Blu-Ray Compression/Disc Size

[koberulz]

I've burned a lot of basketball games to DVD in the past, and I have a pretty good handle on what looks good: I'm generally happy with an hour and a half to an hour and forty minutes on a single-layer disc, beyond which I move to dual-layer.

And of course everything is MPEG2.

With Blu-Rays, I have no idea where to start. There appear to be two available codecs: MPEG2 and H264. And Blu-Rays in general seem to be able to hold more footage. So in order to get the best quality, what should I be doing? Which codec should I use? At what point does a dual-layer disc become worth it?

I know it's largely subjective and whatnot, but some sort of ballpark idea of what to expect would be appreciated. There's no point going out and getting DL discs to experiment with if 2-2.5 hours will fit on a single layer with no issue, for example.

And from what I can find, it seems I don't need an explicitly DL burner to burn DL Blu-Ray (it plays DL discs fine)?

[DB83]

The rules with blu ray are the same as with dvd.

Blu ray requires higher bitrates for the larger frame size and higher quality audio. So you just do the maths and calculate the size of the encodes.

[koberulz]

Sure, but I'm curious as to what the quality will look like if I try to get, say, 2.5 hours of 1080i footage onto a single-layer disc. Is that something I'd still get good quality out of, or would I need to go dual-layer? And how does codec affect this? A quick Google shows that H264 will generally produce higher quality at the same filesize as MPEG2, so that would presumably allow more footage to be squeezed onto a disc.

[LMotlow]

You can encode standard definition video using BluRay or AVCHD as MPEG or h264. Not all BluRay's are "HD". You'd have a problem, though, burning straight "DVD" to BluRay disc -- some players might not make nice with DVD on BluRay. From what I've heard, BluRay DL isn't all that stable.
The general BluRay specs are here: https://www.videohelp.com/hd#tech
The nitty-gritty nit-pickey on BluRay for MPEG and h264 are here: http://forum.doom9.org/showthread.php?t=154533 , but most BluRay encoders should set this up properly for you.

I prefer MPEG myself, it doesn't look as "filtered" as h264 and seems to handle interlace better. But that's IMO.

If you're thinking of upscaling SD video to 1920x1080, it's usually not worth the trouble. The advantage of SD-BluRay is the use of higher bitrates. SD upscaled to HD doesn't look as cool as you think it will, because SD isn't HD to begin with. The difference is "resolution", not frame size.

1080p progressive at 29.97 or 25 fps isn't allowed for BluRay. At those frame rates, BluRay "1080" is interlaced. At 1080 you can encode progressive video for film speeds 24 or 23.97 fps progressive. If you really wanna go through the trouble of upscaling interlaced 16:9 SD to HD, try double frame rate 1280x720p, 60fps (NTSC) or 50fps (PAL). Those frame sizes are 16x9 only. You can get HD with 4:3 video as 1440x1080, interlaced. SD blown up to HD looks blurry, like a small negative blown up to poster size.

[DB83]

But if you are 'curious' you must simply create a disk. 'Quality' by your definition is 'how it looks' so only you can be the judge.

[koberulz]

standard definition video

I'm working from a 1080i 25fps source.

But if you are 'curious' you must simply create a disk. 'Quality' by your definition is 'how it looks' so only you can be the judge.

I did acknowledge this in the OP. I'm really not after hard-and-fast rules, just a ballpark idea of how long a basketball game I could fit on a BD25. Basically, at present my experiment range is 0mbps to 40mbps (I think, I may be wrong on the exact numbers). I'd like to narrow it down a bit.

EDIT: Additional question: does a Blu-Ray layer break have the same pause as a DVD layer break?

[LMotlow]

You talked a lot about all the DVDs you've been making. All you said about 1080i was that you were "wondering" about it. Anyway, you can can edit. author and burn 1080i HD to BluRay disc. A basic target bitrate of 15 or 20MBps VBR should be good enough for action video. Sometimes you just have to try it to find out, but action video requires more bitrate than a museum documentary where hardly anything moves.

