ImgBurn + Verbatim Media = 2 channel from Surround?

[BassPig]

Super weird mystery... I didn't realize that burning to Verbatim BD-R changes the audio from Dolby surround 5.1 to Dolby Stereo 2 channel.

Let me back up a bit... Adobe Encore CS3 BD-R project. I made a surround sound disc of a concert I filmed in March 2010. The image is dated March 26, 2010. I burned a few BDs from that image over the past year. The first BDs were burned in Nero 8 and they play as M-ch (surround) on the BDP83. Last month, I burned a new BD copy from that same image, only difference was I used Verbatim media and ImgBurn to burn the BDMV and Certificate folders to the disc. That disc plays as 2-ch in the Oppo. I can pop in the older disc made 8 months ago and it plays as M-ch as full surround. The newly burned disc on Verbatim only plays through the front L+R speakers and the C, LS and RS are silent. The player shows 2-ch on the front panel when the Verbatim disc is playing.

Two discs burned from the SAME source image--one is surround, one is stereo. How is this even possible??

The good disc with m-ch audio reports as follows:

BD Disc Information:
Disc ID: SONY-NO1-002
Disc Type: BD-R
Disc Size: 120mm
Disc Class: 0
Disc Version: 1
Number of Layers: 1
Layer Type: Writable
DVD Layer Present: No
CD Layer Present: No
Channel Bit Length: 74.50nm (25GB Per Layer)
Push-Pull Polarity: Positive
Recorded Mark Polarity: HTL
BCA Present: Yes

The newer burn Verbatim disc has this report:

BD Disc Information:
Disc ID: VERBAT-IMe-000
Disc Type: BD-R
Disc Size: 120mm
Disc Class: 0
Disc Version: 1
Disc Time Stamp: 03/2010
Number of Layers: 1
Layer Type: Writable
DVD Layer Present: No
CD Layer Present: No
Channel Bit Length: 74.50nm (25GB Per Layer)
Push-Pull Polarity: Positive
Recorded Mark Polarity: HTL
BCA Present: Yes
Maximum Transfer Rate: Not Specified
First PAA of Data Zone: 131,072
Last PAA of Data Zone: 1,658,494


My last two BD titles are playing in 2 channel stereo, even though the project is a surround 5.1 channel source. The discs I burned in March 2011 are surround. A new copy I burned last month on Verbatim brand media are 2 channel stereo. I thought there was something wrong with the Oppo player, so I rolled back the firmware and did a factory reset. It continues to play all NEWLY BURNED BD-Rs as 2 channel stereo, even though they have only a 5 channel surround track on them. The player is somehow converting the 5 channel to 2 channel when it sees a Verbatim disc. Utterly inexplicable. The only BD-Rs that play in full surround are ones I made last spring. Anything burned on the newer media is playing as stereo only. Dolby digital 1/1 on the menu. No other track exists.

Wow.. two BD-Rs burned from the SAME image. One is stereo, the other is surround sound. Only difference is the brand of disc media. SAME SOURCE IMAGE!!! Oppo BDP-83 plays the no name brand disc as surround, but plays the Verbatim disc as stereo. The source image is the original March 26, 2011 image. It hasn't been modified, so it's got 5 channel audio in it. So either something about ImgBurn is collapsing surround to 2 tracks (how, I don't know), or the Oppo is unable to properly read Verbatim media and downsamples to 2 track audio. Two discs, same source image, one is some off brand cheap media and the other is Verbatim media. Two totally different audio detected!!

Can anyone explain this phenomenon? Is it ImgBurn or is it the Verbatim discs that are at fault?

[srfscenar]

Why dont you try to burn a verbatim disc with nero and a no name (same as the one that works) with imgburn and tell what happens.

[BassPig]

I'm burning a bunch of discs from various known to be 5 channel image files I have. The results are very odd.

Nero... burning the March 26, 2010 multichannel BD image (of which I have a good Sony brand disc that plays as multichannel) just burned on Verbatim media and the Oppo plays it as 2-channel. The source image is the same source that made the multichannel playable Sony brand disc.

Unfortunately, I am out of the Sony discs and only have Verbatim left.

Only one disc I burned tonight of a Dec 2010 concert loads up as multichannel in the Oppo 83. All the rest of the discs I burned in Nero today are loading up as 2-channel instead of multichannel and the center/surround speakers are silent. I used Headac3he to decode the ac3 file that was used to make the project, just to make sure that it contained 5 channels of audio and it does.

This is a real head-scratcher. I can find no scientific explanation as of yet.

[setarip_old]

Weird indeed!

Just curious - For ALL instances, have you had IMGBurn set to UDF 2.50 for "Revision" and "UDF" for "File System"?

[BassPig]

Well, the mystery deepens.. it seems that all projects that I produced in Adobe Encore since March 2011 have had their surround audio transcoded to stereo audio. I've been using tsMuxer to look at the stream files produced by Encore. Older projects have 5 channels, 512kbs, 16 bit. The newer projects have 192kbps 2 channel 16 bit audio.

The really weird thing is that Encore's settings are pretty straightforward: don't transcode to PCM, leave it Dolby digital. It always used to pass through the Dolby surround tracks unmodified. Now, after rebuilding 3 projects from scratch this evening, all of them are transcoding the 5 channel surround into 2 channel Dolby Digital. That never happened before. I can't find a way to stop it from happening now. Encore has lost its mind.

