Changes between Version 16 and Version 17 of Creating multiple outputs


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Timestamp:
Jun 4, 2016, 1:17:06 AM (18 months ago)
Author:
rogerdpack
Comment:

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  • Creating multiple outputs

    v16 v17  
    109109=== Parallel encoding === 
    110110 
    111 Outputting and re encoding multiple times in the same FFmpeg process will typically slow down to the "slowest encoder" in your list.  Some encoders (like libx264) perform their encoding "threaded and in the background" so they will effectively allow for parallel encodings, however audio encoding may be serial and become the bottleneck, etc.  It seems that if you do have any encodings that are serial, it will be treated as "real serial" by FFmpeg and thus your FFmpeg may not use all available cores.  One work around to this is to use multiple ffmpeg instances running in parallel, or possible piping from one ffmpeg to another to "do the second encoding" etc. 
     111Outputting and re encoding multiple times in the same FFmpeg process will typically slow down to the "slowest encoder" in your list.  Some encoders (like libx264) perform their encoding "threaded and in the background" so they will effectively allow for parallel encodings, however audio encoding may be serial and become the bottleneck, etc.  It seems that if you do have any encodings that are serial, it will be treated as "real serial" by FFmpeg and thus your FFmpeg may not use all available cores.  One work around to this is to use multiple ffmpeg instances running in parallel, or possible piping from one ffmpeg to another to "do the second encoding" etc.  Or if you can avoid the limiting encoder (ex: using a different faster one or just doing a raw stream copy) that might work.