If what you really meant in your posts was that you're shooting 1080i AVCHD and burning them to DVD disc, you should have said so. Get a BluRay authoring program and see what happens. However, if your 1080i AVCHD is playing at 1080i and 16x9, a BluRay will play the same way.

[koberulz]

Previously, I've been working with primarily SD sources, downscaling anything that isn't and burning DVDs. Now, I'm going to be working with primarily HD sources, and would like to try burning them to Blu-Ray.

A basic target bitrate of 15 or 20MBps VBR should be good enough for action video.

This is the sort of answer I was after, thanks. That's about two hours forty minutes on a BD25, yeah? That should be plenty.

[PuzZLeR]

A basic target bitrate of 15 or 20MBps VBR should be good enough for action video.

This is the sort of answer I was after, thanks.

A good approximation, yeah. But an even better one, which is near-perfect in accuracy, is delivered when you use quality based encoding.

[koberulz]

"Quality based encoding"?

[PuzZLeR]

"Quality based encoding"?

This is a method several encoders (MPEG-2, H.264, DivX, Xvid, etc) use to give you the quality regardless of bitrate. It uses theories from signal processing in physics.

You select a quality level at the start, then, in one pass the encoder will provide the minimum bitrate, frame-per-frame, to give you that quality. It will apply more bitrate to scenes that need it most, typically high-motion scenes (expect many such scenes in basketball games), but it will apply less bitrate to scenes that will not need it much (like maybe in an interview scene).

You may end up with a higher bitrate than you want, or you may be pleasantly surprised. In the end, you can count on a result that gives you consistent quality throughout and takes the guesswork out of it. Personally, I live by it, and has been one of the best things for me in this hobby.

An encoder that doesn't support quality based encoding is useless IMO.

However, I'm a bit confused as to what you are doing. Are you encoding your result, or using the source direct? If your source is 1080, then you must be encoding to get it to DvD. If your source works on the desired media as-is, keep in mind encoding to a lossy format like MPEG-2/H.264, no matter how good the method is, will degrade the quality and increase your workflow times.

[koberulz]

So "quality based encoding" is another way of saying "variable bitrate"? Or is there something I've missed? I do use 2-pass VBR for my DVDs, unless I'm working with between 1:40 and 2:00 of footage or so, in which case a CBR at the maximum DVD-compliant bitrate gets the job done quickly at the highest quality while still fitting on the disc (less than 1:40 and I usually use a DVD5). And I'd go the same way for BD, but in order to make it fit on a disc I still need a target bitrate, which according to LMotlow will be in the 15-20 Mbps range.

The source footage needs editing, so I have to encode to achieve that. Plus making it compliant with either DVD or BD, depending on what I'm doing.

[PuzZLeR]

So "quality based encoding" is another way of saying "variable bitrate"? Or is there something I've missed? I do use 2-pass VBR for my DVDs, unless I'm working with between 1:40 and 2:00 of footage or so, in which case a CBR at the maximum DVD-compliant bitrate gets the job done quickly at the highest quality while still fitting on the disc (less than 1:40 and I usually use a DVD5). And I'd go the same way for BD, but in order to make it fit on a disc I still need a target bitrate, which according to LMotlow will be in the 15-20 Mbps range.

Nope. Quality based encoding does indeed rely on variable bitrate, but it is not VBR. And it works in one pass, but it's not CBR.

I meant something completely different, or rather, the opposite. You're describing a method in which you choose the bitrate at the start and the method produces a result that could vary in quality. I'm proposing a method that chooses a quality at the start and produces a result that could vary in bitrate.

All video is different. Even two basketball games could need different bitrates for the same quality. It's very hard to determine this beforehand and there are way too many variables. However, quality based encoding gives you the answer.

2-pass methods, or bitrate methods, are a thing of the past really, and only for the "fit-it-on-a-disc" mentality, which may be what you're trying to do, but it's not the most optimal for quality.

And when you're using CBR, you are likely using more bitrate for the quality you need. Quality based encoding will give you a similar quality at less bitrate if you know what you're doing.

What encoder(s) are you using?

The source footage needs editing, so I have to encode to achieve that. Plus making it compliant with either DVD or BD, depending on what I'm doing.

