ProRes
Apple ProRes encoder.
FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder. The used encoder can be chosen with the -vcodec
option.
Private Options for prores-ks
- 'profile integer'
-
Select the ProRes profile to encode
- 'proxy'
- 'lt'
- 'standard'
- 'hq'
- '4444'
- '4444xq'
- 'lt'
- 'proxy'
- 'quant_mat integer'
-
Select quantization matrix.
- 'auto'
- 'default'
- 'proxy'
- 'lt'
- 'standard'
- 'hq'
- 'default'
If set to auto, the matrix matching the profile will be picked. If not set, the matrix providing the highest quality, default, will be picked.
- 'auto'
- 'bits_per_mb integer'
-
How many bits to allot for coding one macroblock. Different profiles use between 200 and 2400 bits per macroblock, the maximum is 8000.
- 'mbs_per_slice integer'
-
Number of macroblocks in each slice (1-8); the default value (8) should be good in almost all situations.
- 'vendor string'
-
Override the 4-byte vendor ID. A custom vendor ID like apl0 would claim the stream was produced by the Apple encoder.
- 'alpha_bits integer'
-
Specify number of bits for alpha component. Possible values are 0, 8 and 16. Use 0 to disable alpha plane coding.
Speed considerations
In the default mode of operation the encoder has to honor frame constraints (i.e. not produce frames with size bigger than requested) while still making output picture as good as possible. A frame containing a lot of small details is harder to compress and the encoder would spend more time searching for appropriate quantizers for each slice.
Setting a higher 'bits_per_mb' limit will improve the speed.
For the fastest encoding speed set the 'qscale' parameter (4 is the recommended value) and do not set a size constraint.