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Does this compression hit you mention also apply to encoders that use for example CUDA on Nvidia GPUs? With these there definitely are significant differences i
by ttkari 7y ago
Does this compression hit you mention also apply to encoders that use for example CUDA on Nvidia GPUs? With these there definitely are significant differences in encoding speed between different GPUs.
- Youden 7y agoThere's no reason that using CUDA inherently leads to inferior compression but I'm not aware of a CUDA-accelerated encoder that's any good relative to a pure software encoder (or even NVENC, the pure hardware encoder on an NVIDIA GPU).
- FullyFunctional 7y agoWell, it's not that simple. The CUDA model has a inherent penalty for divergent thread behavior, that is, when all threads do the same, peak performance is attained. If they all follow a different path, the result can be disastrous. The relevance to media encoding is that the higher profiles do a lot of data dependent special casing. It's no accident that the earliest CUDA Video codecs only handled the base profile. This also hurts a CPU implementation but much less.