Author Topic: Stream playback  (Read 4371 times)

Torkell

  • Posts: 1169
Stream playback
« on: 14 Jul '03 - 16:49 »
Here's another couple of questions for you, Ian:

If I have a 16-bit stereo 44.1kHz MP3/OGG/WAV, and I play it back at 32-bit 96kHz (or as near to that as the sound card goes), what happens to it. Does the interpolation affect it at all?

Also, I have a little problem with OGGs & XMPlay - I create a OGG (typically ~152kb/s) from a WAV file (that was from a CD), all at 16 bit 44.1kHz, and then play it back with XMPlay. When I play the OGG, XMPlay decides that 64 is too high an amplification setting. With the WAV, the AAR remains static on 64 quite happily. Why? The WAV was produced using RealOnePlayer, and the OGG using XMPlay and OGGENC.

Ian @ un4seen

  • Administrator
  • Posts: 20437
Re: Stream playback
« Reply #1 on: 14 Jul '03 - 21:26 »
Quote
If I have a 16-bit stereo 44.1kHz MP3/OGG/WAV, and I play it back at 32-bit 96kHz (or as near to that as the sound card goes), what happens to it. Does the interpolation affect it at all?

No. Firstly, XMPlay will play the MP3/OGG/WAV at 44.1khz - the sample rate setting only applies to MODs... in fact, so does the interpolation option ;D

Quote
Also, I have a little problem with OGGs & XMPlay - I create a OGG (typically ~152kb/s) from a WAV file (that was from a CD), all at 16 bit 44.1kHz, and then play it back with XMPlay. When I play the OGG, XMPlay decides that 64 is too high an amplification setting. With the WAV, the AAR remains static on 64 quite happily. Why? The WAV was produced using RealOnePlayer, and the OGG using XMPlay and OGGENC.

If the original WAV's optimal amp level was 64, there's a good chance that it contained clipped samples. In that case it's very possible (likely even :)) that a lossy compressed (OGG) version will clip slightly... you can check by writing a 32-bit WAV of it (with auto-amp disabled), and looking at that in a sample editor.

Torkell

  • Posts: 1169
Re: Stream playback
« Reply #2 on: 15 Jul '03 - 16:54 »
Thanks. That would explain why my ripped OGGs decide to play back at 60 or worse for the amp. Any chance of modifing this, as in theory, since OGGs are simply a lossy representation of a file with a finite level (approx +/- 2^15 for 16 bit files), there should be no need to reduce the amplification below 0dB?

Ralesk

  • Posts: 654
Re: Stream playback
« Reply #3 on: 17 Jul '03 - 09:29 »
| If the original WAV's optimal amp level was 64, there's a
| good chance that it contained clipped samples.

Isn't 64 the default?  In that case if it was also the optimal, clipping shouldn't occur, in my opinion. ???

Rah'Dick

  • XMPlay Support
  • Posts: 932
Re: Stream playback
« Reply #4 on: 17 Jul '03 - 10:46 »
I never understood the way, that amp bar is working... WAVs play perfectly but OGGs and MP3s of that WAV are producing strange noises - no other player does that, duh.  ::)

Ian @ un4seen

  • Administrator
  • Posts: 20437
Re: Stream playback
« Reply #5 on: 17 Jul '03 - 11:58 »
Quote

| If the original WAV's optimal amp level was 64, there's a
| good chance that it contained clipped samples.

Isn't 64 the default?  In that case if it was also the optimal, clipping shouldn't occur, in my opinion. ???

If a WAV file contains clipped samples, there's nothing XMPlay can do about it - whatever was clipped is gone. So there's nothing to be gained by XMPlay reducing the amp level.

The exception is if it's a non-clipped floating-point WAV file, in which case XMPlay can reduce the amp level to stop it clipping, just as it does with the MPEG/OGG/MOD formats.

Quote

I never understood the way, that amp bar is working... WAVs play perfectly but OGGs and MP3s of that WAV are producing strange noises - no other player does that, duh.  ::)

Upload please :)