CDs Dead In 2012?

[johnfull]

I'll stick with lossless forms of compression like flac and png, thanks very much

Yeah, I'm just trying to salvage what I can from 25 years' CD purchases.
FLACs can be saved in DVD-A format very easily. I have been going through
long-neglected vinyl and open reel tapes and converting first to .wav 24/96
and then to FLAC to save to DVD-A format via DVD-AudioFile. Very easy
and the results are usually much easier on the ears...

 

[MDS]

Just wondering if calling MP3 data PCM is really accurate. Each MP3 frame is divided into a series of frequency/amplitude components right? Not sure if one could still call this just PCM.

Steve

Yes, during the encoding process and it is those 'sub-bands' that it analyzes to determine what to keep and what to chuck. The result of encoding is a stream of PCM samples but they are not in simple linear order like a raw bitstream or WAV file.

 

[johnfull]

Yes, during the encoding process and it is those 'sub-bands' that it analyzes to determine what to keep and what to chuck. The result of encoding is a stream of PCM samples but they are not in simple linear order like a raw bitstream or WAV file.

Is Dolby Digital (AC3) similar to mp3?
When it discards info, it has to save spatial information for the 5.1 format.
This would make the algorithms more complex, but it still manages to occupy
a small file size relative to 2-channel CD sound...

 

[TLS Guy]

Is Dolby Digital (AC3) similar to mp3?
When it discards info, it has to save spatial information for the 5.1 format.
This would make the algorithms more complex, but it still manages to occupy
a small file size relative to 2-channel CD sound...

AC3 is a superior algorithm to mp3. It can be used at varying bit rates. It is stall a lossy format with most of the bits chucked on the floor.

The BBC use it for their BBC iplayer. In the US it streams at 180 kbs, in the UK at 350kbs. It if preferred in the UK at 350 to analog FM and DAB

The BBC also stream from custom deigned and built servers as part of their Coyopa program.

 

[johnfull]

AC3 is a superior algorithm to mp3. It can be used at varying bit rates. It is stall a lossy format with most of the bits chucked on the floor.

The BBC use it for their BBC iplayer. In the US it streams at 180 kbs, in the UK at 350kbs. It if preferred in the UK at 350 to analog FM and DAB

The BBC also stream from custom deigned and built servers as part of their Coyopa program.

When given a choice between AC3 and DTS, I prefer DTS. It apparently doesn't use phychoaccoustic compression and is therefore bulkier. It sounds awful on commercial DTS-CDs, though, so it has its limits, but it sounds perfect at 24/96, to my ears.

Blu-Ray features lossless DTS and Dolby tracks. I've not auditioned those,
but it seems to be overkill and will lead to more copy-protection schemes...

 

[MDS]

Is Dolby Digital (AC3) similar to mp3?

Yes, it is similar in concept as are all 'lossy' compresssion schemes that use perceptual coding techniques to remove sounds its model thinks you wouldn't hear to reduce file size (and by extension the bit rate necessary for streaming).

The algorithm used to do the encoding is of course totally different. It too produces PCM samples.

 

[avnetguy]

Yes, during the encoding process and it is those 'sub-bands' that it analyzes to determine what to keep and what to chuck. The result of encoding is a stream of PCM samples but they are not in simple linear order like a raw bitstream or WAV file.

Correct if I'm wrong here but the result of the encoding is stored with the frequencies (sub-bands) with amplitudes still divided up.

The encode process as I understand it is,

PCM data -> FFT -> psychoacoustic modeling -> MP3 data.

The decode process is,

MP3 data -> inverse FFT -> PCM

Sound right?

Steve

 

[MDS]

Correct if I'm wrong here but the result of the encoding is stored with the frequencies (sub-bands) with amplitudes still divided up.

The encode process as I understand it is,

PCM data -> FFT -> psychoacoustic modeling -> MP3 data.

The decode process is,

MP3 data -> inverse FFT -> PCM

Sound right?

Steve

Yes, except to be more clear I'd say the input to encode and the result of decode is linear PCM. The 'MP3 data' is PCM too, just not linear and not directly DACable (is that even a word? )

 

[avnetguy]

Yes, except to be more clear I'd say the input to encode and the result of decode is linear PCM. The 'MP3 data' is PCM too, just not linear and not directly DACable (is that even a word? )

Yes, the input to encode and output resulting from decode are PCM but the encoded MP3 is not truely PCM anymore. Yes, I know, I'm spliting hairs here.

PCM is just a simple digital representation of the analog signal while inside each MPEG frame resides data now split into specific frequency components with some frequency components removed. In order for the PCM to be reconstructed some fairly complex math is involved before the PCM is DACable (should be added to dictionary). Now since some mathimatical procedure is required to restore it can it really still be called PCM?

Steve

 

[johnfull]

PCM is more specific than binary code, perhaps.
Is SACD considered PCM? I don't think DTS is.
DTS is my format of choice for multi-channel, so long as it's run at 24/96.
What a weird waveform, though! DSD looks like solid white noise, but
DTS is weird, gnarly stuff on a scope.
My old Yamaha receiver predates HDMI by a year or two and it will not
equalize signals from the multi-analog input. SACDs have to play flat as
do DVD-As in the MLP format. DTS, though, is picked up as a digital signal
and is equalized and bass managed properly. It's got better sound than the
Dolby Digital surround that is the default format on DVD-V and some DVD-As.
I understand that the licensing on DTS is quite a bit more stringent. Pity that...

 

[MDS]

Yes, the input to encode and output resulting from decode are PCM but the encoded MP3 is not truely PCM anymore. Yes, I know, I'm spliting hairs here.

