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  1. Capturing Memories dellsam34's Avatar
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    I've seen projects for capturing VHS video tapes (VHS decode) and Teletext from Video tapes into PC using some sort of TBC software but I've never heard of a project for PC software that can recover PCM data from video frames, The only way of doing it is using an ancient PCM adapter device such as the Sony PCM-601ESD or the hardware attempt of someone from south Africa who has been working on this project for over a decade, this is his third gen design, the Corona virus lock down helped him focus more on this project.

    Since the video frames are just 0's and 1's represented by black and white blocks I'm thinking it is possible to make a computer software that can recover those bits into a usable PCM stream as digital wav audio.

    I'm sitting on a bunch of VHS PCM tapes and while I have the Sony PCM adapter to recover the audio from them I just though maybe someone with coding skills could start such a project for the sake of experimenting.

    Here is a sample from one of the tapes:
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    Last edited by dellsam34; 30th Nov 2022 at 12:41.
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  2. Member Cornucopia's Avatar
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    I would suggest that, since you have the adapter, you provide an "encoded" AND a "decoded" copy of the same segment, for reference verification purposes.

    Also note: there were other, similar processors - PCM-F1 was what I used back in the day (hooked up to a Umatic deck most of the time), and I think there were the 601/701 series as well. Those could assist in comparison.

    Also, part of the issue that dude is having is because he is assuming 44100 Hz sampling. It wasn't. It was 44056. And many of the processors were 14bit, only a few were 16bit.

    Scott
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  3. Capturing Memories dellsam34's Avatar
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    I would like to keep it a mystery unless someone has a PCM adapter to take a challenge and let us know what that 30 sec audio is. Fun! Isn't it?

    Anyway, No his problem has nothing to do with 44056 Hz because he is using an actual CD player to generate the signal and encode into video, Besides 44056 Hz recording didn't last long, It was replaced pretty quickly by 44.1 KHz which led to the birth of the DAT format and the additional 48 KHz. Sony PCM-601ESD being the only one with SPDIF IN/OUT and 16Bit capabilities.
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    What is the theory behind this tech? Why was PCM data encoded in a video stream?
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  5. Capturing Memories dellsam34's Avatar
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    Originally Posted by davexnet View Post
    What is the theory behind this tech? Why was PCM data encoded in a video stream?
    Back in the day video tape was the only mean to store a tremendous amount of digital audio data, DAT and CD where not on the scene yet, Some artists have mastered their audio tracks on U-Matic and Betamax formats and some semi pro used VHS and Video8 formats coupled to or built in a VCR.
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  6. Member Cornucopia's Avatar
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    Not the ONLY means (DASH, SoundStream, DigiStudio, etc), but this certainly put the means to record audio digitally into the hands of many, in a straightforward way, using existing storage formats that intrinsically had enough bandwidth.

    Scott
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  7. Capturing Memories dellsam34's Avatar
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    I'm back to this thread with some new information, On YouTube comments someone sent me a link to download a Windows GUI app for a PCM Decoder, Basically you load a captured PCM video or hookup live to a capture card from a VCR playing back a PCM encoded tape and it will decode the video and save as WAV audio file in 16/44.1.
    The attached package includes ni-labview-2019-runtime-engine to be installed first, then DSEG7Classic-BoldItalic second and then run the PCM Encoder by clicking pcm application.


    If you are interested in PCM Encoder and you like scripting, here is the encoder page:
    https://github.com/ololoshka2871/pcm_coder/releases/tag/v0.8
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    Last edited by dellsam34; 30th Nov 2022 at 12:45. Reason: Updated the link
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  8. Capturing Memories dellsam34's Avatar
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    Originally Posted by dellsam34 View Post
    I would like to keep it a mystery unless someone has a PCM adapter to take a challenge and let us know what that 30 sec audio is. Fun! Isn't it?

    The reveal !!!!
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  9. Capturing Memories dellsam34's Avatar
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    The latest Techmoan video about PCM recording motivated me to give the PCM encoder a try, It's a script based app but pretty straight forward, First I installed the package from github, Then extracted the folder and right clicked on it while holding shift key and chose commend line here, then in the DOS looking window I typed in the following commend, You can copy/paste it from here:

    Code:
    pcm_coder.exe --ntsc --16 "c:\FilePath\FileName.wav" "c:\FilePath\FileName.avi"
    Replace ntsc with pal for PAL and 16 by 14 for 14bit encoding.

    The video generated is AVI 720x525 for NTSC, it needs to be cropped to 720x480 with vdub (losslessly). After that you can play the file on a media player that has composite output and record to a VCR, Your music will be stored into VHS. Voila!

    Note: I imported the generated video file into the PCM Decoder app in post #7 and it played it without cropping, in setting you have to reverse the field order.

    Credit goes to Zcooger for his assistance.
    Last edited by dellsam34; 30th Nov 2022 at 12:48.
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  10. This is great! I love saving audio/video/data in weird, strange ways.

    I wonder if it is possible to save a digital video stream like this...

    Or convert video to audio (There are several funky programs for this, small-band/slow-scan television.) and save it as PCM...

    In the 90's there was a program and card that allowed you to save data backups with DOS/WIN 3.11/95 on VHS tapes. It used an ISA card in your PC to convert data to composite that you could then record on a VHS tape. And play back, of course.

