[mythtv-users] Cannot max out CPU usage on HLS transcode

[Raymond Wagner]

On 10/17/2012 02:31, Jim Downie wrote:
>> I agree with Raymond's assessment in another reply that you may be
>> running into a limit due to the single threaded decoder. The
>> encoder will use up to 8 threads if you set the
>> HTTPLiveStreamThreads setting, with the default being 2 threads. I
>> have the code set to use 8 slices in avformatwriter.cpp which
>> limits the thread usage to 8 even if you set HTTPLiveStreamThreads
>> higher.
>
> Can this limit be increased in a future update to use more slices (if
> its being controlled through the HTTPLiveStreamThreads setting)?

It can be increased if there is value to doing so, which at this point
is limited to multi-socket servers with 12+ cores. Assuming your issue 
is a decoding bottleneck, the only thing that would help would be a 
future version of MythTV switching to ffmpeg-mt, which performs 
pipelined decoding of multiple successive frames simultaneously. 
Alternatively, you could use more intensive encoding parameters, such 
that the encoding threads are actually doing something other than 
sitting idle waiting for frames from the decoder.