LibGfx/JPEG: Compute optimized Huffman tables in the encoder #26323
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This will allow us to insert a pass to compute the most optimal Huffman tables for this image.
Doing this a bit out of the natural order will allow us to compute optimized huffman tables. Note that we need to set the quantizations tables before calling `fdct_and_quantization()`. So let's move this step to an explicit method call in `add_image()`.
Compared to master, this gives approximatively 10% size reduction on buggie.png and a 4% reduction on `big_image.jpg`.
LucasChollet
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nico
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| if (mode == Mode::CMYK || i < 3) { | ||
| TRY(encode_dc(component, i)); | ||
| TRY(encode_ac(component, i)); | ||
| } |
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(nit: i find the unrolled version on the lhs easier to understand…)
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(first commit reminds me a bit of 5th commit of #24633 :)) |
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Here are some before/after on the images:
I expected performance to be worse as we're doing more work, but it turns out that this reduces the runtime for
big_image.jpg @ q100by 12%.