How to make 720x576 h264 video blu-ray compliant ?

[jpsdr]

Hello.

I've encoded a 720x576 25fps video with x264, and
set the AR to 4:3.
MeGUI accept the video, but when importing the .ves file in scenarist (v4.5), it refuse the video saying resolution is not BR compliant. For what i know, 720x576 25fps video is blu-ray compliant, so, i don't know what parameter is needed in x264 to make the video ok.

So, if someone know...

Thanks.

[shon3i]

720x576@25p is not Blu-Ray compilant resolution, you must use 50i, so encode as intelaced.

[jpsdr]

Ok... so, i just need to add the --interlaced command in x264 ?

[Fr4nz]

720x576@25p is not Blu-Ray compilant resolution, you must use 50i, so encode as intelaced.

Another way is to upscale the video to 720p and set the correct aspect-ratio accordingly.

[jpsdr]

No, i want to keep this resolution for storage reason, increasing to 720p => higher bitarate 'for nothing'...
-- interlaced seems ok, but now, scenarist says that Aspect_Ratio_idc is not supported... But, i've add the --sar 4:3 command in the encoding line...

[shon3i]

But, i've add the --sar 4:3 command in the encoding line... No you must add --sar 16:11 (for 16:9) or --sar 12:11 ( for 4:3) because that is allowed sar's for 576p video mode.

[jpsdr]

Thanks, actualy MUI + Import in scenarist works.
Now, i must do the final test : Multiplexing.
Later...
It realy sucks that video must be encoded interlaced, because it disable a lot of features in x264 !

[shon3i]

Now, i must do the final test : Multiplexing.
Later...It will work fine :) if you meet other settings such as VBV.

because it disable a lot of features in x264 ! in that case you should listen Fr4nz, and i agree with him in that case. I know upscaling is pointless but in this cases are very usefull.

I hope that once people understood that the HDDVD standard was better ;)

[jpsdr]

Theoricaly, i should have meet the other settings...

But, will i be able to keep the same quality with :
- 2 pass VBR 3000kb 720x576 video encoded in interlaced.
- 2 pass VBR 3000bk 720x576 upscaled to 1280x720 encoded in progressive.
(Maybe DS can answer to this...?)

Another tricky question : How can i enconde "properly" a 720x480 29.97p source ? (Anime of Claymore is like this).
From what i've checked, it seems that there is absolutely no 29.97p possibility !!!

[shon3i]

But, will i be able to keep the same quality with :
- 2 pass VBR 3000kb 720x576 video encoded in interlaced.
- 2 pass VBR 3000bk 720x576 upscaled to 1280x720 encoded in progressive.
(Maybe DS can answer to this...?)Progressive encoding is more effective than interlaced it requre less bitrate for same quality so you maybe get better quality even you have bigger resolution. You shold test and see what happen :) btw DS is not wizard to know what quality you get ;)

How can i enconde "properly" a 720x480 29.97p source ? (Anime of Claymore is like this).
From what i've checked, it seems that there is absolutely no 29.97p possibility !!! Same as 25p, 29.97i is aceptable too. allowed sar's are 10:11 and 40:33

[poisondeathray]

I think 720x480p29.97 is allowed as blu-ray secondary , but not legal for primary is it shon3i ?

[shon3i]

I think 720x480p29.97 is allowed as blu-ray secondary , but not legal for primary is it shon3i ?
Yes but you must have Primary Video least 720@50p, and secondary 576/480/p/i video have maximum 8mbps and Level 3.2 and maximum DBP of 3037.5. It's too complicated :)

[jpsdr]

A total hell !!!
Scenarist refused the 1280x720 25fps video encoded progressive, saying that value of the FrameRateCode is not supported in the BD standard !

[shon3i]

Well nobody say's that 720p25 is supported :) only 720 23.976,24,50,59.90 as progressive ;)

[jpsdr]

Thanks shon3i. I was using this : http://en.wikipedia.org/wiki/Blu-ray_Disc but it seems wrong.
Do you know a place were i can find all the video resolution, fps, i/p wich are supported ?

[jpsdr]

Mux in scenarist, of both video 576i and 720p Ok.
Good.