    (I suppose you can use any video capture tape/device as long as it has sufficient resolution and stability.)

    16mm film hmmm....
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  11. Capturing Memories dellsam34's Avatar
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    Yah, I know what you are talking about:

    https://youtu.be/TUS0Zv2APjU
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  12. Capturing Memories dellsam34's Avatar
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    This is the first time I've seen digital PCM stored on 1" type C reel to reel video tape, Enjoy the song:
    https://youtu.be/jlt0m0vSEwc?t=1682
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  13. Originally Posted by dellsam34 View Post
    I'm back to this thread with some new information, On YouTube comments someone sent me a link to download a Windows GUI app for a PCM Decoder, Basically you load a captured PCM video or hookup live to a capture card from a VCR playing back a PCM encoded tape and it will decode the video and save as WAV audio file in 16/44.1.
    The attached package includes ni-labview-2019-runtime-engine to be installed first, then DSEG7Classic-BoldItalic second and then run the PCM Encoder by clicking pcm application.


    If you are interested in PCM Encoder and you like script $hit (I don't) here is the encoder page:
    https://github.com/ololoshka2871/pcm_coder/releases/tag/v0.8
    What the big F is Ich Troje doing on the tape? Surprised anybody knows this band? They are from my country, pretty legnedary in some circles.
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  14. I have done the reverse, storing video in the audio channel of cassette and reel to reel.

    Sure, it was only a few frames per second, and something like 120 or even 60 lines. But it was fun...

    I forgot what I stored. If I find the required programs I can make a short video of the recording.
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  15. I successfully decoded the sample provided using this software on Win7 x64 over VirtualBox with a Linux host

    PCM Data 16 _ 44056 .flac

    Here is my full post:
    https://www.tapeheads.net/showthread.php?t=82905

    Reply #17

    I'm also on this thread:
    https://forum.videohelp.com/threads/394168-Current-status-of-ld-decode-vhs-decode-%28t...nals%29/page10

    Good quality content!
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  16. Capturing Memories dellsam34's Avatar
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    It turned out that a hardware product has already been made, Here is a neat video explaining PCM audio on a video tape, I have no clue to how I missed it for the last few years I've been reading about the format unless it's a new product.
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  17. For your information - Fagear just released a public version of software decoder for multiple PCM video standards with fancy error correciton functions as well as source code available here: https://github.com/Fagear/SDVPCMdecoder
    👉 HackTV (Software Multistandard TV Signal Generator & Multiplexer) - Discord
    👉 Domesday86 Project Gargamel (Software LD/VHS Decoder & TBC) - Discord
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  18. Capturing Memories dellsam34's Avatar
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    What files needed to be downloaded and how to install them? Github file structure always confuses me.
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  19. For launchable EXE look in releases and click on "assets".
    https://github.com/Fagear/SDVPCMdecoder/releases
    Last edited by Zcooger; 30th Nov 2022 at 07:05.
    👉 HackTV (Software Multistandard TV Signal Generator & Multiplexer) - Discord
    👉 Domesday86 Project Gargamel (Software LD/VHS Decoder & TBC) - Discord
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  20. Capturing Memories dellsam34's Avatar
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    Total failure, Tried multiple files with multiple options couldn't get it to play without stutter, The PCM decoder you referred me to before is way better, Nice 80's looking interface, easy to understand options and just works with different types of files. I tried the latest beta release but they need to work harder, definitely not a finished product.
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    Hi all,

    My dsPIC33 solution is taking shape nicely now that I managed to get dsPIC33s capable of 100MIPS operation. The recording format is still proprietary, but I'm receiving a tape from Japan with PCM1630 format recorded on it to start working on backward compatibility.

    Previously the only stumbling blocks I ran into were insufficient CPU cycles and a DMA RAM buffer area that was too small. The new chips should solve these problems since the software essentially works.

    My 2007 Proof of Concept is here: https://myprius.co.za/pcmx1_processor.htm
    My 2008/10 experiments are here: https://myprius.co.za/pcmx2_processor1.htm

    The gap is due to life happening. Both my parents dying. Getting my Masters Thesis written...

    My 2021/22 experiments are here: https://myprius.co.za/pcm3_processor.htm

    Thanks
    Last edited by albertusj; 5th Dec 2022 at 14:35.
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  22. Capturing Memories dellsam34's Avatar
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    Nice progress, Slowly but surely, Looking forward to the final PCB.
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    Anyone get pcm.exe to run in windows 11? I've run the labview installer but I still get error message when trying to run pcm.exe. Image
    [Attachment 68094 - Click to enlarge]


    Edit: I was able to get this running in Windows 11.

    What I had to do:

    Go to Windows 11's Setting > Apps > Installed Apps > NI Package Manager. Click on the three dots and choose Modify.

    The NI Package Manager will open.

    Click on Programming Environments then Labview Runtime.

    Version 2022 Q3 and 64bit.

    Choose Install

    This will update the package. Once done, system requires a reboot.

    Once rebooted, pcm.exe should run if you right click and choose "run as administrator"
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    Last edited by Arnold_Layne; 11th Dec 2022 at 11:40. Reason: found solution
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  24. Capturing Memories dellsam34's Avatar
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    Had the same issue with Windows 10 and a new version of Labview solved the problem.
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