Black isn't always just memset(ptr, 0, size). Limited YUV in particular requires relatively non-obvious values, and filling a frame with repeating 0 bytes is disallowed in some contexts. With component sizes larger than 8 or packed YUV, this can become relatively complicated. So having a generic function for this seems helpful. In order to handle the complex cases in a generic way without destroying performance, this code attempts to compute a black pixel, and then uses that value to clear the image data quickly by using a function like memset. Common cases like yuv410p10 or rgba can't be handled with a simple memset, so there is some code to fill memory with 2/4/8 byte patterns. For the remaining cases, a generic slow fallback is used. Signed-off-by: Anton Khirnov <anton@khirnov.net> Merged from Libav commit 45df7adc1d9b7.
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| @@ -15,6 +15,9 @@ libavutil: 2015-08-28 · 14 unmodified lines | |||
| 15 | 15 | ||
| 16 | API changes, most recent first: | 16 | API changes, most recent first: |
| 17 | 17 | ||
| 18 | 2017-08-08 - xxxxxxx - lavu 55.72.100 - imgutils.h | ||
| 19 | Add av_image_fill_black(). | ||
| 20 | |||
| 18 | 2017-08-08 - xxxxxxx - lavu 55.71.100 - frame.h | 21 | 2017-08-08 - xxxxxxx - lavu 55.71.100 - frame.h |
| 19 | Add av_frame_apply_cropping(). | 22 | Add av_frame_apply_cropping(). |
| 20 | 23 | ||