[SomeJoe]

Same as 25p, 29.97i is aceptable too. allowed sar's are 10:11 and 40:33

Can you please explain these aspect ratios? A 10:11 SAR does not sound correct for a 720x480 sample matrix intended for a 4:3 display. Generally I have seen 720x480 with an 8:9 SAR for 4:3 (this is technically not correct either, as it assumes the 720x480 would occupy the entire 4:3 picture area, which it doesn't).

The SAR that would be accurate to 1 pixel for 720x480 which was sampled at 13.5 MHz should be 72:79, which reflects the actual active picture area displayed at 4:3 (711x486).

[shon3i]

Can you please explain these aspect ratios? There is no explainations, it just written in Blu-Ray specification and is mandatory for 525/60 video.

[SomeJoe]

There is no explainations, it just written in Blu-Ray specification and is mandatory for 525/60 video.

OK, do you have a link to the BD specifications? I realize that the BD working group sells the actual spec book, but is there an online summary or condensed version? I would like to see how they have written this and if there is any rationale behind it.

[nm]

Can you please explain these aspect ratios? A 10:11 SAR does not sound correct for a 720x480 sample matrix intended for a 4:3 display.

I haven't read Blu-ray specs, but these values are implied by ITU-R BT.601. Take a look at this Wikipedia article: http://en.wikipedia.org/wiki/Pixel_aspect_ratio

[shon3i]

From BD Specs:

aspect_ratio_idc: The aspect_ratio_idc shall have one of the following values. This field shall be
present.
Sample aspect ratio 10:11
Sample aspect ratio 40:33

That's all about AR.

[SomeJoe]

I haven't read Blu-ray specs, but these values are implied by ITU-R BT.601. Take a look at this Wikipedia article: http://en.wikipedia.org/wiki/Pixel_aspect_ratio

Yes, the 10:11 value is implied by Rec. 601 for a 640x480 square pixel matrix, with a sampling frequency of 12+3/11 MHz.

The problem with this is that the defined sample matrix above doesn't sample the entire active picture area. By the analog definition of NTSC, the above sample matrix misses over 6 pixels of each horizontal scan line. Because the NTSC picture is defined as being displayed at 4:3 for the active picture area, the Rec. 601 sample matrix cannot be a 4:3 DAR. Thus, the 10:11 SAR is not correct.

For digital video, a 10:11 SAR would be correct for 704x480 video sampled at 13.5 MHz, but not 720x480.

[SomeJoe]

From BD Specs:

aspect_ratio_idc: The aspect_ratio_idc shall have one of the following values. This field shall be
present.
Sample aspect ratio 10:11
Sample aspect ratio 40:33

That's all about AR.


Thank you for posting what the spec says.

I do believe it's actually not correct, but if the spec demands it, then so be it.

[nm]

Yes, the 10:11 value is implied by Rec. 601 for a 640x480 square pixel matrix, with a sampling frequency of 12+3/11 MHz.

The problem with this is that the defined sample matrix above doesn't sample the entire active picture area. By the analog definition of NTSC, the above sample matrix misses over 6 pixels of each horizontal scan line. Because the NTSC picture is defined as being displayed at 4:3 for the active picture area, the Rec. 601 sample matrix cannot be a 4:3 DAR. Thus, the 10:11 SAR is not correct.

For digital video, a 10:11 SAR would be correct for 704x480 video sampled at 13.5 MHz, but not 720x480.

The same 10:11 SAR applies to both 704x480 and 720x480 digital sources. 704x480 can be considered the active area and the rest can be simply cropped away (http://forum.doom9.org/showthread.php?p=827399#post827399). 10:11 is probably the sample aspect ratio that professionals most often use when mastering digital 4:3 NTSC video and that's why it is mandated by Blu-ray specs.

If you want to get more confused, the 4:3 NTSC frame is actually supposed to be 710.85x486 pixels (http://www.iki.fi/znark/video/conversion/) (or more precisely, 484 and two half lines). When displaying video on a square-pixel display, 704x480 and 720x480 are centered to that frame and sample aspect ratio 4320:4739 is applied. Edges may be covered by overscan, the amount of which depends on the equipment/software. I don't know how often this 4320:4739 SAR is actually followed in practice.

