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Old 11th August 2009, 18:49   #21  |  Link
LoRd_MuldeR
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Quote:
Originally Posted by Chengbin View Post
Could the quality difference be the fact that x264 does not use slices, where the commercial encoders must?
I wouldn't expect slices to make such a difference. Not at BD bitrates (36 Mbit/s).
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Old 11th August 2009, 20:51   #22  |  Link
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The link given by LoRd_MuldeR applies to SD (480p). 1080p with 4 slices will suffer a slightly lower PSNR loss than 480p with 2 slices, thus 0.038dB, which roughly amounts to a 0.8% bitrate loss at same quality.
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Old 11th August 2009, 22:26   #23  |  Link
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@neuron2, where you find that blu-ray specs?
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Old 11th August 2009, 22:56   #24  |  Link
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I have it through my employer as we implement decoders and players. Sorry, but I cannot re-distribute it. I can answer questions on the spec though.
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Old 11th August 2009, 23:19   #25  |  Link
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Quote:
Originally Posted by neuron2 View Post
I have it through my employer as we implement decoders and players. Sorry, but I cannot re-distribute it. I can answer questions on the spec though.
Can you just list the lack's of x264 that need to became full Blu-ray compatible, and point developers what is primary?
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Old 11th August 2009, 23:21   #26  |  Link
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Originally Posted by shon3i View Post
Can you just list the lack's of x264 that need to became full Blu-ray compatible, and point developers what is primary?
I have the spec as well.
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Old 11th August 2009, 23:25   #27  |  Link
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If a developer wants to contact me privately about it, the appropriate information can be provided.

EDIT: Dark already has it, so that's the main man.
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Old 11th August 2009, 23:34   #28  |  Link
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Quote:
Originally Posted by Dark Shikari View Post
I have the spec as well.
So you can already tell whether there are any other problems with BD compliance in x264, in addition to the known slices issue?
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Old 11th August 2009, 23:36   #29  |  Link
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Originally Posted by Dark Shikari View Post
I have the spec as well.
then why, not make x264 to be blu-ray compatible finaly? Last time when i asked you, you say that you do not have to specification because they are hide specs from public.
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Old 11th August 2009, 23:47   #30  |  Link
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Originally Posted by shon3i View Post
then why, not make x264 to be blu-ray compatible finaly? Last time when i asked you, you say that you do not have to specification because they are hide specs from public.
I don't have the whole spec, only part of it, and you pretty much already know what that part contains (VBV limits, 3 B-frames, no P-frames referencing B-frames, GOP size, slicing, etc).
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Old 12th August 2009, 04:26   #31  |  Link
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Very interesting - but according to x264, Level 4.0 has an upper bitrate limit of 25mbps, which I'd like to avoid.
25 Mbps is really a very high bitrate for 1080p24 H.264! using single-slice x264 with good settings. I'd expect Level 4.0 x264 with 25 Mbps peaks to be transparent for almost all real-world film content. 1080i30 without MBAFF, could be an issue, but 24p should be just fine. HD DVD titles looked great with older encoders, shorter GOPs, and similar or even lower peaks (one highly rated title was VC-1 with 13 Mbps ABR and 19 Mbps PBR).

Remember Blu-ray's peak bitrate was defined for MPEG-2 applications. It's rather overkill for modern codecs.
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Old 12th August 2009, 06:05   #32  |  Link
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Originally Posted by benwaggoner View Post
Remember Blu-ray's peak bitrate was defined for MPEG-2 applications. It's rather overkill for modern codecs.
My thinking exactly. I'm just a noob in encoding myself but seeing as SD content has 720x576=414 720 pixels to be delivered by MPEG-2 on standard DVD at peak video bitrates ~9 Mbps I would assume that HD material consisting of 1920x1080=2 073 600 pixels cannot require more than 5 times higher bitrate ~45 Mbps with same encoder used.
Now take into account we may use H.264 instead of older MPEG-2 and necessary video bitrate can be halved for the same visual quality I suppose.
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Old 12th August 2009, 12:00   #33  |  Link
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Originally Posted by neuron2 View Post
I have it through my employer as we implement decoders and players. Sorry, but I cannot re-distribute it. I can answer questions on the spec though.
Ok, i have several questions:

1. What is max allowed vbv-buffersize and vbv-maxrate for Level 4.0 from blu-ray specification (i.e for 4.1 are 30000/40000 buffer/maxrate), not H264.
2. So definitly L 4.0 dosen't require slices? can be then L 4.0 video primary video?
3. What is max allowed vbv-buffersize and vbv-maxrate for Level 3.2 from blu-ray specification for SD content, and what resoultion and fps allowed for SD, and is L 3.2 maximum for SD?
4. Is there anything about BD5/9 and special restrictions such as VBV or other?


That is for now.

Thanks.
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Old 12th August 2009, 13:16   #34  |  Link
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Originally Posted by benwaggoner View Post
25 Mbps is really a very high bitrate for 1080p24 H.264! using single-slice x264 with good settings. I'd expect Level 4.0 x264 with 25 Mbps peaks to be transparent for almost all real-world film content. 1080i30 without MBAFF, could be an issue, but 24p should be just fine. HD DVD titles looked great with older encoders, shorter GOPs, and similar or even lower peaks (one highly rated title was VC-1 with 13 Mbps ABR and 19 Mbps PBR).

Remember Blu-ray's peak bitrate was defined for MPEG-2 applications. It's rather overkill for modern codecs.
I thought many Blu-ray's even at mid to high 20mbps look "not that good", as in lack of fine detail

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Old 12th August 2009, 13:23   #35  |  Link
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Quote:
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I thought many Blu-ray's even at mid to high 20mbps look "not that good", as in lack of fine detail
That's probably not the result of the bitrate, but a result of bad encoders and/or bad authoring
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Old 12th August 2009, 14:34   #36  |  Link
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Originally Posted by LoRd_MuldeR View Post
That's probably not the result of the bitrate, but a result of bad encoders and/or bad authoring
Therefore because of these bad encoders, you're lacking bitrate even though you have 25-30mbps. Therefore you're not getting "transparency"

Didn't Dark Shikari say even with x264, you need a lot more than 25mbps to reach transparency on 1080p videos (from a master)?

Last edited by Chengbin; 12th August 2009 at 14:40.
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Old 12th August 2009, 15:35   #37  |  Link
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Didn't Dark Shikari say even with x264, you need a lot more than 25mbps to reach transparency on 1080p videos (from a master)?
This is highly source dependent. I'm pretty sure for most sources you will be fine with x264 and much lower bitrates...
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Old 12th August 2009, 16:20   #38  |  Link
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Dark Shikari, do you mind clarifying this quote in terms of what kind of source are you referring to?

Quote:
x264 would require significantly more bitrate for transparency if encoding from a lossless source than from a Blu-ray. Blu-rays generally seem to have very little high-frequency content, almost as if they were lowpassed. I wouldn't be surprised if they were--and even if they aren't, the quantizatoin matrices they use often do so for them anyways.
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Old 12th August 2009, 16:26   #39  |  Link
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He mans that if you were encoding from an original lossless source ("Master"), then you would need significant more bitrate to retain all detail, because there is so much detail/grain in that source.

However we usually don't have access to such sources. What we have are BluRay's, which have already been filtered and compressed in a lossy way. Many detail is already gone for good when we get the data!

Re-encoding such lossy sources requires less bitrate to retain all details (the details that are still there) for obvious reasons...
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Last edited by LoRd_MuldeR; 12th August 2009 at 16:35.
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Old 12th August 2009, 16:40   #40  |  Link
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LoRd_MuldeR, I see you didn't finish reading my post, I said "from a master".

Anyway, I'm very excited to see what Lyris can do with his project using x264. BTW, p_l_e_a_s_e use the full 50GB of the disk. I've seen so many Blu-rays with low 20mbps bitrate and the disk still has 10-15GB free. But then truthfully this 40mbps cap is kind of a bottleneck. If you use high average bitrates (like Jumper's 33mbps), if you use bitrate viewer on it, it will probably look like CBR.

Last edited by Chengbin; 12th August 2009 at 16:44.
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