[FFmpeg-devel] [RFC] ffmpeg: Improved the performance of 1:N for adaptive bitrate scenario.

James Almer jamrial at gmail.com
Mon Nov 12 20:37:05 EET 2018


On 11/12/2018 3:28 PM, Michael Niedermayer wrote:
> On Sun, Nov 11, 2018 at 07:07:18PM +0800, Jun Zhao wrote:
>> Improved the performance of 1 decode + N filter graphs and adaptive
>> bitrate scenario.
>>
>> With new option "-abr_pipeline"
>> 1. It enabled multiple filter graph concurrency, which bring above
>> about 5%~20% improvement in some 1:N scenario by CPU or GPU
>> acceleration
>> 2. Next step will continue to improve the concurrency of complex
>> filter graph which can support high efficiency of filter net
>>
>> Below are some test cases and test result as reference.
>> (Hardware platform: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz)
>> (Software: Intel iHD driver - 16.9.00100, CentOS 7)
>>
>> Command for Intel GPU acceleration case, 1 decode to N scaling:
>> ffmpeg -vaapi_device /dev/dri/renderD128 -hwaccel vaapi \
>>     -hwaccel_output_format vaapi \
>>     -i ~/Videos/1920x1080p_30.00_x264_qp28.h264 \
>>     -vf "scale_vaapi=1280:720:format=nv12,hwdownload" \
>>     -pix_fmt nv12 -f null /dev/null \
>>     -vf "scale_vaapi=720:480:format=nv12,hwdownload" \
>>     -pix_fmt nv12 -f null /dev/null \
>>     -abr_pipeline
>>
>>     test results:
>>                 2 scale
>>     Improved       ~34%
>>
>> Command for CPU only 1 decode to N scaling:
>> ffmpeg -i ~/Videos/1920x1080p_30.00_x264_qp28.h264 \
>>     -vf "scale=1280:720" -pix_fmt nv12 -f null /dev/null \
>>     -vf "scale=720:480" -pix_fmt nv12 -f null /dev/null \
>>     -abr_pipeline
>>
>>     test results:
>>                 2 scale
>>     Improved       ~25%
>>
>> Command for 1:N transcode by GPU acceleration:
>> ./ffmpeg -vaapi_device /dev/dri/renderD128 -hwaccel vaapi \
>>     -hwaccel_output_format vaapi \
>>     -i ~/Videos/1920x1080p_30.00_x264_qp28.h264 \
>>     -vf "scale_vaapi=1280:720" -c:v h264_vaapi -f null /dev/null \
>>     -vf "scale_vaapi=720:480" -c:v h264_vaapi -f null /dev/null \
>>     -abr_pipeline
>>
>>     test results:
>>                 2 scale+enc
>>     Improved      ~6.1%
>>
>> Signed-off-by: Wang, Shaofei <shaofei.wang at intel.com>
>> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
>> ---
>>  fftools/ffmpeg.c        |  236 ++++++++++++++++++++++++++++++++++++++++++++---
>>  fftools/ffmpeg.h        |   12 +++
>>  fftools/ffmpeg_filter.c |    6 +
>>  fftools/ffmpeg_opt.c    |    6 +-
>>  4 files changed, 246 insertions(+), 14 deletions(-)
> 
> this breaks build for mingw64
> 
> CC	fftools/ffmpeg_filter.o
> CC	fftools/ffmpeg.o
> src/fftools/ffmpeg_filter.c: In function ‘init_simple_filtergraph’:
> src/fftools/ffmpeg_filter.c:231:39: error: incompatible types when assigning to type ‘pthread_t’ from type ‘int’
>              ist->filters[i]->f_thread = 0;
>                                        ^
> make: *** [fftools/ffmpeg_filter.o] Error 1
> make: *** Waiting for unfinished jobs....
> src/fftools/ffmpeg.c: In function ‘pipeline_reap_filters’:
> src/fftools/ffmpeg.c:1534:5: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
>      OutputStream *ost = output_streams[i];
>      ^
> src/fftools/ffmpeg.c: In function ‘do_streamcopy’:
> src/fftools/ffmpeg.c:2177:5: warning: ‘av_copy_packet_side_data’ is deprecated (declared at src/libavcodec/avcodec.h:4423) [-Wdeprecated-declarations]
>      av_copy_packet_side_data(&opkt, pkt);
>      ^
> src/fftools/ffmpeg.c: In function ‘filter_pipeline’:
> src/fftools/ffmpeg.c:2405:5: warning: ‘return’ with no value, in function returning non-void [enabled by default]
>      return;
>      ^
> src/fftools/ffmpeg.c: In function ‘send_frame_to_filters’:
> src/fftools/ffmpeg.c:2444:42: error: invalid operands to binary == (have ‘pthread_t’ and ‘int’)
>              if(ist->filters[i]->f_thread == 0) {

How old is your mingw64 toolchain? It should be using the w32threads
wrapper or some library like winpthreads, but it's not.

In any case, the issue is a missing #if HAVE_THREADS check for the newly
added ffmpeg.h fields.


More information about the ffmpeg-devel mailing list