Youtube audio bitrate

[bxyhxyh]

Maximum AAC bitrate of youtube's audio was 192 kbps. And it was only for 720p videos.
Maximum vorbis/opus bitrate was around 170 kbps.

AAC 128 kbps for 480p, 720p60, 1080p or bigger
AAC 96 kbps for 360p

With "Complete Youtube Saver" plugin for Firefox and "YouTube™ Downloader Lite" plugin for Opera, I can download audios without downloading whole video unless it's not DASH videos which 720p isn't, so I have to download the video to get 192 kbps audio.

But recently when I download 720p videos, it's no longer 192 kbps. They're all same 128 kbps.
I guess they thought that using 128 kbps for 2160p and 192 kbps for 720p is too unfair?

Is it same 128 kbps for you?

[sneaker_ger]

I have seen this as well. It says "192 kbps" for the non-DASH-720p-MP4 stream but it is actually the same audio as the DASH m4a "128 kpbs" stream.

[bxyhxyh]

Even though bitrates are the same 128 kbps, audio specters are bit different for DASH and non-DASH videos.
What a waste of computing power.

It seems best quality audio we can get from youtube is OPUS 170 kbps.

[sneaker_ger]

Even though bitrates are the same 128 kbps, audio specters are bit different for DASH and non-DASH videos.
In my tests they are bit-identical. (except DASH stream has some extra trailing frames)

[bxyhxyh]

I tried these two videos.
"Introducing Handle", #4 on trending
Other one is this https://www.youtube.com/watch?v=iGOFEK5EOj8
checked with spek

[sneaker_ger]

bit-identical

[LoRd_MuldeR]

I think this also depends on how you define/determine the "bitrate" of an AAC stream. Unlike MP3, AAC does not use fixed-size frames. AAC frames can be pretty much any size in bytes.

Even a "CBR" AAC stream can use varying frame sizes, as long as the derivation from the "mean bitrate" is kept within certain bounds. And if the stream is not supposed to classify as "CBR", there is no real limitation at all.

AFAIK, the ADTS format, which is the format commonly used to store "raw" AAC streams, does not even have a "bitrate" field; only a "frame_length" field, for each individual frame.

With MP4 container or DASH, you probably have some "nominal" audio bitrate specified in the header (e.g. 128 or 192 kbps), but there is no guarantee that this matches the stream's actual average audio bitrate...

[bxyhxyh]

This has 192 kbps audio.
https://www.youtube.com/watch?v=jikDkFCoGF0

So, some videos have 192 kbps audio...

[poisondeathray]

This has 192 kbps audio.
https://www.youtube.com/watch?v=jikDkFCoGF0

So, some videos have 192 kbps audio...

That 720p video doesn't actually have 192kbps audio

[bxyhxyh]

What?
But it says
General
Complete name : C:\Users\BallGNM\Desktop\8 Beat Stereo\Battletoads & Double Dragon [Complete OST] (Music of Snes HQ).mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/mp42)
File size : 68.5 MiB
Duration : 15 min 45 s
Overall bit rate mode : Variable
Overall bit rate : 608 kb/s
Encoded date : UTC 2014-06-23 22:51:00
Tagged date : UTC 2014-06-23 22:51:00
gsst : 0
gstd : 945330

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=60
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 15 min 45 s
Bit rate : 413 kb/s
Maximum bit rate : 4 317 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.015
Stream size : 46.5 MiB (68%)
Tagged date : UTC 2014-06-23 22:51:11

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 15 min 45 s
Bit rate mode : Variable
Bit rate : 192 kb/s
Maximum bit rate : 202 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 spf)
Compression mode : Lossy
Stream size : 21.6 MiB (32%)
Title : IsoMedia File Produced by Google, 5-11-2011
Encoded date : UTC 2014-06-23 22:51:05
Tagged date : UTC 2014-06-23 22:51:11

Now I'm confused.

[poisondeathray]

Well that's interesting, isn't it?

