So why would one want to upsample 4:2:0 footage to 4:2:2 or 4:4:4 at all? Any benefit or is it just a limitation of the tools/platform used?

[spicediver10191]

Sorry for my dumb question: Blu-Ray is 4:2:0 only AFAIK. So why would one want to upsample 4:2:0 footage to 4:2:2 or 4:4:4 at all? Any benefit or is it just a limitation of the tools/platform used?

I think in production environments such a choice may have its benefits - but I'll leave poisondeathray to answer that one.

Encode tests with the 4444XQ ProRes profile actually gave me smaller files/lower bitrate, so have dumped that option.

Instead I'm just creating an uncompressed .mov file, plus a ProRes 422 HQ .mov file because that profile encodes at a similar bitrate to my lossless source. The 4:2:2 subsampling is the minimum for this profile I believe, so I'm just leaving it alone.

[poisondeathray]

Yes, "normal" BD is 8-bit

It's a limitation of Prores (even LT and Proxy are 422) . All professional tools tend to be 4:2:2 minimum (probably because of interlace legacy. 4:2:0 interlace has many issues) .
It's the same as DVD authoring using Pro/Studio tools - they usually want 4:2:2 input, but DVD is 8bit 4:2:0

If the production chain they used supported UT 4:2:0 properly, that would actually be better . Up/Down sampling is not a lossless transform by they tools they use (You would need to use nearest neighbor) , so the chroma quality is actually going to be slightly lower.

[poisondeathray]

Encode tests with the 4444XQ ProRes profile actually gave me smaller files/lower bitrate, so have dumped that option.

Maybe something up with vdub2 implementation; A quick test in ffmpeg shows 1.6-1.7x more bitrate for 444xq vs. hq

[Sharc]

Yes, "normal" BD is 8-bit

It's a limitation of Prores (even LT and Proxy are 422) . All professional tools tend to be 4:2:2 minimum (probably because of interlace legacy. 4:2:0 interlace has many issues) .
It's the same as DVD authoring using Pro/Studio tools - they usually want 4:2:2 input, but DVD is 8bit 4:2:0

If the production chain they used supported UT 4:2:0 properly, that would actually be better . Up/Down sampling is not a lossless transform by they tools they use (You would need to use nearest neighbor) , so the chroma quality is actually going to be slightly lower.

Thanks. All clear now.

[poisondeathray]

Encode tests with the 4444XQ ProRes profile actually gave me smaller files/lower bitrate, so have dumped that option.

Maybe something up with vdub2 implementation; A quick test in ffmpeg shows 1.6-1.7x more bitrate for 444xq vs. hq

In vdub2 using the same input, the file sizes were about 1/2 of what ffmpeg produced . Even on the q2 setting (highest quality), the bitrates were signifcantly lower. There are different libavcodec prores encoders, it might using a different one

Also beware vdub tags them as BT.470 ; this might cause problems

Matrix coefficients : BT.470 System B/G

You can write prores metadata using ffmpeg bitstream filter or AMCDXVideoPatcher
https://ffmpeg.org/ffmpeg-bitstream-filters.html#prores_005fmetadata
https://mogurenko.com/2021/01/29/amcdx-video-patcher-v0-6-7/

[spicediver10191]

Encode tests with the 4444XQ ProRes profile actually gave me smaller files/lower bitrate, so have dumped that option.

Maybe something up with vdub2 implementation; A quick test in ffmpeg shows 1.6-1.7x more bitrate for 444xq vs. hq

Which front end you using for FFmpeg?

[spicediver10191]

Yes, "normal" BD is 8-bit

It's a limitation of Prores (even LT and Proxy are 422) . All professional tools tend to be 4:2:2 minimum (probably because of interlace legacy. 4:2:0 interlace has many issues) .
It's the same as DVD authoring using Pro/Studio tools - they usually want 4:2:2 input, but DVD is 8bit 4:2:0

If the production chain they used supported UT 4:2:0 properly, that would actually be better . Up/Down sampling is not a lossless transform by they tools they use (You would need to use nearest neighbor) , so the chroma quality is actually going to be slightly lower.

If you were to create an uncompressed version in 4.2.0 from a UT master, what settings would you use?

[poisondeathray]

Which front end you using for FFmpeg?

No front end, just ffmpeg directly

If you were to create an uncompressed version in 4.2.0 from a UT master, what settings would you use?

v210 as described earlier. That is the standard universal currency for uncompressed video in professional NLE and video equipment / studio environments HD-SDI for >20 years

Pro video is always 10bit as well . So 10bit422 is the standard (even though delivery on BD is 8bit420)



8bit 422 gets a bit wonky, because on windows NLE's it's UYVY that is universally preferred, but on mac environments 2vuy is preferred . Both are 8bit 422 uncompressed, they are just organized differently. If you use the wrong version, it gets clipped / mistreated as RGB . This is the main reason why "lossless" codecs like huffyu, ut video etc.. are not lossless in NLE's. 422 versions tend to decompress to YUY2 (also 8bit 422, but the wrong arrangement)

[spicediver10191]

..

Thanks again pdr - this is all very helpful.