Max bitrate for most dvd-players?

riredale wrote on 12/15/2012, 7:46 PM

As for a disk not playing at the very end, I wonder if it's a burner or authoring issue? I use DVDlabPro for the authoring and Nero for burning, and have never seen this. My projects end with a 4-second black before going back to the menu or player screen. Never an issue.

I do think that cheaper DVD blanks have worse quality control, and sometimes that manifests itself with more warp, such that the player lens assembly can't keep up with the focus. For example, when burnable DVDs first came out I was a fan of putting full-face labels on my disks. Worked fine--for a couple of years. Then I would get reports of disks playing fine until hanging halfway through. When I took the disk back and ran it through Nero DVD Speed, sure enough, few errors at the beginning, then an unbelievable number starting about halfway. But if I removed the label (using WD-40; amazingly, no ill effect on the disk afterwards) then it played fine to the end and Nero confirmed that correctable errors rose gradually (as they always do with any disk) but uncorrectables were still very low. So I would attribute the label experience to a very slight warping of the disk as the adhesive aged.

By the way the Nero tool mentioned above can also check for optimum burning speed. Burn a disk at maximum rating, then try one a bit slower. With premium media I hardly see a difference in error rates.

VBR make absolutely no sense--until one needs to put more than about 75 minutes of material on a DVD-5 blank. At that point your CBR rate has to drop from 8Mbp/s, and in areas of fast motion and/or great detail you might start to see artifacts. Then VBR is your friend, allowing those demanding portions of the disk to still use 8+Mb/s while lowering the bitrate for video not needing it.

As for Hollywood, I think with the gorgeous noise-free source footage, the 24fps frame rate, and the expensive MPEG2 encoders they use, they probably don't see much benefit going to a higher bitrate. But our video output is a whole different situation. And as for the DVD player smoking, I'd suggest it was broken and took that unfortunate time you were using it to manifest that fact. Not trying to dispute your experience, but every DVD player by definition must meet the DVD specs, and that calls for playback of up to 9.8Mb/s for video + audio.

HOWEVER, Wikipedia says this:

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"DVD-Video discs have a raw bitrate of 11.08 Mbit/s, with a 1.0 Mbit/s overhead, leaving a payload bitrate of 10.08 Mbit/s. Of this, up to 3.36 Mbit/s can be used for subtitles and a maximum of 9.80 Mbit/s can be split amongst audio and video. In the case of multiple angles the data is stored interleaved, and so there's a bitrate penalty leading to a max bitrate of 8 Mbit/s per angle to compensate for additional seek time. This limit is not cumulative, so each additional angle can still have up to 8 Mbit/s of bitrate available.

Professionally encoded videos average a bitrate of 4-5 Mbit/s with a maximum of 7–8 Mbit/s in high-action scenes. This is typically done to allow greater compatibility amongst players, and to help prevent buffer underruns in the case of dirty or scratched discs..."

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So maybe where a lower average bitrate helps the most is that a disk can be more warped, scratched, or dirty and still play on a tired player with a dusty laser lens without skips.

Finally, at risk of beating this poor horse to death, I do recall that back when I used Ritek DVD-R blanks many years ago, I would often see greatly-increased read failures on the outer portion of a disk using the Nero utility after the burned disk had aged for a couple of years. Then I read that Ritek is regarded as a second-tier blank, not in the same category as "premium" blanks such as TY or Verbatim. So it pays to use the best.

musicvid10 wrote on 12/16/2012, 12:18 AM

"VBR make absolutely no sense--until one needs to put more than about 75 minutes of material on a DVD-5 blank."

With 8Mbps CBR, what you take off the bottom you also take off the top. So while 2Mbps may be all that is necessary to prevent artifacts in relatively static scenes, you are also eliminating the 1.5Mbps overhead for transient, high-motion, high-detail scenes that would actually benefit from 9.5Mbps. By saying that it makes no sense unless one needs more room, is another way of saying CBR is just inefficient.

I know I have friends here who will (and have) disagreed, but having 9.5Mbps available in reserve, and not wasting space unnecessarily when such a high bitrate is not needed, is a big advantage when that space could be better put to use with uncompressed audio, for instance.

"Professionally encoded videos average a bitrate of 4-5 Mbit/s with a maximum of 7–8 Mbit/s in high-action scenes."
That's actually a bit low by comparing releases in the past five years. 6Mbps ABR is pretty much the norm.

Grazie wrote on 12/16/2012, 1:00 AM

This should be writ LARGE somewhere . . I don't know where, but it says everything I and others need to keep "live":

"With 8Mbps CBR, what you take off the bottom you also take off the top. So while 2Mbps may be all that is necessary to prevent artifacts in relatively static scenes, you are also eliminating the 1.5Mbps overhead for transient, high-motion, high-detail scenes that would actually benefit from 9.5Mbps. By saying that it makes no sense unless one needs more room, is another way of saying CBR is just inefficient."

Musicvid - THANK YOU!

Grazie

farss wrote on 12/16/2012, 3:54 AM

"I do think that cheaper DVD blanks have worse quality control"

The problem is with the "stamper". These dies are quite expensive, probably the largest cost component in manufacting the disk. It's the outer edge that wears first. I was told years ago there was even a black market in 2nd hand stampers. Buy cheap enough media and you could really be getting a product made from John West's rejects. Of course the crooks can largely get away with this because most consummers don't fill the disk anyway.

