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Laserdisc PCM Capture Guide
#41
Success!

1. Follow Bronan's guide in the first post of this thread to setup your soundcard and Reaper.
2. Setup AmaracTV/Virtualdub to capture both video and audio (through the analog input on the capture card) - even though in the case of DTS that audio can't be decoded, it will come in handy when syncing as you'll see later.
3. Hit Record on AmarecTV, Reaper and then play on the laserdisc player. My player automatically flips the disc so I just let it all run for the entire film, and even if you have to flip the disc yourself it's probably easier just to let it run while you do this than have to restart it all at each side change.
4. When the disc stops at the very end of the movie, stop everything recording and render the reaper audio as described in Bronan's guide.

DTS audio will look a lot like this:

[Image: fDE3S3T.png]

Basically just two rectangles of sound, with space at the beginning while your player was spinning up, space in the middle for the side change and space at the end where you were fumbling with all the stop buttons. If you play it, it just sounds like digital noise.

5. IVTC the picture using Virtualdub or AVISynth as you normally would, but leave the side change alone at this point. Save the IVTC'd video including the captured analog audio stream as a prores LT Quicktime file.
6. Bring the IVTC'd video (and audio) just created, and the bitperfect wav file into Premiere Pro (I used 2018, not sure if earlier versions have the nice "Synchronize" option I'm about to use, though 2017 might have it) and create a new sequence. Because of the delay in clicking record, the audio won't line up right away:

[Image: xNPkqql.png]

This is why I recorded sound with the picture: it makes it easier to sync up the bitperfect stream. You can change the timeline measurement to "audio units" by right clicking on it. This will allow you to drag the bitperfect stream left and right a millisecond at a time until it lines up. OR you can just select all three tracks in the timeline, right click and choose "synchronize"

[Image: T7fgd4s.png]

Which is what I did. If you are just using regular digital audio captured this exact same way, you may find that even if you perfectly align the beginning of both audio tracks manually, they still drift a little out of sync. Using the automatic "synchronize" feature will resolve this problem.

After the tracks are sync'd, edit out the side change in the middle. You'll notice that the DTS audio continues right to the point where the disc spins down, even though there may have been a couple of seconds of black frames. Don't worry about trimming that audio too, it's just silence encoded as DTS so you won't miss it.

7. Mute the analog audio and then export the bitperfect stream as a wav file (16 bit, Stereo @44,100).
8. Export the Video - I used the Tmpgenc h264 plugin for Premiere, but you can use whatever codecs you want here. If your laserdisc isn't DTS and you just wanted perfectly sync'd bitperfect audio, then you're there already. No need to read on. But for DTS, there's still more to do.
9 While the video is rendering, it's time to sort out the DTS audio. There are still a couple of Gotcha's with DTS. The first thing you need to know is that when you run your DTSWAV through DTS Parser, it will stop parsing at the side change. This is true for the edited version you created in Premiere and the original file from Reaper. There must be some sort of EOF marker in there, so DTS Parser just stops parsing at that point, it won't look for another BOF after that point. So you need to split the wav at each side change, save each side as separate wav and run each of them through DTS Parser separately.
10. Open each of the .dts files created by DTS Parser in XVI32, run Schorman's script on each one (go to the XVIScript menu, click on Editor, paste in the script:

Code:
ADR 0
REPLACEALL 7F FE 80 01 FC 7C E0 02 63 A0 0D 3A 80 09 BY 7F FE 80 01 FC 7C DF F2 62 C0 0D 3A 80 09
ADR 0
EXIT

and click execute). Save the edited .dts file, close it and open the next, run the script again, save it, close it and open the next... until all sides are done.
11. Join all the now fixed dts files together using EAC3To:

Code:
"c:\program files (x86)\eac3to\eac3to" "G:\temp\Nutty Professor DTS_Edited.wav.fixed.dts"+"G:\temp\Nutty Professor DTS_2.wav.fixed.dts" "G:\Temp\Nutty Professor Final.dts"

11. The final "gotcha" with the DTS is that DTS Parser will have stripped out all of non DTS stuff at the beginning of your recording. If you didn't edit out the "play"... "Search Chapter 1" screens at the beginning, basically everything before that square wave of noise begins has been stripped away, so your audio may well be out of sync again. The solution to this is to go back to your Premiere project and look at the timeline. You should be able to see exactly where the DTS signal begins. Here you can see that mine begins at 13 seconds, 19 frames:

[Image: 9uMm3cm.png]

Which means I need to add a delay to the audio of 13792 ms (13 seconds = 13000 ms + 19 frames (1/23.976 * 1000 * 19 = 792)) when I combine my final .dts file with the .mp4 video file I exported earlier from Premiere in MKVToolnix.

[Image: PFqeMNx.png]

And that's it.
The007Dossier
TheStarWarsTrilogy
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Thanks given by: PDB , bronan , SwatDB , captainsolo , DoomBot
#42
Hello everyone, I tried to capture with reaper, but the capture has no sound. I set up as it was shown, and I had the same problem as HippieDalek. Once the problem is corrected, I start capturing, and I don't have any sound on this one.
Can you tell me if there is a problem here?

https://image.noelshack.com/fichiers/202...image1.png
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#43
That is really strange since the volume meters are showing sound coming through. Can you hear it if you monitor?
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#44
During or after the capture, I hear nothing.
On this screen, there the sound was paused, I have -5.7 and -2.7 (on the image at the bottom left) from the start.
And -5 +6 on project 1
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#45
What kind of capture equipment are you using?
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#46
It is not me, but a friend who is trying to capture his LD with Reaper.
He uses a "CSL USB 7.1".
On Audacity the capture works (except that we don't get the famous bitperfect on audacity)
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#47
Two ideas, 1 is that it does not like the ASIO driver. Perhaps try a different driver in settings? The other is that a lot of devices just resample everything coming through to 48 kHz, but I'm thinking even if thats the case you'd still hear something - it'd just sound a little choppy.
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#48
Ok thank you, I will try again when I will go to see my friend Smile
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#49
(2020-05-14, 03:17 PM)Falcon Wrote: On Audacity the capture works (except that we don't get the famous bitperfect on audacity)

16 bit audio can be captured without alteration of the audio in Audacity as well. The trick here is to select either 24 bit or 32 bit floating point during the recording session and save the result to 16 bit to avoid the dithering. Otherwise, the least significant bit will be altered, corrupting any AC3 or DTS data.

Also, I'd suggest using WASAPI as the interface.
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Thanks given by: bronan , Falcon
#50
I thought I had posted this before, but there's a tool that will replace the process of using dtsparser and then xvi32 to fix the frame headers. It's called "Wav2dts". It was developed by tebasuna over at doom9, and altered a bit by me to make it more usable with LaserDisc captures.

It can basically be used as a drag and drop interface on windows. Drag the Wav file you've recorded onto the .exe, and it will strip any padding from the beginning and end, convert to 16bit standard dts format, and correct all of the frame headers, in one step.

[Image: x953qx.png]

Here's the compiled version and source code:

https://mega.nz/#!DZUXTKRa!VJIvzhMSa4Fit...ecUZT4cOaU
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Thanks given by: PDB , bronan , williarob , Falcon , pipefan413


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