Odd issue with Charade (BD Rebuilder)

[woecarlson]

Hi all,

I used BD Rebuilder to shrink Charade down to fit on a BD-25, but the final product was still slightly too large. Never seen this one happen before with any other titles, and according to the log file it "should" have been targeting a small enough size. (Oh, the final output of the rebuilt Charade was 24.1 GB)

Any ideas why it did this and suggestions on a workaround?

[04:49:40] PROCESSING BATCH FILE [2]
-----------------------
[04:49:40] BD Rebuilder v0.38.09 (beta)
- Source: CHARADE_-_R
- Input BD size: 33.18 GB
- Approximate total content: [01:53:36.390]
- Target BD size: 22.95 GB
- Windows Version: 6.1 [7600]
- Auto Quality: Good (Very Fast), ABR
- Audio Settings: AC3=0 DTS=0 HD=1 Kbs=640
[04:49:41] PHASE ONE, Encoding
- [04:49:41] Extracting A/V streams [VID_00000]
- [05:34:42] Reencoding: VID_00000 (1 of 1)
- [05:34:42] Collecting video information
- Source Video: MPEG-4 (AVC), 1920x1080
- Rate/Length: 23.976fps, 163,430 frames
- Bitrate: 24,323 Kbs
- [05:34:42] Reencoding: VID_00000, Pass 1 of 1
- [08:55:09] Video Encode complete
- [08:55:09] Reencoding audio tracks (if req'd)
- [08:55:09] Multiplexing M2TS
[09:29:57]PHASE ONE complete
[09:29:57]PHASE TWO - Rebuild Started
- [09:29:57] Rebuilding BD file Structure
[09:29:57] - Encode and Rebuild complete
- WORKFILES folder removed.
[09:29:58]JOB: CHARADE_-_R finished.

[RobertM]

Hi Woe,

Since you are doing a 1-pass re-encode the final size will be a bit approximate. You might try a 2-pass, where the first pass will allow a better calculation of the final size.

Or, instead of picking BD-25 just use a custom size, and make it small enough so that the resulting rebuild fits onto a BD-25 disc.

[woecarlson]

Thanks RobertM! Where do I set the option for 2-pass vs 1-pass? Also, I see the option to use a Custom Size (with 23500 as the default), but since the target size of the original encode was 22.95 "shouldn't" that have been small enough?

[hoju3508]

Under Settings -> Encoder Settings; untick One Pass (ABR) Encoding.

[RobertM]

Where do I set the option for 2-pass vs 1-pass?

There are 3 choices: One pass (CRF), One Pass (ABR), or neither (which is 2-pass). As hoju3508 suggested, if you un-tick both one-pass selections then you will be in 2-pass mode.

since the target size of the original encode was 22.95 "shouldn't" that have been small enough

Not necessarily. The target value is only a target. The actual result will be NEAR the target, but might be a little higher or lower depending on the content material that needs to be re-encoded.

Perhaps knock off 0.5GB (from the previous target of 22.95GB) and see what you get... so use a "custom size" of about 22.5GB. It would be reasonable to presume that your resulting file will be about 0.5GB smaller than your previous result, so around 23.6GB, and that should fit.

[picrade]

Hi all,

I used BD Rebuilder to shrink Charade down to fit on a BD-25, but the final product was still slightly too large. Never seen this one happen before with any other titles, and according to the log file it "should" have been targeting a small enough size. (Oh, the final output of the rebuilt Charade was 24.1 GB)

Any ideas why it did this and suggestions on a workaround?



This may not have anything to do with 1 or 2 pass encoding.
The difference between the target size and the BD-RB re-encoded BD size is too great (> 1 GB) to account for that.

Is this Charade by Criterion? Does it have LPCM mono audio?
If yes, then the explanation is this:
LPCM mono audio takes twice as much space when muxed in a m2ts stream than it does as a demuxed wav file.
I mentioned this in the BD-Rebuilder bug report thread.

BD-RB demuxes the LPCM audio into a wav file and it is, say, 1 GB in size.
BD-RB re-encodes the video using the target size and the size of this wav file.
But at the end after muxing the audio and video into the m2ts stream the audio takes twice as much space.
Don't ask me why as I don't know the technical details.

I have seen this with all the Criterion releases that I have backed up which had LPCM mono audios.
Other titles: The Third Man, Stagecoach.

What I do in these cases is that before re-encoding with BD-RB I demux the LPCM mono track into a wav file.
Then I reduce the target size that I normally use by the size of the wav file and then re-encode.

[setarip_old]

But at the end after muxing the audio and video into the m2ts stream the audio takes twice as much space.
Don't ask me why as I don't know the technical details.

I have seen this with all the Criterion releases that I have backed up which had LPCM mono audios.Sounds like it's being converted from mono to 2 channel stereo somwhere in the process...