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Topic: Best YouTube's audio (Read 5764 times) previous topic - next topic
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Best YouTube's audio

I know the limitations of YouTube, but some songs have no other sources.

In the past, I downloaded one video at best quality available.

Audio information by MPC:
Format/Info: Advanced Audio Codec (AAC)
Format version: Version 4
Format profile: LC
Bit rate mode: Variable
Channel(s): 2 channels
Channel positions: Front: L R
Sampling rate: 44.1 KHz
Compression mode: Lossy
Stream size: 8.73 MiB (100%)

Recently, I discovered that now YouTube permits download only the audio (directly from YouTube, no third-party), so I downloaded the same sound by this different way.

Information by MPC:
Format/Info: Advanced Audio Codec (AAC)
Format profile: LC
Codec ID: 40
Duration: 10mn 37s
Bit rate mode: Constant
Bit rate: 254 Kbps
Channel(s): 2 channels
Channel positions: Front: L R
Sampling rate: 44.1 KHz
Compression mode: Lossy
Stream size: 19.3 MiB (99%)
Encoded date: UTC 2013-07-21 16:59:07
Tagged date: UTC 2013-07-21 16:59:07

Based on "encoded date" (the video was uploaded in 2009), I guess this is reencoding from my first file. So, although the higher bitrate of the new file, I think the old file have better quality because it is more original/less modified".

Am I right?

Best YouTube's audio

Reply #3 –
I *think* everything you get from youtube is transcoded, or at least everything that isn't in the exact format they expect.

If you're concerned though, you could test by uploading audio and then downloading it.

Best YouTube's audio

Reply #4 –
Quote from: saratoga on
everything you get from youtube is transcoded,


Correct. I know it.

I doubt that YouTube have the backup from original upload, then the new audio-only file must be transcode from FLV/MP4/WebM YouTube's video. New lossy encoding will always poorer than source, so I think the first file (8.73 MiB AAC) is better than recent file (19.3 MiB AAC). But I'm not sure...

Best YouTube's audio

Reply #5 –
But why are you assuming they didn't just create all the transcodes from the source when it was uploaded?

Best YouTube's audio

Reply #6 –
Thanks for the link sintapilogo. I actually thought there was an official way from YouTube, I think this is illegal...like all the other very similar extensions Google already blocked.

Best YouTube's audio

Reply #7 –
I want try this,thanks

Best YouTube's audio

Reply #8 –
Quote from: eahm on
I think this is illegal...like all the other very similar extensions Google already blocked.
Most likely. And as per #9 of the Terms of Service, Hydrogenaudio does not exist to help people collect tips on how to leech data in a form that is not explicitly permitted by the original supplier, especially considering that a majority of the data from this source will be copyrighted.

Best YouTube's audio

Reply #9 –
Quote from: db1989 on
And as per #9 of the Terms of Service, Hydrogenaudio does not exist to help people collect tips on how to leech data in a form that is not explicitly permitted by the original supplier, especially considering that a majority of the data from this source will be copyrighted.


Hmm, sorry, thanks for remove the links.

But the thread's discussion can continue, right?

Best YouTube's audio

Reply #10 –
Quote from: sintapilgo on
So, although the higher bitrate of the new file, I think the old file have better quality because it is more original/less modified".

Am I right?


Did you try a ABX test?

Also, a spectrum analysis might reveal a few things without the need for a BX test.

If I where to take a wild guess I'd say that Youtube (for both audio and video) uses a intermediary format to store a "master", this may or may not be lossy or very high bitrate lossless.
It is also possible that Youtube do keep the original uploads if they are within certain desired parameters of their automation system. Search the net and see if you find any info about their process.

One thing I feel somewhat confident about is that Youtube most likely does not upconvert anything. I.e. going from low bitrate to a higher would be silly and potentially degrade the audio.
It would also be a bad utilization of bandwidth.

Now this is original uploads we're talking about. When it comes to mashups etc. then some people use youtube videos as their sources and then upload to youtube again, what's happen to the video or audio at that point is anyone's guess, but depending on the lossy formats bitrates it wont take many rounds of that before you start hearing artifacts.

I did some uploads where the audio was lossless (uncompressed PCM), my guess is that those are stored at youtube's servers someplace as FLAC or (something else lossless).

Youtube should provide you with the best quality it can at the bitrate it gives you. So 360p is more lossy than a 1080p stream for example. (the audio follows suit as well).

I have seen some Streams that never are above 360p or 480p, it is possible the original upload was never better than that, hence no 720p for example. I'm guessing the same is true with the audio in that regard.
I.e: Garbage In = Garbage Out

Best YouTube's audio

Reply #11 –
Quote from: sintapilgo on
Quote from: db1989 on
And as per #9 of the Terms of Service, Hydrogenaudio does not exist to help people collect tips on how to leech data in a form that is not explicitly permitted by the original supplier, especially considering that a majority of the data from this source will be copyrighted.


Hmm, sorry, thanks for remove the links.

But the thread's discussion can continue, right?

Right, though you should have asked if you weren't sure about TOS #9.  This is especially the case considering that when a member asked you for the source of your claim, you took it as an opportunity to break the rule.

Consider yourself lucky for not being banned from the forum.  Next violation of TOS #9 will result in a permanent ban.

Best YouTube's audio

Reply #12 –
Quote from: Rescator on
Did you try a ABX test?


My current headphone isn't so accurate, I can't hear the difference.

It is a theoretical question.


Quote from: Rescator on
Also, a spectrum analysis might reveal a few things without the need for a BX test.


The new audio file uses an uncommon codec and I don't know about these technical methods. =/


Quote from: Rescator on
One thing I feel somewhat confident about is that Youtube most likely does not upconvert anything.


I'm sure they upconvert, I've already tested with other file:

Size: 8.23 MiB (original) < 10.6 MiB (YT)
Video (MP4) bitrate: 278 Kbps (original) < 335 Kbps (YT)
Audio (AAC) bitrate: 61.7 Kbps (original) < 96.0 Kbps (YT)

Best YouTube's audio

Reply #13 –
Quote from: sintapilgo on
Quote from: Rescator on
Did you try a ABX test?


My current headphone isn't so accurate, I can't hear the difference.


Its debatable if more accurate headphones make it easier or harder to hear a difference.  Some people say easier, so I would not assume harder as you seem to.

Quote from: sintapilgo on
It is a theoretical question.


I think theory is pointless here unless you can find out for sure what youtube does.  If you're just guessing how they transcode, theory is only as good as your guess. 

Probably better to test.
 

Best YouTube's audio

Reply #14 –
Quote from: saratoga on
But why are you assuming they didn't just create all the transcodes from the source when it was uploaded?


From the audio-only file: "Encoded date: UTC 2013-07-21 16:59:07"

The upload was done years ago...




Quote from: saratoga on
I think theory is pointless here unless you can find out for sure what youtube does.  If you're just guessing how they transcode, theory is only as good as your guess.


Maybe someone could recommend a software that analyze if the 254 Kbps is a compression or bloated from smaller bitrate.