Bit Rate

rayrayjay wrote on 7/8/2019, 9:56 AM

Hey guys, I rarely post because with only one exception, I have always been able to find my answer on these boards.

My Bluray disc is freezing at the same point every time, or close to it.

I used Vegas to render a project in AVC, I set the max bit rate at 40mbps, the average at something like 30. ( I did this after I was originally setting it EVEN HIGHER, but figured since DVD Architect could only max out at 40, anything after that was lossy.)

Then I set the bit rate on DVD architect to the same specs-still freezes at same spot

Then I used better quality blank discs-Still freezes at same spot.

Then I lowered the bit rate on DVDA to 35 mbps-Freezes at same spot.

Then I lowered it to 30mbps, and the freeze happens later in the film.

2 questions. What is happening? Can this be fixed? And two, if I lower the bit rate to 25mbps, would I be better off at 40mbps in MPEG2. Because MPEG2 works at 40mbps, but its a noticable step down in quality. Is MPEG2 at 40mbps > , = , < AVC at 25mbps?

Just thought of this? Could it be the layer flip? I am using the 50GB blurays, and when I lowered it to 30Mbps, the software tells you about how much of the disc you are using, and using that as a reference, they "sorta coincide?" I guess?

Comments

Former user wrote on 7/8/2019, 2:09 PM

How long does the freeze last? It could be the layer change which is dependent upon the player. My bluray player is very smooth over layer changes. I guess it buffers. 40mbps is too high for a Bluray. You should max around 35mbps, but if your freeze moved when lowered bitrate, especially since it became later, that sounds like the layer change. Try it on a different player.

rayrayjay wrote on 7/8/2019, 7:32 PM

I have tried it on a Sony Player and a PS4. Same spot both times. The freeze time is about 90 seconds.

rayrayjay wrote on 7/8/2019, 7:47 PM

I'm really upset-disappointed. I have been working on this particular problem every weekend for a couple months. Finished my edited product, MONTHS ago. I now have the bit rate set at 25mbps on DVDA, and I have now moved the freeze spot back even further. It lasts about 2 minutes and when its finished, it jumps to the end of the film...about 12 minutes further. I'm getting sold on the layer flip possibility. But if thats the case why dosent the layer flip problem occur when I use mpeg2 and get all the way up to like 42 of 50 GB? And what do I do about it?

Former user wrote on 7/8/2019, 8:27 PM

90 seconds is a long time. That does not sound like a layer flip, unless your burned disk is not right. Could be a bad burner or bad quality disks. I don't burn dual layer because they are iffy.

nepomuk wrote on 7/9/2019, 3:51 AM

….... 40mbps is too high for a Bluray. You should max around 35mbps, …..

Why? 40Mbps for video is fully Blu-ray compliant, level 4.1.

But it appears indeed that DVDA does not accept the 40Mbps (my own experience). In another thread/post it was mentioned that one should go just slightly below the 40, say 39.999 in order to satisfy DVDA …..

Teagan wrote on 8/11/2019, 2:09 PM

The max bitrate for burned blu rays with AVC is around 20Mb/s. "Pressed" blu rays can go up to around 40Mb/s but that's because they're not burned - the process of making the tiny pits is much easier and more reliable with high bit rate when they are pressed professionally. If you go higher than 20Mb/s on a burned blu ray, you will encounter errors with blu ray readers.

This information is hard to find on the internet but that's how it is.

RedRob-CandlelightProdctns wrote on 10/10/2019, 11:19 PM

On that last post -- you're refering to AVC burns, not MPEG-2, correct?

EricLNZ wrote on 10/12/2019, 5:35 PM

On that last post -- you're refering to AVC burns, not MPEG-2, correct?

I assume it will apply to whatever is on the disc. It's a question of the laser being able to read the bits at the necessary speed. Only when it's read the bits does it know how to handle them i.e. which codec to use.

My understanding is that with HD AVC is preferable to mpeg-2. The latter was designed back in SD days whereas AVC is a more modern efficient codec and will give the same quality at a lower bitrate compared to mpeg-2.

rayrayjay wrote on 10/13/2019, 10:33 AM

Man I just had to give up on it. AVC that goes over 25GB just craps out on all players, right at the layer flip. I can either burn up to 50GB MP-2, or up to 25GB AVC. Life sucks.

rayrayjay wrote on 6/9/2020, 2:16 PM

I thought I would check back on this. My goodness, I was quite winey. Sorry. I still have no answer. I came to peace with only being able to burn single layer blurays. But I wish I could do dual layer. Hoping someone finds an answer.

rayrayjay wrote on 3/1/2022, 4:03 PM

Hey all, please help if you can, I am revisiting this issue. Its 100% a problem at the layer flip. Always when I use AVC encoding. I DID update the driver in my bluray burner. After doing that the issue has changed. It still breaks at the layer flip, but now it just becomes super compressed. As soon as the layer flip happens there is no break on screen or sound, but the screen becomes almost unwatchable due to compression.

rayrayjay wrote on 3/1/2022, 4:05 PM

The max bitrate for burned blu rays with AVC is around 20Mb/s. "Pressed" blu rays can go up to around 40Mb/s but that's because they're not burned - the process of making the tiny pits is much easier and more reliable with high bit rate when they are pressed professionally. If you go higher than 20Mb/s on a burned blu ray, you will encounter errors with blu ray readers.

This information is hard to find on the internet but that's how it is.

Has this changed? Its been a few years?

EricLNZ wrote on 3/1/2022, 4:39 PM

Has this changed? Its been a few years?

Not to my knowledge. Stick to AVC at 20Mb/s is the usual recommendation. Do you really see better quality if you try to go higher?

With disc burning on the way out the availability and quality of discs is probably a bigger worry. So few manufacturers are producing them now.

rayrayjay wrote on 3/2/2022, 8:13 AM

Has this changed? Its been a few years?

Not to my knowledge. Stick to AVC at 20Mb/s is the usual recommendation. Do you really see better quality if you try to go higher?

With disc burning on the way out the availability and quality of discs is probably a bigger worry. So few manufacturers are producing them now.

Well, I hear ya, and to answer your question for my project, technically yes. I have a 4k projector, and have a subtle eye for it, and the original content that I'm editing was a higher bitrate, professionally pressed. Having said that, would you agree that a good test would be having a large enough project so that I get to my second layer at 20Mbps and still see a second layer issue? Or would you tweak some part of that test?

rayrayjay wrote on 3/6/2022, 9:17 AM

Has this changed? Its been a few years?

Not to my knowledge. Stick to AVC at 20Mb/s is the usual recommendation. Do you really see better quality if you try to go higher?

With disc burning on the way out the availability and quality of discs is probably a bigger worry. So few manufacturers are producing them now.

Ok, first, thanks Eric for talking to me about this. I have fought this "on again, off again" for years now. I can now narrow it down even more. Its not the bit rate. I found a way to get DVDA to burn at 40 mbps in AVC dual layer! Keep in mind it always did the first layer fine. The difference was not in the AVC codec. It was in the source material for DVDA to read. I tried using MPEG -2 to render out of Vegas. I went with the 80MBPS which appears to be the max, and is "about" equal to AVC at 40MBPS. Then DVDA was able to burn both layers in AVC at 40 with no issues that I could tell. I didnt love compressing it twice with two different formats but at that high of a rate I cant tell that it suffered much. So what I planed to tell support is that DVDA cannot burn in AVC in dual layer from an imported format such as mp4 from AVC. The 40Mbps is not the problem, I can drop that to 20Mbps and have the same issue if I have long enough source material to hit the second layer. (If I upload it via .mp4/AVC from Vegas)