[FFmpeg-user] A question about -benchmark_all

[rongyan]

Hi,
When I use -benchmark_all to record the x264 encoding time, I found the number for single thread is 16264711, while for the same bitstream, the number for the multithreads is 85186340. From the number , the multithreads use more time than the single thread, it does not make sense.
My command is like this:
single thread:
ffmpeg  -benchmark_all -i inputfile -vcodec libx264 -threads 0 .... outputfile.mp4
Multiple thread (the log file shows the number of threads is 128):
ffmpeg  -benchmark_all -i inputfile -vcodec libx264   .... outputfile.mp4
 
I look at the code, found the record update is before/after each thread schedule, so my question is whether or not  -benchmark_all can accurate record the encoding time? Or it in deed records the time not for encoding itself?

Appreciated if someone can help.

Rong Yan