constant quantizer for vp9

[rockerovo]

hey

how I can use constant quantizer mode on vp9
I know there is Constant Quantizer (Q) and you can select it by using --end-usage=q and -min-q=10 --max-q=10

so my question is this mode like the mode on x264 and the x265 range is from 0 to 51?

but when i trying to encode file with q = 10 on x264 or x265 i got bitrate range is from 150 mb/s to 200 mb/s but when I'm using vp9 with --end-usage=q and -min-q=10 --max-q=10 i got file with 23 mb/s how can this is possible ?


Codec: WebM Project VP9 Encoder v1.7.0

[gdx]

Although it appears that you had missed "--cq-level=10" in the command line, the explanations of the bitrate is other, the cq mode is basically the same but the scale is different as in vp9 range goes 0 to 63 also the weight of each values is different making it not a 1=1 correspondence. The bitrate for the q values of both vp9 and x265 met at some point, this point depends of the video ( from experience I think that is around q19±3), from this point lower q values for vp9 make that the obtained bitrate lower for vp9 than x265, and higher q values gives higher bitrate for vp9 than x265.

Also if you put the full encoding line can help find some errors in it, this is important as you can have put a constraint without noticing it.

[rockerovo]

my command for x264 :

with qp mode :

x264 qp = 10

x264 --frames 100 --profile high --preset medium -o x264_10.264 --input-csp i420 --output-csp i420 --input-depth 8 --output-depth 8 --input-res 1920x1080 --fps 50 --verbose --dump-yuv x264_10.yuv /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --qp=10

the output bitrate = 165813.47 kb/s

x265 qp = 10

x265 -o hevc_3500.265 --output-depth 8 --input ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --fps 50 --input-res 1920x1080 --input-depth 8 --input-csp 1 -P main -p medium --qp=10 --frames=100 --recon x265_40.yuv --recon-depth 8 --recon x265_50.yuv

the bitrate = 132423.19 kb/s

with crf mode :

x264 crf=20

x264 --frames 100 --profile high --preset medium -o x264_10.264 --input-csp i420 --output-csp i420 --input-depth 8 --output-depth 8 --input-res 1920x1080 --fps 50 --verbose --dump-yuv x264_10.yuv /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --crf=20

bitrate = 8865.74 kb/s


x265 : crf = 20

x265 -o hevc_3500.265 --output-depth 8 --input ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --fps 50 --input-res 1920x1080 --input-depth 8 --input-csp 1 -P main -p medium --crf=20 --frames=100 --recon x265_40.yuv --recon-depth 8 --recon x265_50.yuv
yuv [info]: 1920x1080 fp

bitrate = 6388.08 kb/s

--------------------------------------------------------------------------

for vp9

vp9 q mode = 10

./vpxenc --output=ReadySteadyGo_1920x1080_120fps_420_8bitzzz. webm --codec=vp9 --passes=2 --good -v --i420 --width=1920 --height=1080 --profile=0 --fps=50000/1001 --auto-alt-ref=1 --input-bit-depth=8 --tile-columns=4 /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --bit-depth=8 --end-usage=q --limit=100 --min-q=30 --max-q=30 --threads=4 --cpu-used=4 Warning: Bad quantizer values. Quantizer values should not be equal, and should differ by at least 8.
1 encoder configuration warning(s). Continue? (y to continue) y

bitrate: 24089 kb/s





cq mode = 20

./vpxenc --output=RrreadySteadyGo_1920x1080_120fps_420_8bit_. webm --codec=vp9 --passes=2 --good -v --i420 --width=1920 --height=1080 --profile=0 --fps=50000/1001 --input-bit-depth=8 /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --bit-depth=8 --end-usage=q --limit=100 --cq-level=20 --tile-columns=4 --threads=4 --cpu-used=4

bitrate = 15090 kb/s


when change end-usage to cq :

./vpxenc --output=RrreadySteadyGo_1920x1080_120fps_420_8bit_. webm --codec=vp9 --passes=2 --good -v --i420 --width=1920 --height=1080 --profile=0 --fps=50000/1001 --input-bit-depth=8 /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --bit-depth=8 --end-usage=cq --limit=100 --cq-level=20 --tile-columns=4 --threads=4 --cpu-used=4

bitrate = 8865.74 kb/s

and if i set cq=24 bucz CQ(VP9)=((CRF(X264.X265)*63))/51

./vpxenc --output=RrreadySteadyGo_1920x1080_120fps_420_8bit_. webm --codec=vp9 --passes=2 --good -v --i420 --width=1920 --height=1080 --profile=0 --fps=50000/1001 --input-bit-depth=8 /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --bit-depth=8 --end-usage=q --limit=100 --cq-level=24 --tile-columns=4 --threads=4 --cpu-used=4

bitrate = 12804 kb/s

[rockerovo]

./vpxenc --output=ReadySteadyGo_1920x1080_120fps_420_8bitzzz. webm --codec=vp9 --passes=2 --good -v --i420 --width=1920 --height=1080 --profile=0 --fps=50000/1001 --auto-alt-ref=1 --input-bit-depth=8 --tile-columns=4 /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --bit-depth=8 --end-usage=q --limit=100 --min-q=10 --max-q=10 --threads=4 --cpu-used=4 --cq-level=10
Warning: Bad quantizer values. Quantizer values should not be equal, and should differ by at least 8.
1 encoder configuration warning(s). Continue? (y to continue) y

bitrate = 24089 kb/s

[rockerovo]

you are right

when im using qp = 30

x264 --frames 100 --profile high --preset medium -o x264_10.264 --input-csp i420 --output-csp i420 --input-depth 8 --output-depth 8 --input-res 1920x1080 --fps 50 --verbose --dump-yuv x264_10.yuv /home/siraj/Desktop/Project/Samples/1080p/ReadySteadyGo_1920x1080_120fps_420_8bit_YUV.yuv --qp=30

bitrate = 5399.16 kb/s

x265 : 4417.25 kb/s

for vp9 : 5846 kb/s

[LigH.de]

And for a different movie, you will get three more different bitrates.

[pandy]

I know there is Constant Quantizer (Q) and you can select it by using --end-usage=q and -min-q=10 --max-q=10

For ffmpeg Google recommends: https://developers.google.com/media/vp9/bitrate-modes/ , i would give a chance to verify how your encoding parameters for "WebM Project VP9 Encoder v1.7.0 " works, did they producing same result as ffmpeg?

-c:v vp9 -g 1 -b:v 0 -crf 0 -quality good -speed 0 -lossless 1

(lossless mode intra vp9)

Next topic is then how you perform constant quantizer check - are you using vp9 analyser?