Blender Git Commit Log

FFmpeg pixel format conversion improvements

FFmpeg expects Blender to feed it pixels in the output pixel format. If
the output pixel format is different than Blender's RGBA, a conversion
is needed (via FFmpeg's `sws_scale()` function). There were a few issues
with this conversion (and surrounding code) that are fixed in this
commit:

- When conversion was necessary a temporary buffer was allocated and
deallocated for every frame. This is now allocated once and re-used.
- Copying data to the buffer was done byte-for-byte. On little-endian
machines it is now done line-by-line using `memcpy` for a little speedup.
- The decision whether pixel format conversion is necessary is now
correctly done based on the pixel format Blender is actually using.
- The pixel format of the buffer sent to FFmpeg is no longer hard-coded
incorrectly to a fixed pixel format, but uses the actual output pixel
format. This is fixes T53058 properly, making RGB QTRLE export possible.
- I added some comments to make it clear which pixel format is referred
to (either Blender's internal format or the FFmpeg output format).

Combined these improvements not only correct a bug (T53058) but also
results in approximately 5% speed improvement (tested with a 117-frame
shot from Spring, loaded as PNGs in the VSE, encoding to h.264 with
preset 'realtime').

Reviewed By: brecht, sergey

Differential Revision: https://developer.blender.org/D5174