x264 --fastdecode

[Anakunda]

Hello,

does this switch any good to unburden CPU for playback on phone device? I still think the video has little performance problems. If --fastdecode doesnot make the trick, what are other suggestions to optimize decoding without losing much video quality?

[J_Darnley]

--tune fastedecode already sets options which are fast to decode. If your phone can't keep up you will need to go further and reduce the frame size, frame rate, bitrate or a combination of these.

[Anakunda]

thanks for the answer.

To don't have to start new topic I put one more question here:
I determined that I have been accidentally converting all my DVD collection with --b-pyramid none parameter.
I wanted to ask if this option only does influence compression or quality too.
If it only impacts compression rate, what relative difference it makes using b-pyramid none versus normal, is it worth to re-rip my collection again with --b-pyramid normal option?

Thanks for answering

[poisondeathray]

I determined that I have been accidentally converting all my DVD collection with --b-pyramid none parameter.
I wanted to ask if this option only does influence compression or quality too.
If it only impacts compression rate, what relative difference it makes using b-pyramid none versus normal, is it worth to re-rip my collection again with --b-pyramid normal option?



compression and quality are inter-related

better compression at a given bitrate implies better quality :)

impossible to answer your last question, because it will vary by content. Some sources may benefit more than others

[Anakunda]

compression and quality are inter-related

better compression at a given bitrate implies better quality :)

impossible to answer your last question, because it will vary by content. Some sources may benefit more than others

I have meant with using Constant Ratefactor (--crf), so I assume (I hope) the b-pyramid only increased files size, without degrading overall video quality, but I'm not sure.

[poisondeathray]

I have meant with using Constant Ratefactor (--crf), so I assume (I hope) the b-pyramid only increased files size, without degrading overall video quality, but I'm not sure.

In theory , it should decrease file size , if it used b-pyramid . In practice, this isn't always what happens

remember , even if you use b-pyramid in the encoding settings, it doesn't necessarily mean the encode actually utilizes it to any extensive extent. Same with entering high numbers of ref frames or b-frames. Look at you encode logs to see if your source actually uses it with a given set of encode settings, and to what extent. You will see this varies a lot by source.

[Anakunda]

OK, so if I encoded in CRF mode, can I rely that disabling B-pyramids didnot harm the quality at all?
Thanks.

[poisondeathray]

OK, so if I encoded in CRF mode, can I rely that disabling B-pyramids didnot harm the quality at all?


It won't harm it per se , but it might have been better with b-pyramid. It might have made little to no difference. Again, it will vary by source. The only way to know for sure is to test it.

If you're still talking about device playback, some cannot play with b-pyramid