PCM is just a simple digital representation of the analog signal while inside each MPEG frame resides data now split into specific frequency components with some frequency components removed. In order for the PCM to be reconstructed some fairly complex math is involved before the PCM is DACable (should be added to dictionary). Now since some mathimatical procedure is required to restore it can it really still be called PCM?

Steve

Ok, maybe it's not strictly correct to call it PCM because it is no longer of a fixed word length for each sample, so let's call it 'encoded' PCM. When the decoder is done with it, it's PCM again.

After the process of converting to the frequency domain and getting rid of what the model deems inaudible, the remaining components need to be coded and each is assigned a variable number of bits. If you're encoding at 320 kbps, you have 320K bits to represent the 705,600 bits of the original one second of 16/44.1 PCM samples. Those 320 kbits per second are what is stored. I don't think the original frequency component bins or 'sub bands' are stored directly, they are just part of the process to create the coded audio samples.

So yeah, after a lot of complex math, the decoder turns it back into 16/44.1 PCM although it's different now because much was removed from the original.

 

[avnetguy]

I don't think the original frequency component bins or 'sub bands' are stored directly, they are just part of the process to create the coded audio samples.

Its my understanding that the sub bands are what is stored, that's how the high levels of compression are achived. The less sub bands (higher masking) the lower the bit rate and quality. Of course it's much more complex than just saving FFT data, numerous algorithms are involved here, some for encoding while others try to correct/limit problems with the encoding.

Steve

 

[Stereodude]

Is SACD considered PCM?

No, it's DSD

I don't think DTS is. DTS is my format of choice for multi-channel, so long as it's run at 24/96. What a weird waveform, though! DSD looks like solid white noise, but DTS is weird, gnarly stuff on a scope.

Because you're trying to interpret an encoded compressed audio stream as if it were normal PCM audio.

My old Yamaha receiver predates HDMI by a year or two and it will not
equalize signals from the multi-analog input. SACDs have to play flat as
do DVD-As in the MLP format. DTS, though, is picked up as a digital signal
and is equalized and bass managed properly. It's got better sound than the
Dolby Digital surround that is the default format on DVD-V and some DVD-As.
I understand that the licensing on DTS is quite a bit more stringent. Pity that...

You could always get a receiver with HDMI and a HDMI equipped universal player and then have proper bass management for DVD-A & SACD.

 

[sholling]

DTS is my format of choice for multi-channel, so long as it's run at 24/96.

I use multichannel FLAC.

 

[johnfull]

I use multichannel FLAC.

What kind of player? DVDs can only read 9.6 megabits/second.
That's not fast enough without Meridian Lossless Compression...

 

[johnfull]

You could always get a receiver with HDMI and a HDMI equipped universal player and then have proper bass management for DVD-A & SACD.

The player has HDMI. I picked up a secondhand Pioneer Elite from 2004
last year. I got it home to find that there was no input on the Yamaha for
the HDMI and no way to digital-out otherwise. Bummer. Meantime, though,
I've discovered easy to use tools for extraction and reformatting and authoring
DVD-A discs to make the most of the content that I do own. SACDs are a different
story, though, since they can't be read on my PC.
The Yamaha's 7.1 sound field generator does a pleasant job with high quality stereo inputs.
I've got DVD-As, though, that have 24/96 5.1 DTS content and they sound
superb. They mostly sound ok in 2 channel straight from the original disc, but
the multi-channel has to be played without pre-amp functionality.
DTS in 24/96 5.1 plays flawlessly on any old cheapie DVD player as well, so
it's really my format of choice. I could conceivably take the DSD and
convert it to DTS in order to enjoy multi-channel equalized sound, but that
would require a new receiver with HDMI capability and it would have the
ability to equalize the original signal, thus defeating my little scheme's purpose...

 

[Stereodude]

SACDs are a different story, though, since they can't be read on my PC.

FWIW, they can be ripped to high res PCM with a properly equipped PS3.

 

[sholling]

What kind of player? DVDs can only read 9.6 megabits/second.
That's not fast enough without Meridian Lossless Compression...

I play my multichannel FLACs from a home media player (NeoTV550) not DVD-A. The only audio discs that I still use are SACD, everything else has been moved to hard drives in FLAC formats. I don't have a lot of SACDs so it's not worth the time and effort to figure out how to convert them.

 

[Rickster71]

CD-format to be abandoned...
I can't think of a better way to get the sheep into a buying frenzy.

I highlighted a few quotes from the article:
"The major labels 'plan' to abandon the CD-format by the end of 2012 (or even earlier)"
The operative word being "plan." If they can recreate a demand as they did for the once abandoned LP format, I think that plan will change.

"CD's cost money, even when they don't sell because there is stock storage to be paid; a label also pays money to distributors when CDs get returned to the labels when not sold and so on."
I call BS. It's more difficult to stock and transport larger LPs, but they still do that.

 

[johnfull]

CD-format to be abandoned...
I can't think of a better way to get the sheep into a buying frenzy.

I highlighted a few quotes from the article:
"The major labels 'plan' to abandon the CD-format by the end of 2012 (or even earlier)"
The operative word being "plan." If they can recreate a demand as they did for the once abandoned LP format, I think that plan will change.

"CD's cost money, even when they don't sell because there is stock storage to be paid; a label also pays money to distributors when CDs get returned to the labels when not sold and so on."
I call BS. It's more difficult to stock and transport larger LPs, but they still do that.

LPs are considered an audiophile format these days, unlike CDs.
There is nothing better for the record labels than a high-quality format
that will self-destruct with proper usage. It's why I think DVD-A is going
nowhere. The studios will never relinquish their right to make you pay for
the same work over and over again forever. Buy audiophile LPs, play them
one time with extremely expensive turntable and stylus and record them
into 32/196 .wav format for posterity. The studios should invest in the
stylus industry, obviously...