It looks like different 720p versions

I used IDM to download


General
Complete name : F:\_DOWNLOADS\Battletoads & Double Dragon [Complete OST] (Music of Snes HQ).mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 26.0 MiB
Duration : 15 min
Overall bit rate mode : Variable
Overall bit rate : 230 kb/s
Encoded date : UTC 2017-02-23 15:45:15
Tagged date : UTC 2017-02-23 15:45:15

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 15 min
Bit rate : 102 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.004
Stream size : 11.5 MiB (44%)
Title : ISO Media file produced by Google Inc.
Encoded date : UTC 2017-02-23 15:45:15
Tagged date : UTC 2017-02-23 15:45:15
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 15 min
Bit rate mode : Variable
Bit rate : 126 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 spf)
Compression mode : Lossy
Stream size : 14.2 MiB (55%)
Default : Yes
Alternate group : 1
Encoded date : UTC 2014-06-23 22:45:49
Tagged date : UTC 2014-06-23 22:45:49

[poisondeathray]

jdownloader picked the same version as you, 192kbps audio, 68.4MB filesize

youtube-dl got the smaller version, 128kbps audio

So my bad...

jdownloader can download the 192kbps m4a audio track separately (21.7MB)

[bxyhxyh]

Have you tried different videos with jdownloader?
From videos I've downloaded with plugins I've mentioned in the first post, only this one had 192 kbps audio.

[poisondeathray]

Have you tried different videos with jdownloader?
From videos I've downloaded with plugins I've mentioned in the first post, only this one had 192 kbps audio.

Not yet,

But you're looking for "recent" upload, maybe 2017, end of 2016 video , right ? Looking for evidence that youtube might use 192kbps aac for some videos recently ?

It can download 192kbps audio from your earlier post #5 too, but that was uploaded 2013, that more recent one was uploaded in 2014

[poisondeathray]

Here is a "recent" trailer (King Kong) where it supposedly gets 192kbps audio m4a separately . Date uploaded Feb 17,2017

https://www.youtube.com/watch?v=7-zYoocu2Jo

But I actually downloaded it and it's 128kbps, same as the 1080p video . Those older 2013, 2014 examples were actual 192kbps

[bxyhxyh]

I've tried this https://www.youtube.com/watch?v=-7xvqQeoA8c and this https://www.youtube.com/watch?v=pzYseKMQ1oU. And they were 128 kbps (126 actually, but that's not the point.)

[poisondeathray]

So it looks like only older uploaded videos ... jdownloader "says" 192kbps audio separately for that first one "Handle", but downloading it is actually 126kbps

[bxyhxyh]

How is this? Sorry if i'm being annoying (I don't want to download another downloader, so I'm asking)
https://www.youtube.com/watch?v=1x3D4z89Em0
It was 192 kbps a year ago. Now it's 126 for me.

[poisondeathray]

How is this? Sorry if i'm being annoying (I don't want to download another downloader, so I'm asking)
https://www.youtube.com/watch?v=1x3D4z89Em0
It was 192 kbps a year ago. Now it's 126 for me.

Reported as 192kbps, but actual download 126kbps. That was uploaded Oct 2015


Are you saying, at one point you received actual 192kbps ?

[bxyhxyh]

Yeah, I still have audio file extracted from that. General
Complete name : F:\fromcrasheddisk\music\Jackal (MOTHER BRAIN! cover).aac
Format : ADTS
Format/Info : Audio Data Transport Stream
File size : 9.38 MiB
Overall bit rate mode : Variable

Audio
Format : AAC
Format/Info : Advanced Audio Codec
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
Frame rate : 43.066 FPS (1024 spf)
Compression mode : Lossy
Stream size : 9.38 MiB (100%)


126 kbps one has 5 mb filesize

What a random...

Edit:
Oh mediainfo written here didn't include bitrate.
But video I downloaded now is 8.5 mb. Even smaller than extracted audio.

[sneaker_ger]

But I actually downloaded it and it's 128kbps, same as the 1080p video
Resolutions >720p never include audio. Those are separate DASH streams.

[poisondeathray]

jdownloader picked the same version as you, 192kbps audio, 68.4MB filesize

youtube-dl got the smaller version, 128kbps audio

So my bad...

jdownloader can download the 192kbps m4a audio track separately (21.7MB)



And now, a few hours later, that version is no longer available!! or at least jdownloader can no longer pick it up!

But I still have it saved to my HDD , both the 720p vid+audio and audio separately downloaded - so it's real

maybe they are clearing out the older higher bitrate audio versions