Ugly fades.

[J_Darnley]

It's not the fact that you use a qpfile that will interfere with VBV and other restrictions, it is what you do with it. If you ask for 100 I-frames then VBV could start killing the picture because I-frames are large. This may also not work with Blu-Ray restrictions too. What is the minimum key-frame interval that is usually used?

[moviefan]

I use --min-keyint 1 and --keyint 24, --vbv-bufsize 30000 and --vbv-maxrate 24000. In fact, I am not keen on inserting I-frames only, but this is ONE possibility to increase the quality of that fade-in scene. The thing is that I don't see any other way to achieve that... Otherwise I am open for any ideas, but I'm afraid this problem has been discussed here without a helping result. So do 100 I-frames in a row interfere with said compliance considering the above mentioned settings?

Thanks for help!

[Dark Shikari]

I use --min-keyint 1 and --keyint 24, --vbv-bufsize 30000 and --vbv-maxrate 24000. In fact, I am not keen on inserting I-frames only, but this is ONE possibility to increase the quality of that fade-in scene. The thing is that I don't see any other way to achieve that... Otherwise I am open for any ideas, but I'm afraid this problem has been discussed here without a helping result. So do 100 I-frames in a row interfere with said compliance considering the above mentioned settings?

Thanks for help!Interfere with compliance? No. Interfere with quality? Maybe.

[nm]

I use --min-keyint 1 and --keyint 24, --vbv-bufsize 30000 and --vbv-maxrate 24000. In fact, I am not keen on inserting I-frames only, but this is ONE possibility to increase the quality of that fade-in scene. The thing is that I don't see any other way to achieve that...
How about just encoding the movie without psy-rd (the fade scene looked fine to me that way), or alternatively, use CRF instead of 2-pass?

[moviefan]

Hm, CRF won't work since I aim at a specific target size. Encoding without psy-rd, I could try that but psy-rd keeps grain well - maybe disabling it result in worse grain retention, but I will definitely try! In case grain looks bad without psy-rd: Could I use the encode I have so far, which is very pleasing (except for that fading scene) and replace the fade by a CRF encode of it (and then without psy-rd)?

[Dark Shikari]

Hm, CRF won't work since I aim at a specific target size. Encoding without psy-rd, I could try that but psy-rd keeps grain well - maybe disabling it result in worse grain retention, but I will definitely try! In case grain looks bad without psy-rd: Could I use the encode I have so far, which is very pleasing (except for that fading scene) and replace the fade by a CRF encode of it (and then without psy-rd)?You could also try using the same encoding settings on both passes... that tends to help bitrate mispredictions with psy-RD. Usually just using subme 7/8x8dct on the first pass is sufficient though.

[nm]

You could also try using the same encoding settings on both passes... that tends to help bitrate mispredictions with psy-RD. Usually just using subme 7/8x8dct on the first pass is sufficient though.
Indeed, using subme 7 and 8x8dct on the first pass fixes the problem in moviefan's clip.

[moviefan]

@nm: Have you tried it? I will only be able in a couple of hours...

[nm]

@nm: Have you tried it? I will only be able in a couple of hours...
Yep. I was just experimenting with using zones on the clip: --zones 1,50,q=20 also helped to avoid the problem.
But DS's suggestion worked perfectly.

[moviefan]

Unfortunately and without explanation, the fading scene still contains ugly frames when I look at it frame by frame. It does look better with --8x8dct --subme 9 (which is what I use... 9 instead of 7 shouldn't harm quality right?) but compared to the rest of the movie, it still looks very ugly.

@nm: Could you please upload the encoded sample which you consider good looking now? Also please post your command line to check the difference in order to hopefully optimize mine. Thanks!

[nm]

Unfortunately and without explanation, the fading scene still contains ugly frames when I look at it frame by frame. It does look better with --8x8dct --subme 9 (which is what I use... 9 instead of 7 shouldn't harm quality right?) but compared to the rest of the movie, it still looks very ugly.
Yes, if I look at it frame-by-frame, the first 10-20 frames seem to exhibit some blocking, but I can't see the issue in normal playback even if I look for it.
If this still bothers you, try using a constant QP zone as I described above.

A sample (http://www.cs.helsinki.fi/u/mikkila/video/x264-r1070-fade-5mbps.264) with psy-rd 1.0:0.5. Rest of the parameters are same as yours. I'm not sure if I encoded this with subme 7 or 9 in the first pass, but that didn't seem to make a difference.