Is "lossy" audio always lossy?

[jsteinhauer]

If a soundtrack is recorded on equipment that is, let's say, less than the best, does it necessarily need to be encoded in in PCM, DTS-MA or TrueHD to be "lossless". If the original source maxes out at 640kbs, could not DD5.1 still be lossless?

[Kryptonic]

If the original source is not of the highest quality, then lossless isn't going to add much. Older films mixed before the advent of stereo usually don't benefit much and sound better in their original mono form, unless they're completely rerecorded and restored.

[cjones235]

So you are telling me that poltergeist,licence to kil, and blade runner all would have sounded better in lossy audio. Man get off it i don't care how old the movie is a remixed high bit-rate lossless audio will always sound better then the original analog recording if remastered properly. To make a long story short i don't care if the movie is from 1847 all films should lossless audio no matter what age.

[Uniquely]

Originally Posted by cjones235

So you are telling me that poltergeist,licence to kil, and blade runner all would have sounded better in lossy audio. Man get off it i don't care how old the movie is a remixed high bit-rate lossless audio will always sound better then the original analog recording if remastered properly. To make a long story short i don't care if the movie is from 1847 all films should lossless audio no matter what age.

Not really. There is no way to uprez audio. If a soundtrack was originally mastered at say 640kbs, then using a lossless codec really isn't going to add sound that was never there to begin with. Fortunately, most movies do have a master somewhere that can take advantage of higher bitrate formats, but if they do not... then it's rather pointless to use one just for the sake of using it.

[aramis109]

I wouldn't say there's NO WAY to "uprez" video, since the PS3 can convert it to a higher bitrate. Still, you can't add what isn't there.

Thing is, even if the source is 640kbs (which is unlikely since it's probably not digital only), there's nothing to say that outputting it in that way is going to capture every nuance, as some may be lost in the conversion. Truthfully though, outside of VERY old mono tracks, I'm betting there's no such thing as that, because you're dealing with an analog source, not a purely digital one, and just like film, you can probably glean more from it.

[Beta Man]

Originally Posted by cjones235

So you are telling me that poltergeist,licence to kil, and blade runner all would have sounded better in lossy audio. Man get off it i don't care how old the movie is a remixed high bit-rate lossless audio will always sound better then the original analog recording if remastered properly. To make a long story short i don't care if the movie is from 1847 all films should lossless audio no matter what age.

His point was, if the master contains information that can be reproduced without compression in a DD 2-channel audio track for instance...... it wouldn't benefit (nor suffer) from a 2-channel Lossless audio track, since the data would be identical.

I however don't know if that's true, and I don't know if original audio, even in monaural, exists that isn't compressed one way or another for DD DTS etc.


Thanks for putting this back into my head Aramis

[jsteinhauer]

Well now this is more interesting. I guess I am really thinking about digital masters. I admit, I know nothing about how movie soundtracks are produced. Are they (modern movies) usually recorded analog and the digitally mastered, or are they usually recorded digitally to begin with?

I would think, either way, that all masters are "lossy" compared to the original track. Of course you have to edit and clean it up, which is taking stuff out, but lossy versus lossless, I do believe, is with respect to the master. And compared to analog is a comparing quanta to bits. Creating a digital image of an analog source must be lossy.

I guess to be more specific, are there movies, especially lower budget or indies, that are either originally recorded digitally or originally mastered at low bitrates within the realm of the DD or DTS cores?

[wallendo]

Originally Posted by jsteinhauer

Well now this is more interesting. I guess I am really thinking about digital masters. I admit, I know nothing about how movie soundtracks are produced. Are they (modern movies) usually recorded analog and the digitally mastered, or are they usually recorded digitally to begin with?

I would think, either way, that all masters are "lossy" compared to the original track. Of course you have to edit and clean it up, which is taking stuff out, but lossy versus lossless, I do believe, is with respect to the master. And compared to analog is a comparing quanta to bits. Creating a digital image of an analog source must be lossy.

I guess to be more specific, are there movies, especially lower budget or indies, that are either originally recorded digitally or originally mastered at low bitrates within the realm of the DD or DTS cores?

There may be cases where the original audio was lost and the only surviving sound is DD, DTS, or similar. In this case, releasing a disk with the original mix in its original lossy format would reproduce the sound exactly.

I doubt that there are many major movies digitally mastered at anything less than 16-bit 48kHZ (or 44 kHz).

