x264 10bit-depth

[Anakunda]

hello,

today a 10 bit backend was presented. I wanted to ask if I can replace this backend with current x264, and furthermore if 10bit backend adds some quality to video, or will the video be bigger only without additional quality?
Mostly I encode from DVD and DVB(MPEG2).

[Lyris]

Those are both 8bit sources anyway.

[Blue_MiSfit]

Hi Anakunda,

10 bit is a tricky thing. Here are the main talking points currently, as I see them: (Take these with a grain of salt, as I'm not terribly knowledgable or experienced WRT 10 bit x264!)

1) 10 bit H.264 can only be decoded by payware decoders currently, like Mainconcept.
2) 10 bit encoding is best used with 10 bit sources, of which there are certainly none available to the average consumer
3) 10 bit gives better quality at the same bitrate AFAIK, due to greater precision
4) 10 bit is extremely slow currently, because ASM optimizations haven't been committed to the GIT yet. This WILL happen eventually

So, my advice would be to skip it for now. This will certainly change in the future!!

Derek

[Astrophizz]

I would think that 10 bit would also be good for 8 bit sources since it is lossy encoding and the increased precision would help.

[burfadel]

What does the 10-bit precision mean anyway? Is it possible to have the encoder chain 10-bit then have it downsample to 8-bit precision for the final encode?

[aegisofrime]

Originally Posted by Blue_MiSfit

Hi Anakunda,

10 bit is a tricky thing. Here are the main talking points currently, as I see them: (Take these with a grain of salt, as I'm not terribly knowledgable or experienced WRT 10 bit x264!)

1) 10 bit H.264 can only be decoded by payware decoders currently, like Mainconcept.
2) 10 bit encoding is best used with 10 bit sources, of which there are certainly none available to the average consumer
3) 10 bit gives better quality at the same bitrate AFAIK, due to greater precision
4) 10 bit is extremely slow currently, because ASM optimizations haven't been committed to the GIT yet. This WILL happen eventually

So, my advice would be to skip it for now. This will certainly change in the future!!

Derek

Thanks so much for summarizing it so clearly and succinctly It really clears up the confusion I had.

[Dark Shikari]

Originally Posted by Blue_MiSfit

2) 10 bit encoding is best used with 10 bit sources, of which there are certainly none available to the average consumer

It works just fine with 8-bit too. We will be adding things like gradfun into the filter chain to allow 8-bit stuff to be automatically upsampled to 10-bit anyways.

Of course, widespread adoption will depend on libavcodec getting 10-bit support.

[Selur]

We will be adding things like gradfun into the filter chain to allow 8-bit stuff to be automatically upsampled to 10-bit anyways.

Nice!

[J_Darnley]

Originally Posted by burfadel

What does the 10-bit precision mean anyway? Is it possible to have the encoder chain 10-bit then have it downsample to 8-bit precision for the final encode?

No.
5

[Amefurashi]

Originally Posted by Dark Shikari

Of course, widespread adoption will depend on libavcodec getting 10-bit support.

Is there the technical possibility (as far as you would know) to implement the 10-bit decoding in common standalone devices as well (eg. WDTV Live, Popcorn Hour etc.)?

[Dark Shikari]

Originally Posted by Amefurashi

Is there the technical possibility (as far as you would know) to implement the 10-bit decoding in common standalone devices as well (eg. WDTV Live, Popcorn Hour etc.)?

Sure, but it would probably require new hardware decoders.

[Amefurashi]

Originally Posted by Dark Shikari

Sure, but it would probably require new hardware decoders.

Ouch... I was hoping for a firmware-updating solution...

Thanks

[burfadel]

Originally Posted by J_Darnley

No.
5

I didn't think so

[lithoc]

Originally Posted by Dark Shikari

Sure, but it would probably require new hardware decoders.

How about UVD or Purevideo/VDPAU or intel?
May be we will have another round of ... "Who will be the 1st to support High10P"?

It's good to see some competition here.

[LoRd_MuldeR]

Originally Posted by lithoc

How about UVD or Purevideo/VDPAU or intel?

As the do not use GPU programs (shaders), which probably could be updated, but "hardwired" decoder chips integrated on the graphics board, which can not be updated, new hardware will be nedded

[Sharktooth]

..why not add gradfun (in addition to the standard deblock) into the decoder specs? it would save a lot of headaches...

[UltraTV]

What colorspace should be used for 10-bit encoding in x264? I have some 4:2:2 sources, but when I run them through they're being converted to yuv420.

x264_10 --pass 1 --preset veryslow --tune film --profile high10 --bitrate 30000 --stats ".stats" --keyint 96 --thread-input --sar 1:1 --output NUL "test.avs"avs 
[info]: 1920x1080p 1:1 @ 29970000/1250071 fps (cfr)
resize [warning]: converting from yuyv422 to yuv422p
resize [warning]: converting from yuv422p to yuv420p.........

[J_Darnley]

x264 only supports 4:2:0

[UltraTV]

I see, so 4:2:0 @ 10-bit. So sticking with yv12 is best.

[popper]

Originally Posted by Dark Shikari

Sure, but it would probably require new hardware decoders.

Originally Posted by lithoc

How about UVD or Purevideo/VDPAU or intel?
May be we will have another round of ... "Who will be the 1st to support High10P"?

It's good to see some competition here.

actually DS perhaps you might ask Francois about the SB Decoder ?, i think it will/might, as its not a fixed ASIC fixed-function decoding device such as NV and amd seem to use now, and he could probably work it into the patch if not already there somehow if it ever goes through.