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Topic: Encoding & Decoding - same file at the same time (Read 2022 times) previous topic - next topic

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Encoding & Decoding - same file at the same time
I have some technical questions, I have looked at the forums and this seems to be a great place to ask.

I have been contracted to develop an audio application that requires long duration recording - several hours at a time.  However, they want to be able to scan and listen to the recording on the fly.

My preliminary demo application was developed in Visual Basic 6. (I'm truly ashamed but the schedule is intensely short)

I have the recording component completed and decided MP3 was my best option for compression (I was also looking at OGG because of MP3 licensing issues). 

My issue arises in playing back that MP3 file as it is still being recorded - I do not need to be able to play it live, but I need to be able to seek through the file, go back and play 2 minutes of audio that was recorded 40 minutes ago. 

I have a few options, such as the Windows Media Player control - it runs like dirt on a streamed file like this.  Also the audio length stays as what it was when the file was first opened so that as it plays the progress sticks to 100% done so there is no way to scan through the file. 

Other option is the super simple MMControl, which does not even allow scan/seeking in a song – it offers play/pause and stop.

I've also tried the ActiveMovie control type library; wish would be amazingly perfect, if it could access the file.  It gives an error saying it cannot open the file because it is open by another process. While it is true, the other libraries give no errors.

I've tried using the winamp plugins and using a wrapper, but was unable to get them to function.  I doubt it would help because Winamp has the same issue with updating file length - at least play position updates, saying it's played to 00:50 when the file is only 00:03 long.

I've also tried this RSP MP3 Player OCX that is spewing out of the cracks during Google searches - my issue with that one of course is it's price - and just like the others has the same seek/scan problem.

It's such an obscure issue; I'm rather desperate for a solution - if anyone has any advice or suggestions, I would be greatly thankful.

Encoding & Decoding - same file at the same time
Reply #1
No one knows? :\

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Encoding & Decoding - same file at the same time
Reply #2
Make copies before you access 'em.  Update the copy every x seconds.  Since you're only playing back at realtime, you'll never get past the end of the file anyways.  Or at least, it shouldn't be too much of an issue.  Just make sure you check, every time you seek, if you go out of bounds of the file.