I've only once had a major playability problem, almost everyone had their player stall at the same place. Problem was traced to a huge change in bitrate at the point. If using VBR keep the minimum bitrate higher than a quarter of the maximum.

A small percentage of complaints is to be expected. Burnt media has a lower reflectivity than pressed so, as the player's laser wears out, the first symptom is it has issues playing burnt media. Alarmingly I've found cheap players seem to wear out just sitting there. I gave up buying cheap units, I really don't like creating more landfill than need be.

As for two pass compared to one pass VBR. I too use 2 pass when pushing the bitrate down however I'm not convinced it really makes much difference. The averaging window seems very short. This might explain why the best encoders can do way more passes to get the optimal fit.

One last tip. Lower burn speeds may not give a lower error burn, in fact a lot of media today cannot be burnt at 1X. For DVD 8X seems the best and for CDA 20X. The explaination is the faster spinning disk has less wobble. Make of that what you will but the supplier who gave me this tip had the gear to actually test this.

Bob.

Grazie wrote on 12/16/2012, 4:14 AM

@Bob The explaination is the faster spinning disk has less wobble.

Stunning! Where on Earth do you glean these nuggets? Fab.

I recently pushed a DVD's output through BitRateViewer, and there it was. A huge spike on the area I was getting pixies. I'd used the Burn-To-Disc quickly. Went back to my Grazie-Templates and picked the tried and tested - Job done.

Grazie

Former user wrote on 12/16/2012, 7:18 AM

I am one of those fixed bitrate advocates. I have never had a DVD rejected at 8Mbps with AC3 audio. If I am using PCM, I wiil go a little lower. I very seldom go below 6 unless the client is insistant that their over 90 minutes video fit on a single sided disk.

I use a very old (relatively speaking) Pioneer DVD player as well as a Panasonic combo VCR/DVD player to test my personal DVDs and a new Sony Bluray and an older forgotten brand DVD player at work, and both work fine with CBR at 8Mbps.

When using CBR, I never notice the flickering at fades from and to black and I do see with VBR.

My Pioneer player shows the current playback bitrate and I notice that varies when even playing a CBR disk. Since I normally use a 192 or 256kbps AC3, I don't know where the variance comes from, but I would guess it is that even at CBR, it is not truly playing back at a constant rate. And with CBR I have seen the bitrate jump as high as 10Mbps.

We do use DVD recorders at work as well, and are not able to use the Higher bitrate encoding on these recorders. When we first got them, we did and were getting several rejected burned DVDs because the players could not handle the high rates. I noticed these would constantly peak at 9.5Mbps. We now record on the Medium speed when I believe runs around 4-6Mbps.

Another thing in reference to commercial bitrates. In a professionally done commercial movie situation, the MPEG encoders allow for customized bitrates in specific areas of a movie or video. Thus if an action scene shows more artifacts than the encoder wants, he can adjust the VBR for that specific area to minimize these. Same with fades to black or other areas where the enocder might misinterpret the required bitrate. Fades are usually where I notice the most artifiacting in VBR files.

So I respect Musicvid and his superior technical knowledge in these areas, but I also disagree. But of course, he already knew that. :)

Dave T2

musicvid10 wrote on 12/16/2012, 8:17 AM

Dave, much of what I learned came from you, when I was but an erstwhile VHS editor "before the turn of the century." So any superlatives you may kindly reserve for yourself, OK?

(Dave and I both defected from the Pinnacle Studio forums when Vegas 2 was in its heyday.)

musicvid10 wrote on 12/16/2012, 8:35 AM

"Another thing in reference to commercial bitrates. In a professionally done commercial movie situation, the MPEG encoders allow for customized bitrates in specific areas of a movie or video."

The beauty of x264 is that it does this for you. "Constant Quality" mode is fast single-pass encoding (up to 4x faster than 2-pass vbr with Mainconcept), however the file sizes are unpredictable, based on temporal quality (you can cap the maximum bitrate though).

For HD it is a treat (as much as 30-50% off file sizes), but not so much for analog source, where CQ can try too hard to preserve the "quality" of resident film grain and noise, making files too large without preemptive controls.

riredale wrote on 12/17/2012, 12:40 AM

Wow, you guys were over at Pinnacle Studio also? I suspect a lot of us were. I went by "riredale" over there, too, I think. On the forum one day someone (maybe one of you guys?) mentioned that the Sonic Foundry guys had a cool demo showing how their DV codec could make numerous cycles without losing much image quality. I went over to investigate and switched shortly thereafter to Vegas 3, around the spring of 2002.

Back on topic, the CinemaCraft encoder is a wonderful toy to play with. You can specify one pass VBR, two pass VBR (to meet a bitrate target), and a constant Q setting too.

And CCE also allows one to dig into the finished MPEG2 file and manually change the bitrate over a portion of the timeline to, say, eliminate a glitch of blockiness that the encoder somehow missed. When I was doing some ultra-low-bitrate projects nine years ago I used that feature a number of times, and it worked great. But the Vegas MainConcept encoder has gotten closer to CCE's quality over the years, and now it's just easier to use it instead for most stuff.