Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
On 6/26/2014 6:35 AM, BugMaster wrote: That is separate --psy (--no-psy) option in x264 and not --psy-rd Yeah, that was my point. :) - Derek ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel
Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
Ok, we dont have a separate psy option.yet On Jun 26, 2014 6:00 PM, Derek Buitenhuis derek.buitenh...@gmail.com wrote: On 6/26/2014 6:35 AM, BugMaster wrote: That is separate --psy (--no-psy) option in x264 and not --psy-rd Yeah, that was my point. :) - Derek ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel
Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
On 6/25/2014 1:22 AM, deep...@multicorewareinc.com wrote:
+/* In 444, chroma gets twice as much resolution, so halve quality when
psy-rd is enabled */
+if (p-internalCsp == X265_CSP_I444 p-psyRd)
+{
+p-cbQpOffset += 6;
+p-crQpOffset += 6;
+}
I dont really understand what the reasoning is for this? Is it just to make it
fit with the model psy-rd is currently using?
- Derek
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Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
This is primarily a visual quality improvement/psy-rd hack. In 444, since
chroma resolution is on par with luma, and our eyes arent very sensitive to
chroma, we increase the chroma QP so that those bits can be used up in
luma.
On Wed, Jun 25, 2014 at 4:35 PM, Derek Buitenhuis
derek.buitenh...@gmail.com wrote:
On 6/25/2014 1:22 AM, deep...@multicorewareinc.com wrote:
+/* In 444, chroma gets twice as much resolution, so halve quality
when psy-rd is enabled */
+if (p-internalCsp == X265_CSP_I444 p-psyRd)
+{
+p-cbQpOffset += 6;
+p-crQpOffset += 6;
+}
I dont really understand what the reasoning is for this? Is it just to
make it
fit with the model psy-rd is currently using?
- Derek
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___
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Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
In a sense, psy-rd encapsulates all those r-d algorithms/tweaks/hacks that improve visual quality but may hurt objective metrics like psnr/ssim. In 444, this qp hack is likely to hurt objective metrics, hence it's turned on only if psychovisual improvement is desired. On Jun 25, 2014 7:02 PM, Derek Buitenhuis derek.buitenh...@gmail.com wrote: On 6/25/2014 12:10 PM, Deepthi Nandakumar wrote: This is primarily a visual quality improvement/psy-rd hack. In 444, since chroma resolution is on par with luma, and our eyes arent very sensitive to chroma, we increase the chroma QP so that those bits can be used up in luma. Yah I get the idea of a chroma qp offset, I'm just wondering why it is specific to psy-rd? Cheers, - Derek ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel
Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
On 6/25/2014 3:45 PM, Deepthi Nandakumar wrote: In a sense, psy-rd encapsulates all those r-d algorithms/tweaks/hacks that improve visual quality but may hurt objective metrics like psnr/ssim. In 444, this qp hack is likely to hurt objective metrics, hence it's turned on only if psychovisual improvement is desired. OK. Was curious, since these are not lumped in with psy-rd in x264. - Derek ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel
Re: [x265] [PATCH 1 of 3] Chroma QP Offset: increase chroma QP when psy-rd is enabled
On Wed, 25 Jun 2014 23:18:48 +0530, Deepthi Nandakumar wrote: They are. encoder.c:x264_validate_parameters if( b_open i_csp = X264_CSP_I444 i_csp X264_CSP_BGR h-param.analyse.b_psy ) h-param.analyse.i_chroma_qp_offset += 6; On Wed, Jun 25, 2014 at 11:12 PM, Derek Buitenhuis derek.buitenh...@gmail.com wrote: On 6/25/2014 3:45 PM, Deepthi Nandakumar wrote: In a sense, psy-rd encapsulates all those r-d algorithms/tweaks/hacks that improve visual quality but may hurt objective metrics like psnr/ssim. In 444, this qp hack is likely to hurt objective metrics, hence it's turned on only if psychovisual improvement is desired. OK. Was curious, since these are not lumped in with psy-rd in x264. That is separate --psy (--no-psy) option in x264 and not --psy-rd ___ x265-devel mailing list x265-devel@videolan.org https://mailman.videolan.org/listinfo/x265-devel