No one ever noticed the missing surround channels because most listening is done from the center front row in our screening room and the sound imaging of the audio system is so good that even with just the front L+R channels playing, it sounds like surround. So we never noticed the real surround was missing! That was, until this afternoon, when I was standing off to the side and noticed no sound coming out of the rear speakers. Looked at the Oppo display and it said '2.CH'.. hmmm.. WTF? So now we know. We thought we were making surround BDs for the past 7 months and we were in fact mislabeling our BDs as surround 5.0 when in fact Encore has been sneekily reencoding everything to 2.0 stereo for the past 7 months. This is infuriating. And I cannot seem to fix it. There's not much to Encore's project settings/advanced. It's all right where it should be. But Encore is no longer happy to pass the files through--it has to collapse them all to stereo now. Don't have a clue as to why. Any ideas?

[BassPig]

I think I'm done with Adobe Encore.
I need to find an alternative Blu-ray authoring environment that works.
Preferably, one that allows me to put 24/96 PCM 6 channel audio on the disc, because I really don't want the compromise of Dolby AC3, even at 512kbs.

Another thought is if it can be done easily enough, demux the m2ts streams after authoring, strip out the 2/0 Dolby and strip in 5/0 PCM and then remux it. Is that doable?

[setarip_old]

1) You haven't answered my question about IMGBurn settings

2) Sounds like you may be using a reduced ability version of Encore or your playback software (If I remember correctly, the OEM versions of Power DVD are limited to two channel output). Are these the same versions you used prior to March 2011?

[BassPig]

ImgBurn is set to UDF 2.5.


I have been using Encore CS3 since May of 2008. I have been successfully producing 5 channel audio BD-Rs from May 2008 to March 2011. The last 'good' disc was pressed on March 26, 2011. All authoring subsequent to that date are being recoded to 2 channel stereo for some unknown reason.

I fired up the other workstation this evening and trying copying all the source assets to the other workstation and building a new Encore project on that system, just to rule out any possible problem that may have happened --corruption of the software, etc-- by trying it on a separate workstation, also equipped with Encore CS3. It too, recoded my 5 channel AC3 down to a 2 ch ac3 file. The stream files are definately 192Kbps 2 ch 16 bit, according to tsMuxer.

The playback test setup is an Oppo BDP-83 Blu-ray player in our screening room. What's Power DVD? Is that an authoring system?

Encore has been nothing but fickle over the years, but we usually managed to get useful 5 channel BDs out of it. It never used to take so long building a disc before. Usually about 40 minutes. Now it's taking double that time, and the first 30 mins or so it is 'rebuilding audio tracks', so just what caused Encore to one day decide it doesn't want 5 channel ac3 anymore is the most confounding mystery.

The m2ts files are there in the STREAM folder, and if I could strip out the 2.0 ac3 and strip in either the 5.0 ac3 from the project assets, or strip in the original 5.0 PCM, that would at least enable me to keep working. Otherwise we're finished with Blu-ray until we can find an alternative authoring system that works.

[BassPig]

tsMuxer seems to offer much promise. I was able to demux the m2ts stream with Encore's defective audio and mux in the 5 channel ac3 from the original asset. The disc plays perfectly.

Now, I'm trying a bolder step: substituting a 5 ch PCM audio file. I've exceeded the disc space limit, but ImgBurn will let me burn to the end of disc and truncate. It's on a RE media so it's good enough to see if the PCM audio works. If it does, I can render a new video track at lower bitrate as needed to accomodate the extra 3GB that the PCM audio requires.

[Ghitulescu]

Maybe this was the reason Encore reencoded your audio ... to save space; audio reencoding is almost transparent on modern PCs, but video will still take some time and you'll notice this even without prior notice. Maybe there have been a warning before, or a setting ...

But what a strange idea you came across, that Verbatim conspired to ruin your work ....

[BassPig]

The reason I suspected the disc media or the Imgburn program is because the files on the hard drive were the ones I was sure were used to make the first disc that was multichannel audio and played as such. Apparently, the folder must not be the original revision of the disc.

At any rate, Encore is reencoding ALL projects now, whereas it used to respect my settings before.

In the meantime, I'm using this opportunity to see if I can free myself of the Dolby compression entirely, now that I can mux new audio tracks into the stream.

I was able to replace the 2ch Dolby with 5ch Dolby surround and make the disc image perfectly fine in tsMuxer. Burned and plays correctly on the Oppo player.

What I'm having trouble with is making a disc with PCM multichannel audio. The Oppo sees the audio track as "Dolby 1/1" instead of m.ch PCM. I've tried both 5 and 6 channel PCM file formats. tsMuxer happily assembles the stream, but the Oppo plays the video and outputs no audio whatsoever, while displaying that it's Dolby digital 1/1. The bitrates are moderate, according to the Oppo's "i" information menu, as the disc plays. I would have expected MUCH higher bitrates with the PCM audio over the Dolby. The stream file certainly got a LOT bigger.

I thought Blu-ray spec includes multichannel PCM. Am I wrong?