Variable Bitrate

[bphem3]

Does anyone know if CloneBD will receive an encoding option for variable bitrate?

 

[DeepSpace]

As there was another thread in the near past about hardware acceleration on AMD with no answer, they figured out that Elby seems to be not that active anymore. I think they were about to contact them, but I heared nothing since them. So I'm not sure if you will get an answer.
https://forum.redfox.bz/threads/at-the-risk-of-beating-a-dead-horse-clonebd-and-amd.81031/

 

[Fabian]

The used AAC encoder already has variable bitrate.

You may think of the old MP3 audio codec which added a feature for variable bitrate, meaning each audio frame adjusted its size to use the least size for same quality. With AAC, this feature is always implicit, it always behaves the same as the variable bitrate MP3.

For E-AC3 or DTS, this feature will not work. Both encoders would reset its internal state upon bitrate change. It would lead to noticeable audio artifacts. While it is possible to change that, it wouldn't change all the audio decoders that still will reset upon bitrate change.

 

[bphem3]

Thanks Fabian! That makes sense. Do you know if a variable bitrate could be supported for the main video bitrate? Anything remotely similar to what Netflix and Amazon use?

https://netflixtechblog.com/per-title-encode-optimization-7e99442b62a2

https://aws.amazon.com/media/tech/quality-defined-variable-bitrate-qvbr/

https://mux.com/per-title-encoding/

 

[Fabian]

My apologies, I assumed you were talking about audio variable bitrate; that's at least what my mind was thinking about.

We will actually add an option to encode quality based. With quality based encoding the output size is not predictable, but for a selected quality the file size will be minimal. The technical term is CRF encoding.