[FFmpeg-devel] Question about av_frame_is_writable
jdelvare at suse.de
Sat Dec 12 10:06:40 CET 2015
Can av_frame_is_writable() ever return 1, and if so, when?
Context: I am testing corner cases of the delogo filter. To my
surprise, even for a simple test case such as:
$ ffmpeg -f lavfi -i "color=color=white:size=24x24" -frames:v 1 -vf "delogo=7:3:8:8" -f image2 debug.png
av_frame_is_writable() returns 0, which disables direct mode of the
delogo filter and forces the allocation of a new buffer. My
understanding was that we were trying to avoid allocation and data copy
as much as possible, for performance reasons, and with such a simple
filter graph I can't see why we can't modify the video data in-place.
Can someone enlighten me?
SUSE L3 Support
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