You may not need to encode to edit depending on video format/editor, but if it's not DvD/BD compliant, yes, you need to encode.

What exactly is your source format/video type?

[koberulz]

What encoder(s) are you using?

Adobe Media Encoder.

What exactly is your source format/video type?

It varies. For the Blu-Ray projects, it'll be 1080i M2TS files. I've also used 720p and 576i MP4 files. Possibly others.

And when you're using CBR, you are likely using more bitrate for the quality you need. Quality based encoding will give you a similar quality at less bitrate if you know what you're doing.

It doesn't really matter to me whether a DVD9 is 90% full or 95% full, though.

And given that the end result needs to fit on a disc of a specific size, encoding in a way designed to fit on a disc of a specific size seems sensible.

[PuzZLeR]

What encoder(s) are you using?

Adobe Media Encoder.

I've never used it myself, but just looked at a tutorial. Where it says "Bitrate Encoding" where you can select, for example, "VBR 1 Pass", can you tell me what other options are there? Are they all bitrate based?

What exactly is your source format/video type?

It varies. For the Blu-Ray projects, it'll be 1080i M2TS files. I've also used 720p and 576i MP4 files. Possibly others.

Depends what's in the M2TS files, and depends how they're captured. For example, if they have H.264 streams in them, and they are blu-ray compatible as-is, or have MPEG-2 streams in them, a re-encode may not be necessary for blu-ray and/or DvD. You will only need to do the edits with an editor that is capable of the format.

And when you're using CBR, you are likely using more bitrate for the quality you need. Quality based encoding will give you a similar quality at less bitrate if you know what you're doing.

It doesn't really matter to me whether a DVD9 is 90% full or 95% full, though.

And given that the end result needs to fit on a disc of a specific size, encoding in a way designed to fit on a disc of a specific size seems sensible.

Sure, exactly.

But my point is that it doesn't answer the fundamental question to your thread here. You wanted to know what, to the effect of, what size for what quality for a given codec/format (MPEG-2 or H.264). The only correct answer you will get is with the result given by quality based encoding. Everything else is just speculation or estimation when at the human perception level, even after some experience.

One can say that there are "about" 2 stars in our galaxy. It's an estimation alright, but its accuracy is still in question without better methods. When you were told 15-20 mb is a good target, I say it's not a bad estimation, but it certainly isn't the precision-accurate one either, and certainly may not apply to all video or games. And I'm also saying that you will never know the true answer without quality based encoding.

As well, if you employ quality based encoding, you may find you actually need more discs, or DL (less content/disc space), or contrary - less discs (more content/disc space), to get the quality you want. Only quality based encoding will give you your true answer. That was my point.

I don't know about Adobe's encoder, but x264 and HC Enc (free apps) have quality based encoding for H.264 and MPEG-2 respectively.

[koberulz]

Sure, but my plan isn't "take 15-20 Mb and run with it", it's "use 15-20 Mb as a starting point, and experiment from there". Basically, it maximises the chances my first disc will be usable, and then I can fiddle with it over the course of the season. Rather than being in a position where I have to re-burn.

The only options in AME are CBR, 1-pass VBR and 2-pass VBR.

[PuzZLeR]

The only options in AME are CBR, 1-pass VBR and 2-pass VBR.

Too bad. You may be missing out on a good lesson in video here. Quality based encoding is a philosophy IMO.

Sure, but my plan isn't "take 15-20 Mb and run with it", it's "use 15-20 Mb as a starting point, and experiment from there".

Certainly. Sticking with one bitrate can "fit" somewhere, but is not the end-all for quality. Glad you understand this.

If you want to stick with a benchmark and experiment, using 15-20 mb is fine as a starting point, and shouldn't lead you out to sea if only dealing with one type of video (ex: only basketball games).

But I will recommend you at least try quality based encoding, such as with a different encoder, if you want to be more picky, and test it on different sources. Even if you still want to stick with AME in the end, that's fine, at least another encoder may give you more insight on different sources - even if it's two basketball games. You may be surprised what you'll get. Just a suggestion.