Fix JPEG decoding of an oddly encoded files on gen7/8 #530
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The VAAPI driver fails to decode JPEG if encoded data has component ID set to 255 (-1) and selector to 0 because this produces a wrong result of the final ID calculation since the component value is expanded to a 32bit signed integer by compiler instead of keeping it unsigned 8bit, thus the result is calculated as "0 - 255 + 1 = -254" instead of "0 - (-1) + 1 = 2". Example output from FFmpeg: ... [mjpeg @ 0x56156be1cc40] component 0 1:1 id: -1 quant:0 [mjpeg @ 0x56156be1cc40] component 1 1:1 id: 0 quant:1 [mjpeg @ 0x56156be1cc40] component 2 1:1 id: 1 quant:1 ... src/gen7_mfd.c:2549: gen7_mfd_jpeg_bsd_object: Assertion `0' failed. This patch fixes the offending integer expansion, JPEG is successfully decoded now. Signed-off-by: Dmitry Osipenko <[email protected]>
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@digetx could you provide a sample JPEG file that fails to decode? I have a Haswell CPU and cannot find any JPEGs that would fail to decode locally. |
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Don't have those files anymore. IIRC, the fix was inspired by the FFMPEG swdec code. |
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Intel VA-API driver fails to decode couple JPEG files for me because of the offending implicit u8->int32 expansion in the code of the driver. This PR fixes the implicit integer expansion and decoding works properly now.