How do you compress LPCM audio in a MPEG2 video file?

[starionx]

I'm capturing a TV broadcast using WINDVR 3. My capture card (Adaptec VideOh Media Center USB 2.0), will only record in mpeg2 (mpeg1 as well, but I'm not using that). The only audio choice I get is LPCM. The problem with this is the audio stream is huge!
How can I separate the audio and video streams, compress the LPCM file, then put the 2 files back together again?
If it's possible, a step by step would be appreciated.

[Tommyknocker]

TMPGEnc. File-->MPEG Tools...-->Demux.

[Marco33]

Second, To change the file to a AC3 sound file (DVD standard). I use BeSweet (and the BeSweet GUI) for that. I open the BeSweet GUI (an overlay for the BeSweet program, sort of like the way windows 3.1 worked over DOS... I digress) You need to tell BeSweet GUI where the the Regular BeSweet.exe is, where the WAV is and where the new AC3 file will be saved. Click the Wav to AC3 button.

[BJ_M]

Install tmpgenc and open it -> file -> mpeg tools -> simple demultiplex -> demultiplex the audio and video streams

part 2

get GOLDWAVE or Sound forge (doesnt mater which)

file open (* all file types) -> you audio file you saved in first step (named somethign like *.pcm)
-> the file type you will have to select is "RAW" type -> PCM 16 bit , BIG Endian , stereo, 48khz (might be 44.1 in your case - i dont know) ..
You will have to manually select all of the above things as a LPCM file is a raw file (no info to the sound app) ..



save the file as mpeg1 audio layer 2 , 48khz, stereo , 196 bit rate


part 3

open tmpgenc again -> file - > mpeg tools -> simple multiplex -> file tpye "program mpeg2"
add you new audio file -> add the video file you saved in step one (*.m2v)
-> multiplex

-> done

[thayne]

Then use BeSweetGui to convert the demuxed sound file to mpeg layer 2 audio.

Then use TMPGenc mpeg tools to re-mux the new audio file with the video file

[BJ_M]

i should mention that- though besweet is a fine tool -- it cant open RAW LPCM streams ... as you mentioned you had ..

[starionx]

Install tmpgenc and open it -> file -> mpeg tools -> simple demultiplex -> demultiplex the audio and video streams

part 2

get GOLDWAVE or Sound forge (doesnt mater which)

file open (* all file types) -> you audio file you saved in first step (named somethign like *.pcm)
-> the file type you will have to select is "RAW" type -> PCM 16 bit , BIG Endian , stereo, 48khz (might be 44.1 in your case - i dont know) ..
You will have to manually select all of the above things as a LPCM file is a raw file (no info to the sound app) ..



save the file as mpeg1 audio layer 2 , 48khz, stereo , 196 bit rate


part 3

open tmpgenc again -> file - > mpeg tools -> simple multiplex -> file tpye "program mpeg2"
add you new audio file -> add the video file you saved in step one (*.m2v)
-> multiplex

-> done

Ok. I demultiplexed using TMPGenc, I opened the WAV file in GoldWave, but you lost me a little as to how to compress the file. What am I supposed to do in GoldWave to actually compress the file, or are you saying to just Save File As, and then choose the type you want which will compress the file for me?

I very much appreciate the help.

[BJ_M]

if you dont have the mpeg compression in goldwave - just save it as a wav and compress the wav to mpeg 1 layer 2 audio in tmpgenc instead (in sound forge you can open and compress) ..

if you truly had a wav file (and not raw lpcm) to start with -- you can compress it direct in tmpgenc or as with besweet as mentioned ..

[starionx]

if you dont have the mpeg compression in goldwave - just save it as a wav and compress the wav to mpeg 1 layer 2 audio in tmpgenc instead (in sound forge you can open and compress) ..

if you truly had a wav file (and not raw lpcm) to start with -- you can compress it direct in tmpgenc or as with besweet as mentioned ..

I finally figured it out!
Sorry about the confusion with the PCM and WAV formats. My decoder card software says it is recording in LPCM. When I convert the MPEG2 file into VOB structure, and open up the files in DVDShrink, it shows the audio file as LPCM, so had to assume that's what it was. The reason I mentioned WAV, was that tmpgenc was defaulting the output audio file to WAV.
In the end, I used the WAV default for the Demultiplexing (and I also didn't have to use GoldWave). The bottom line is that it worked, the audio sounds good, and I get to reduce the mpeg file size. 8)

Thank you very much for your help BJ_M