Re: [rtcweb] New VP8 vs H.264 tests uploaded

> Was there any specific parameter or parameter set you were wondering about?

--nal-hrd cbr and --bitrate, who suggested those? They were not part of the suggested<http://mailman.videolan.org/pipermail/x264-devel/2013-March/009920.html> settings from x264-devel.

Mo

From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On Behalf Of Harald Alvestrand
Sent: Thursday, April 04, 2013 9:31 AM
To: rtcweb@ietf.org
Subject: Re: [rtcweb] New VP8 vs H.264 tests uploaded

On 04/04/2013 10:53 AM, Sergio Garcia Murillo wrote:
Hi Adrian,

Could you explain how the encoding parametrization is comparable?

x264 --nal-hrd cbr --vbv-maxrate ${rate} --vbv-bufsize ${rate} \
      --vbv-init 0.8 --bitrate ${rate} --fps ${frame_rate} \
      --profile baseline --no-scenecut --keyint infinite --preset veryslow \
      --input-res ${width}x${height} \
      --tune psnr \
      -o ./encoded_clips/h264/${clip_stem}_${rate}kbps.mkv ${filename} \
      2> ./logs/h264/${clip_stem}_${rate}kbps.txt

vs:

 ./bin/vpxenc --lag-in-frames=0 --target-bitrate=${rate} --kf-min-dist=3000 \
      --kf-max-dist=3000 --cpu-used=0 --fps=${frame_rate}/1 --static-thresh=0 \
      --token-parts=1 --drop-frame=0 --end-usage=cbr --min-q=2 --max-q=56 \
      --undershoot-pct=100 --overshoot-pct=15 --buf-sz=1000 \
      --buf-initial-sz=800 --buf-optimal-sz=1000 --max-intra-rate=1200 \
      --resize-allowed=0 --drop-frame=0 --passes=1 --good --noise-sensitivity=0 \
      -w ${width} -h ${height} ${filename} --codec=vp8 \
      -o ./encoded_clips/vp8/${clip_stem}_${rate}kbps.webm \
      &>./logs/vp8/${clip_stem}_${rate}kbps.txt

Both have the same target bitrate and the same resolution, and neither generates periodic keyframes.

Apart from that, I think they are comparable by virtue of being the parameters that were recommended for this test by people who like this particular codec implementation.

Was there any specific parameter or parameter set you were wondering about?

Best regards
Sergio

El 03/04/2013 18:20, Adrian Grange escribió:
We have uploaded a new set of test results comparing VP8 to H.264. This latest set contains fixes for some of the problems in the previous set. We would like to extend our thanks to those who made suggestions as to how we could improve our methodology and encourage suggestions as to how we can make further improvements.

In these tests we run x264 with the "veryslow" preset and VP8 with the "good, speed 0" setting in an attempt to produce comparable results.

An overview of our results is available as follows:

- A Quality comparison (psnr): http://downloads.webmproject.org/ietf_tests/vp8_vs_h264_quality.html

- An Encode Speed comparison: http://downloads.webmproject.org/ietf_tests/vp8_vs_h264_speed.html

- A comparison of the aggregate time required to decode all of the clips in the test: http://downloads.webmproject.org/ietf_tests/vp8vsh264-decodetime.txt

All of our test scripts can either be downloaded from:
http://downloads.webmproject.org/ietf_tests/vp8_vs_h264.tar.xz
or checked out of our git/gerrit repository:
git clone http://git.chromium.org/webm/vpx_codec_comparison.git

The file README.txt, contained within, presents details of how to build and run the tests.

The compressed video files--the output from the quality tests--can also be downloaded:

VP8:
http://downloads.webmproject.org/ietf_tests/vp8_videos<http://downloads.webmproject.org/ietf_tests/vp8_videos/>/index.html

H.264:
http://downloads.webmproject.org/ietf_tests/h264_videos/index.html

Adrian Grange

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