[x264-devel] Current x264 worse than before?

[Jason Garrett-Glaser]

On Mon, Apr 21, 2008 at 12:00 AM, ??? <wu.pengcheng at pixela-china.com> wrote:
> I ran a test comparing x264_r819 and r736, using all default settings encoding 720x576 sequencies on a Core II 1.8G computer. My result was like r819 has lower PSNRs AND lower speed, and I think the result has statistical significance. Any thoughts? -Peter

The drop in PSNR is due to the addition of adaptive quantization,
which lowers PSNR but generally increases SSIM and visual quality.

If there is a speed drop, it is likely again due to the addition of
adaptive quantization, which results in far fewer skips (due to
improved quality in flat background areas).

In everything else, however, x264 has gotten vastly faster:

rev 736 (frames in parallel)
----------------------------

Threads				6 (0)
720p50_mobcal_ter.yuv		20.73
720p50_parkrun_ter.yuv		21.40
720p50_shields_ter.yuv		19.13
foreman_cif.yuv			172.15

rev 798 (frames in parallel)
----------------------------

Threads				6 (0)
720p50_mobcal_ter.yuv		22.62
720p50_parkrun_ter.yuv		23.65
720p50_shields_ter.yuv		21.08
foreman_cif.yuv			192.03

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