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Topic: MAC (APE) lack of streaming feature - what does it mean? (Read 4503 times) previous topic - next topic
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MAC (APE) lack of streaming feature - what does it mean?

Hi again folks,

Sorry about this dumb question, but why is it not right to believe that APE does not have streaming feature although I do stream the APE files from a SMB share all the way to the VLC application (using ATV4K box). Does anything happen in this process that VLC transcode on-the-fly the APE into PCM and, with FLAC, it would pass-through directly? If VLC is in fact passing-through the APE file, is it the counting time lag (it delays and updates the timing progress bar each 6 seconds or so) that is bugged so this is not to be considered as a true stream as FLAC or ALAC? Or is it because it might be considered somewhat able to be streamed but not to the point of selling this idea to every and each hardware, because it's quite CPU consuming?

I'd like technical views on this.

Thanks a lot!

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #1
Streaming as in broadcasting such as internet radio or other kinds of live streams isn't supported.

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #2
Hi again folks,

Sorry about this dumb question, but why is it not right to believe that APE does not have streaming feature although I do stream the APE files from a SMB share all the way to the VLC application (using ATV4K box).

That isn't streaming, you're just loading the file from your network drive, so doesn't apply to you. 

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #3
Generally the wiki's lossless comparison needs a few more "why the hell should I care about this?!".
(... which certainly is a matter of tech progress. Nowadays, using a corporate codec gets you a measly 11 months of music onto your 5 TB portable 2.5" drive, but choosing a different format might give you a full year. Perspectives, perspectives ...)

... and the TTA devs still have gotten away with filling in "Pros" like "Symmetric algorithm" and the undocumented "Ultra low latency".

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #4
"Ultra low latency" could only have anything to do with the frame size of the codec.

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #5
Which is slightly more than a second. That number corresponds to 46080 samples at CDDA.
Reference FLAC defaults to 4096 samples.

So the only thing we have to go by, is a figure of 11.25x default FLAC.
(And if that figure matters: TTA sets it in stone. No options. Pick FLAC and -b 1152 for 1/45th of TTA.)

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #6
Which is slightly more than a second. That number corresponds to 46080 samples at CDDA.
Reference FLAC defaults to 4096 samples.

Frame or block size doesn't necessarily equal latency. FLAC encoder and decoders do indeed process one block at a time, having a latency of one block, but that isn't necessarily the case for other formats. One could also create a format that can be encoded and decoded on the fly, while reading/writing the block. That seems to be possible with TTA, see this post from a developer.
Music: sounds arranged such that they construct feelings.

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #7
Frame or block size doesn't necessarily equal latency. FLAC encoder and decoders do indeed process one block at a time, having a latency of one block, but that isn't necessarily the case for other formats. One could also create a format that can be encoded and decoded on the fly, while reading/writing the block. That seems to be possible with TTA, see this post from a developer.

With my ignorance on the matter, this might be a big miss - or there could be something to it:
I just corrupted some lossless files to test error handling, and while codecs with error handling drop the entire frame/block, it seems that TTA might - if the bit flip occurs late in the block - read its way far into it before static'ing out. At worst, TTA would corrupt nearly a second (= a block size); but I also got it down to a few hundred samples. So for what it is worth, it means it doesn't have to read it all to decode it.

At first glance, ffmpeg's TAK decoder narrowed down the faulty interval by 80 percent (takc.exe dropped around .25, ffmpeg got down to .05 seconds loss), so I don't want to bet too much on my unqualified speculations.
EDIT: Huh, ffmpeg's flac decoder does the same. One test: got it down from 8192 to 86 samples. And ffmpeg's WavPack!
(But, ffmpeg's TTA decoder drops a whole second!)

 

Re: MAC (APE) lack of streaming feature - what does it mean?

Reply #8
That isn't streaming, you're just loading the file from your network drive, so doesn't apply to you. 

To kinda repeat myself, there is a question of what end-users should worry about.

Do any of those squeezeboxes and later smart-home-playing solutions employ streaming in this sense? 
Honest question, so to further expose my ignorance here: would it be so that those who do employ streaming, have a fixed set of codecs supported - i.e. Monkey's users will just see that they cannot get Monkey's with this? Because unless they intend to hack support into it, they probably would want to know whether rather than why not.