non 16-bit/44.1kHz audio

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sbooth
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non 16-bit/44.1kHz audio

Post by sbooth »

Because of its roots, Max only supports 16-bit 44.1kHz audio internally. All audio is converted to this format during internal processing- so anything with more bits per sample or a higher sample rate is downsampled during conversion.

Is there any interest/need to support different sample sizes/sample rates?

shanecavanaugh
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Post by shanecavanaugh »

SACDs and DVD-Audio discs use higher bitstreams (is that the right term?) and sampling frequencies. There aren't many releases in each format, though there are some releases by well-known musicians.

Higher fidelity support might also be of interest to field recorders, among whom 24-bit/96kHz is becoming standard.

Forward compatibility is a good reason as well.

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phule
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Post by phule »

shanecavanaugh wrote:SACDs and DVD-Audio discs use higher bitstreams (is that the right term?) and sampling frequencies. There aren't many releases in each format, though there are some releases by well-known musicians.

Higher fidelity support might also be of interest to field recorders, among whom 24-bit/96kHz is becoming standard.

Forward compatibility is a good reason as well.
I wonder if `hybrid' use the same or different rates.
Bob

Rawklixx
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Music DVDs

Post by Rawklixx »

The ability to use Max for audio larger than 16-bit 44.1kHz would be VERY useful for me. The only DVDs I buy are music/concert. I've been extracting the data with Mac The Ripper and go through somewhat clumbersome routes to rip them into 24-bit mp3s. So for me this feature would be very nice.

I love this program, please keep up the great work!

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Post by shanecavanaugh »

phule wrote:I wonder if `hybrid' use the same or different rates.
Hybrid discs include both a Red Book-standard layer that can play in any CD player and the SACD layer, which requires a SACD-compatible player.

Actually, now that I think about it, and after some googling, I don't think that there are optical computer drives (Apple or otherwise) available that are compatible with SACD or DVD-Audio. So ixnay that reasoning.

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Post by sbooth »

Obviously this would only be implemented for file conversion; as Shane said I don't think any computer cdrom/dvd drive supports SACD (yet).

Each non-PCM format supports slightly different bits per sample and sample rates.

The lossless formats support the broadest spectrum of bits per sample/sample rates. FLAC supports up to 655350 Hz and 4-32 bits per sample. I can't find the specs for Monkey's Audio, but I presume it is similar to FLAC. WavPack supports 8-32 bits per sample at 6 - 192 kHz.

As best I can tell the highest sample rate supported by LAME is 48 kHz, and I'm not sure about the sample size. Ogg Vorbis supports 8 - 48 kHz and 16+ bits per sample.

I suppose that Max will just support what the format supports; in case of a lesser bits per sample or sample rate, the audio would have to be resampled. I would think anyone with non 16-bit/44.1kHz audio would be prepared for this!

This is something I will look into implementing for future versions, since there appears to be interest.[/i]

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Post by woody77 »

SACD is a very different format than DVD-A and Redbook. SACD isn't PCM, but is DSD (or DSS, I forget which acronym). The input audio is sampled at ~2MHz, and is encoded as a 1 or a 0 if higher or lower than the previous level sampled. So it's just a continuous stream of 1s/0s saying higher/lower. Not actual samples captured into n bits.

I beleive it's also called delta-sigma sampling.

Anyway, frequency response is to 100KHz or so.

Sony owns the format, and they're currently refusing to let it leave the player in digital format. They only want analog interconnects, so that it doesn't get pirated... Makes our life interesting, that's for sure.

I agree that we should max out what the format will support, if we're trying to encode data that's been ripped at a higher rate than standard redbook. Or, add some prefs to control that (maybe on a per-encoder basis, so the FLACs and APEs can be 24b/48K, WavPack 24/192, and MP3 at 24/48 (since it doesn't make sense to resample from 48 to 44.1, and 48 is the nice base rate for all the other high sample rates, and is a totally cake downsampling operation).

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phule
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Post by phule »

woody77 wrote:SACD is a very different format than DVD-A and Redbook. SACD isn't PCM, but is DSD (or DSS, I forget which acronym). The input audio is sampled at ~2MHz, and is encoded as a 1 or a 0 if higher or lower than the previous level sampled. So it's just a continuous stream of 1s/0s saying higher/lower. Not actual samples captured into n bits.

I beleive it's also called delta-sigma sampling.

Anyway, frequency response is to 100KHz or so.

Sony owns the format, and they're currently refusing to let it leave the player in digital format. They only want analog interconnects, so that it doesn't get pirated... Makes our life interesting, that's for sure.

I agree that we should max out what the format will support, if we're trying to encode data that's been ripped at a higher rate than standard redbook. Or, add some prefs to control that (maybe on a per-encoder basis, so the FLACs and APEs can be 24b/48K, WavPack 24/192, and MP3 at 24/48 (since it doesn't make sense to resample from 48 to 44.1, and 48 is the nice base rate for all the other high sample rates, and is a totally cake downsampling operation).
How would so-called "hybrid" SACDs fit? They supposedly will play in either a regular CD player or a SACD player. What format are they?
Bob

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Post by shanecavanaugh »

From the SACD Wikipedia article:
The most popular of the three types, hybrid discs include an audio CD "Red Book" layer compatible with Compact Disc players, dubbed the "CD layer," and a 4.7 GB SACD layer, dubbed the "HD layer."
So the "CD layer", which is playable in standard CD players , doesn't offer higher quality than a regular CD.

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Post by woody77 »

The wikipedia article pretty much nails the explanation of SACDs and the hybrid discs.

BTW, I have the <i>Dark Side of the Moon</i> SACD (hybrid), and you can definitely hear a difference between the two layers on my (modest) equipment:

- Denon 1920 CD/DVD/DVD-A/SACD player
- Marantz SR5500
- Polk Monitor7s (definitely the weak link)
- Custom sub (1cu ft, sealed 10").

Anyway, the main difference between the two layers was in the reproduction of the high guitar "wails" and in the cymbols. Just a lot less distortion involved.

However, my Denon might be doing a high bitrate PCM conversion before the D/A stage. If so, then the gains are similar for DVD-A, as well.

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Update

Post by sbooth »

I have implemented 8, 16, 24 and 32-bit file conversions for Max for the formats that support these frame sizes (PCM, FLAC, WavPack, Monkey's Audio). Also, the original sampling rate for audio not at 44.1kHz should be preserved.

For formats that don't support these sample sizes I tried to take a "best approximation" type approach.

NormalInk
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Re: non 16-bit/44.1kHz audio

Post by NormalInk »

I work at a trailer house and the editors here use Final Cut Pro, which works best with 16 bit, 48k aiffs. Currently, since CDs are 44k, Max outputs aiffs I rip from CDs or other 44k sources at 44k, but I would really appreciate a way to force it to output in 48k. My solution for now is to use a quicktime batch converter to upconvert, but it's not a very clean system. Thanks!

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