search

google / compare-codecs

Apache License 2.0
49 stars 23 forks source link

use the recommended command options for openh264 #52

Closed sijchen closed 9 years ago

sijchen commented 9 years ago

1, Suggest not to use the options -maxbrTotal and -lmaxb in performance tests like this, since these two will put stricter control on bit rate. Given the focus of openh264 is more on paced vbr, suggest not to use these constrictions in performance testing. Setting them to 0 which mean unspecified if there is no need to set them. 2, '-fs 0' can be used to disable EnableFrameSkip, regarding that this is PSNR test I use a constant here. Seems there is no such variable in 'parameters'? Pls let me know if I should use a variable for this rather than a constant. Thx.

alvestrand commented 9 years ago

Wonderful to have your input! Just some questions - in case we can get rid of another hack by doing this.

alvestrand commented 9 years ago

BTW, I'm running the tool with the changed configuration (take_snapshot followed by verify_scores --score openh264), and it seems to be saying "no change" for all clips tried so far. So it's likely a better configuration, but doesn't matter for these clips in this configuration.

sijchen commented 9 years ago

1, Yes it is possible that the setting won't affect the current test sets you are using, if the encoding of the given sequence does not touch the upper-bound of max-br. But I will suggest setting it like this since the constraint is not needed, and on some other test set this parameter may make a difference. 2, with '-fs 0' the editing of EnableFrameSkip in cfg file can be saved.

BTW, the element which will really make a difference in comparison results is in this issue: https://github.com/google/compare-codecs/issues/53

sijchen commented 9 years ago

The option of AdaptiveQuantization will have negative impact on rate control. And the frame rate setting is needed for the rate control to work correctly.

alvestrand commented 9 years ago

I forgot to go through the formalities... can you create a new PR that adds you to the CONTRIBUTORS file, and either you or your organization to the AUTHORS file? This will make the lawyers happier...