[SomeJoe]

The same 10:11 SAR applies to both 704x480 and 720x480 digital sources. 704x480 can be considered the active area and the rest can be simply cropped away (http://forum.doom9.org/showthread.php?p=827399#post827399). 10:11 is probably the sample aspect ratio that professionals most often use when mastering digital 4:3 NTSC video and that's why it is mandated by Blu-ray specs.

If you want to get more confused, the 4:3 NTSC frame is actually supposed to be 710.85x486 pixels (http://www.iki.fi/znark/video/conversion/) (or more precisely, 484 and two half lines). When displaying video on a square-pixel display, 704x480 and 720x480 are centered to that frame and sample aspect ratio 4320:4739 is applied. Edges may be covered by overscan, the amount of which depends on the equipment/software. I don't know how often this 4320:4739 SAR is actually followed in practice.

My issue with most of the references and guides regarding NTSC sample and display aspect ratios is that most of them start quoting frame sizes in pixels and go from there, or start with ITU.601 recommendations, and none of them go back to the true reference for NTSC, which are the analog specs.

To me, you can talk about frame sizes, sample rates, SAR and DAR all day, but the thing that all of it must relate back to is this:

NTSC Frame Rate: 30000/1001 ~= 29.97002997 fps

System is 525 lines: 525 * 29.97002997 ~= 15734.266 kHz, the horizontal scan frequency.

Each scan line thus has a 1/15734.266 ~= 63.5555 microsecond period.

NTSC specs dictate that 10.9 microseconds of the horizontal scan period is the horizontal blanking interval, thus:

63.555 - 10.9 ~= 52.65555 microseconds of active picture area.

A scan line of active picture area lasts 52.65555 microseconds.

When that scan line is drawn, however wide it is, the 484 + 2 half lines of vertical distance should be 3/4 of that scan line width. That is the definition of the 4:3 display aspect ratio.

You can define any digital sample matrix you want, at any sample rate you want, but if the number of digital samples on a scan line (horizontal pixels) divided by the sample frequency is higher or lower than 52.65555, then you're oversampling or undersampling the active picture area, and your SAR and DAR must compensate.

Just saying "oh, 704x480 should be 10:11" isn't really enough information to determine if that's true. You need to know the sample frequency of how that digital sampling matrix was created. And if it was created at 13.5 MHz, that's wrong.

704x480 is a bastardized format that results when a 13.5 MHz sampling rate is used to resample an ITU.601 picture, which itself is wrong, because the ITU.601 picture is undersampled. (Proof: 640 horizontal pixels sampled at 12+3/11 MHz is a horizontal timing of 52.1841 microseconds, almost a full 1/2 microsecond short of the active picture area, which is over 6 pixels.)

The only page on the internet that accurately describes what is going on is that second link you posted, and that page is brutally correct in that the correct sample matrix for NTSC when sampled at 13.5 MHz is 710.85x486, with an SAR of 4320:4739. As this SAR is kind of impractical to use, and being accurate within 1 pixel should be completely undetectable, using 711x486 with an SAR of 72:79 is practical.

I don't mean to nit-pick, but the digital sampling must be tied back to the analog definition of NTSC to be meaningful, and the analog specs have to determine what is "correct". If the digital sampling method used cannot reconstruct an in-spec analog signal, then it's not correct in my book.

[ronnylov]

I wonder which profile and level should be used when encoding blu-ray compliant 720x576 video?
According to this: http://www.videohelp.com/hd#tech
AVC/H264 - MPEG-4 AVC: HP@4.1/4.0 and MP@4.1/4.0/3.2/3.1/3.0
Then I could use HP@4.0 for instance.

But here I got other info:
http://www.avsforum.com/avs-vb/showthread.php?t=972503
The associations responsible for the HD DVD and Blu-ray Disc standards approved the H.264 profile/level High@L4.1 for HD content, and High@L3.1 for SD content. As such, the Cyberlink decoder enforces compliance with the levels.
This tells me that Blu-ray disc standard approved High@L3.1 for SD content.
But this contradicts the info from videohelp where it say high profile only for level 4.1 and 4.

So what profiles and levels are blu-ray compliant for 720x576 material?
And as a side note, is dxva really limited to level 3.1 for SD?

[shon3i]

For 576 or 480 you can use HP or MP profile, and 3.0/3.1/3.2/4.0/4.1 levels, it's your decison. According level you have specific restrictions mosly for VBV.