[FFmpeg-devel] [PATCH 2/2] lavfi: make filter_frame non-recursive.

[James Almer]

On 11/27/2016 1:08 PM, Nicolas George wrote:
> A lot of changes happen at the same time:
> 
> - Add a framequeue fifo to AVFilterLink.
> 
> - split AVFilterLink.status into status_in and status_out: requires
>   changes to the few filters and programs that use it directly
>   (f_interleave, split, filtfmts).
> 
> - Add a field ready to AVFilterContext, marking when the filter is ready
>   and its activation priority.
> 
> - Add flags to mark blocked links.
> 
> - Change ff_filter_frame() to enqueue the frame.
> 
> - Change all filtering functions to update the ready field and the
>   blocked flags.
> 
> - Update ff_filter_graph_run_once() to use the ready field.
> 
> - buffersrc: always push the frame immediately.
> 
> Signed-off-by: Nicolas George <george at nsup.org>
> ---
>  libavfilter/avfilter.c         | 457 ++++++++++++++++++++++++++++++++++-------
>  libavfilter/avfilter.h         |  71 +++++--
>  libavfilter/avfiltergraph.c    |  53 ++---
>  libavfilter/buffersink.c       |  21 +-
>  libavfilter/buffersrc.c        |   6 +-
>  libavfilter/f_interleave.c     |   8 +-
>  libavfilter/internal.h         |   6 +
>  libavfilter/split.c            |   5 +-
>  libavfilter/tests/filtfmts.c   |   3 +
>  libavfilter/vf_extractplanes.c |   6 +-
>  10 files changed, 493 insertions(+), 143 deletions(-)

This patch made audio encoding extremely slow.

time ./ffmpeg -i INPUT.wav -c:a tta -f null -

Before
size=N/A time=00:00:22.98 bitrate=N/A speed= 373x
video:0kB audio:1272kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
real    0m0.089s
user    0m0.000s
sys     0m0.000s

After
size=N/A time=00:00:22.98 bitrate=N/A speed=2.29x
video:0kB audio:1272kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
real    0m10.087s
user    0m0.015s
sys     0m0.000s

CPU usage for the latter is almost zero during the entire 10 seconds. And it can be reproduced
with pretty much any encoder.