There may be older analog audio of poorer quality where a lossy track would not be distinguishable from a lossless track to a non-biased observer; in this case, it would still be to a studio's benefit to offer a PCM/TruHD/HD-MA track because there are many users who would complain otherwise, if not refuse to buy the disk.

[Kryptonic]

Originally Posted by cjones235

So you are telling me that poltergeist,licence to kil, and blade runner all would have sounded better in lossy audio. Man get off it i don't care how old the movie is a remixed high bit-rate lossless audio will always sound better then the original analog recording if remastered properly. To make a long story short i don't care if the movie is from 1847 all films should lossless audio no matter what age.

Just like OAR, sound should be about the right sound, not the louder sound with the most channels. Is Seventh Seal going to sound better in DTS-HD MA 7.1 instead of an uncompressed 1-channel mono? No, the original mono audio is going to sound better because it's the original recording and it's the right sound for the movie.

The movies you mentioned all featured multi-track stereo or Dolby surround audio and were very rich mixes for their time. A lossless DTS-HD or TrueHD version of these tracks would benefit them because they were mixed in multi-channel audio.

[ZoetMB]

Dolby AC-3 does a really terrific job at compression. I attended a demo once where they demonstrated what was lost.

The way that you do this is you play back the original multitrack along with the compressed version, but you play the compressed version out of phase with the original signal.

What you then hear is the "difference" between them.

What we heard was that every once in a while you'd hear an "ssss" for a half second or so. And that was it. That was the total difference between the lossless original and the lossy compressed version. Pretty amazing for a 10:1 compression.

What Dolby True HD does is combine the compressed AC-3 version with the difference signal (in-phase). The sum of both becomes the original "lossless" version and is only slightly bigger than the AC-3 file.

[KrugStillo]

I'm not 100% sure on this but I think, unless the track is lost, anything mastered digitally which is pretty much anything nowadays is initially mixed down to a Wav or PCM file anyway. I'm pretty sure movies aren't initially mixed in DD or DTS, that's an after product of the finished Wav or PCM mix. So in that case PCM is the original track. Even a low budget movie would still have the Wav or PCM track that they originally mixed. On a low level I make movies and edit them on Adobe Premiere. Now I don't put the Wav files on a DVD because it takes up too much space but I do still have them. So if I have them I'm pretty sure most studio pics definitely have them. So really there is really no reason to not include lossless audio on a BD. Obviously there is no way we are going to get the mixing board with the original materials in our houses. But then again, someone correct me if I'm wrong, DD and DTS don't get that either. They get a mixed Wav or PCM track to convert. So in essence you can't even have DD without PCM. I hope this clears some things up.

[radagast]

Originally Posted by jsteinhauer

If a soundtrack is recorded on equipment that is, let's say, less than the best, does it necessarily need to be encoded in in PCM, DTS-MA or TrueHD to be "lossless". If the original source maxes out at 640kbs, could not DD5.1 still be lossless?

Purely from a definition standpoint, If something is really "lossless" then when it is uncompressed, it will be bit-for-bit the same as the original before compression. Remastering is a different subject. Removing or reducing hiss, pops and cracks, and eq can help improve the sound before compression.

[kevinbr100]

I think you guys are missing the point. Lossy codecs are ALWAYS lossy, so that means that they remove some data from the original source, regardless of the quality of the original source, as part of its compression technique. So irregardless of the bit rate or resolution it is encoded at, just by the very nature of a lossy codec, some data will be lost. Whether this data is perceivable to the human ear is always debatable, and may vary from individual to individual/

[42041]

Originally Posted by jsteinhauer

If a soundtrack is recorded on equipment that is, let's say, less than the best, does it necessarily need to be encoded in in PCM, DTS-MA or TrueHD to be "lossless". If the original source maxes out at 640kbs, could not DD5.1 still be lossless?

No, that's not how perceptual codecs work.
And if the original source is lossy Dolby Digital, recompressing it again with the same encoder will not yield identical output, but add further compression artifacts.

[Trogdor2010]

Most non digital films before the 90's have been recorded in an analog format, whether monural or multichannel. Depending on the quality of the analog format, lossless audio may benefit the picture when they remaster it. Digital information is recorded with computer files and no realistic way to enchance the audio, unless if there is an intention to remaster or even rerecord the audio of the film.