Investigate using "optimize_coding" when encoding to JPEG |
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Issue descriptionSee https://github.com/bither/bither-android-lib/blob/master/REASON.md This project suggests that using "optimize_coding" when encoding to JPEG will result in a higher quality image with negligible performance/storage penalties. If that is true, we should allow using the feature. Brought to the Skia team's attention in skia-discuss here: https://groups.google.com/forum/#!topic/skia-discuss/p0IcyBoU8P0
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Jan 15 2016
My testing more-or-less agrees with the last three comments on the skia-discuss thread -- the image quality is identical with and without optimize_coding (as far as I can tell) and the image size is 10-30% smaller (I found a bigger savings than 5-10% as stated in the thread). Ignoring memory and CPU cost, enabling this flag is a win (and given that my phone is now more powerful than my laptop, we probably can ignore memory and CPU cost). I did not measure memory, but optimize_coding seems to increase CPU time by 2-3x. sample image 1 (RGB gradients): default (80): 2.5x slower, 34% smaller quality 0: 1.7x slower, 52% smaller quality 20: 2.1x slower, 55% smaller quality 40: 2.3x slower, 37% smaller quality 60: 2.5x slower, 36% smaller quality 100: 3.9x slower, 22% smaller sample image 2 (photo): default (80): 2x slower, 8% smaller quality 0: 1.5x slower, 49% smaller quality 20: 1.7x slower, 22% smaller quality 40: 1.9x slower, 15% smaller quality 60: 1.9x slower, 11% smaller quality 100: 2x slower, 9% smaller
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Jan 15 2016
The following revision refers to this bug: https://skia.googlesource.com/skia.git/+/0a35620a16b368356888d15771392fb00cbb777d commit 0a35620a16b368356888d15771392fb00cbb777d Author: benjaminwagner <benjaminwagner@google.com> Date: Fri Jan 15 02:13:32 2016 Add optimize_coding setting for JPEG encoding. Produces smaller encoded output at the expense of encoding time. No visual differences. sample image 1 (RGB gradients): default (80): 2.5x slower, 34% smaller quality 0: 1.7x slower, 52% smaller quality 20: 2.1x slower, 55% smaller quality 40: 2.3x slower, 37% smaller quality 60: 2.5x slower, 36% smaller quality 100: 3.9x slower, 22% smaller sample image 2 (photo): default (80): 2x slower, 8% smaller quality 0: 1.5x slower, 49% smaller quality 20: 1.7x slower, 22% smaller quality 40: 1.9x slower, 15% smaller quality 60: 1.9x slower, 11% smaller quality 100: 2x slower, 9% smaller BUG= skia:3460 GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1589593002 Review URL: https://codereview.chromium.org/1589593002 [modify] http://crrev.com/0a35620a16b368356888d15771392fb00cbb777d/src/images/SkImageDecoder_libjpeg.cpp
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Jan 15 2016
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Comment 1 by benjamin...@google.com
, Jan 13 2016