Is x264 Really Better Than Quick Sync?

[hogger129]

Hello all,

I am making some backups of my movies with Handbrake and I am just curious, is x264 really the way to go for this rather than QSV (Quick Sync)? I have tried both and I'm not sure I really can see a difference. But this being a heavily time-consuming process, I only want to do this once. Would QSV be considered "good enough," where the difference could only be seen in extreme examples, or is it pretty easy to tell?

If x264, do you guys prefer the Slow speed setting to Medium speed setting? I'm on an i7-4790 so I can accomplish either in a reasonable amount of time (typically between 2 and 4 hours).

Thanks.

PS, I am just watching them via computer, would I gain anything by converting the audio to AAC 5.1 other than prolonging the conversion process?

[jagabo]

QS on an i7-4790 is about the same quality as x264 at the veryfast preset. x264 at the medium or slow preset is better. Watch for posterization artifacts in shallow gradients and loss of small, low contrast detail (and noise). See the two clips in this post: https://forum.videohelp.com/threads/368914-24-fps-and-very-fast-STELLAR-DVD-rips-in-Han...=1#post2363323

[hogger129]

QS on an i7-4790 is about the same quality as x264 at the veryfast preset. x264 at the medium or slow preset is better. Watch for posterization artifacts and loss of small, low contrast detail (and noise).

Forgive me as I am not super experienced in video conversion, but what is posterization? Would that be like blacks not looking right? Also would I gain anything by converting the lossless HD audio to AAC instead of AC3 except for compatibility problems and smaller file size?

[Kerry56]

I've been using the Slow speed setting for my encodes as a general rule (Vidcoder though, not Handbrake). I usually do encodes overnight, so not an issue if it is a little bit longer encoding time.

Most people convert to AAC to get better compatibility with portable devices, and it has become the standard audio codec for MP4 files. AAC will be considerably smaller than the HD audio. I normally use MKV for small files, since they work in my tablet well, but if I were making MP4 of any size, I'd definitely use AAC.

Since your target device is a computer, you don't have to convert the audio at all if you don't mind the larger file size, and you are using MKV. The question is, will you ever want to use these files in something else?

I make 23gb backups in Blu-ray format for my HTPC using BD Rebuilder, and keep the HD audio most of the time.

[jagabo]

what is posterization?

http://www.dpreview.com/glossary/digital-imaging/posterization

It won't be as bad as in that example. I added a link to some actual x264 encodes in my previous post.

[hogger129]

what is posterization?

http://www.dpreview.com/glossary/digital-imaging/posterization

It won't be as bad as in that example. I added a link to some actual x264 encodes in my previous post.

Ahh ok. I think I have seen this quite a bit using QSV encoding. x264 seemed to do much better in that area. I always called it banding, but now I know the technical name is posterization.

Thanks for yours and Kerry56's help.

[jagabo]

Yes, it's also called banding.

[hogger129]

Yes, it's also called banding.

Thank you for clarifying. My next question is if there would be any advantage converting the lossless track to AAC 5.1 instead of Dolby Digital 5.1? Should that be asked in a separate discussion in the Audio section?

[jagabo]

My next question is if there would be any advantage converting the lossless track to AAC 5.1 instead of Dolby Digital 5.1?

In theory, at the same bitrate, aac will sound a little better than ac3. But if you allow sufficient bitrate, say 384 kbps or more, you won't be able to tell the difference between the two except in some rare cases. You'll find fewer devices can play 5.1 aac (since it was limited to two tracks for such a long time) except for MP4 files where ac3 is a fairly recent addition.

[hogger129]

Thanks for your help guys.

After doing a few encodes with x264 Slow, CRF 18, it's just ridiculous how good they look compared to the source and I did feel they looked better than Intel Quick Sync encodes on my display.

I decided to just stay with 640 kbps AC3 5.1 for the audio track as this seems to be compatible with just about anything.

I can now put this issue to rest.

Thanks again.