Hi All,
I am trying to create a few video files for testing of a bug in the implementation of the XBox One's audio subsystem.
https://forums.whirlpool.net.au/forum-replies.cfm?t=2239812
So I would like to make some test videos which can be played back on the XBox One via Plex media centre or equivalent. I would also like to play them back on a range of other devices like a PS4, chromecast etc...
I want to make them something like this
https://www.youtube.com/watch?v=zYfqaWSZiuk
However obviously I can't upload anything greater than 2 tracks to youtube as I don't think it supports it. So I was just going to convert into an mp4 and play back by streaming to the XBox One.
So I would have each of the speech events go to the relevant surround channel/speaker.
I was then going to have white noise play for 3 seconds on each channel one by one in a circle moving from
7.1 channel - left front -> centre -> right front -> right surround -> right surround rear -> left surround rear -> left surround
5.1 channel - left front -> centre -> right front -> right surround -> left surround
Pro logic II - left front -> centre -> right front -> right surround -> left surround
I made the audio files
http://www.phoenixdigital.com/surround/full-male.mp3
http://www.phoenixdigital.com/surround/full-female.mp3
I pulled them into Audacity and followed these steps but didn't really get anything useful. I made flacs and wavs but nothing seemed to work.
http://manual.audacityteam.org/o/man/advanced_mixing_options.html
Nothing came out of the surround speakers even when I tried various combinations of where to put the channels
http://en.wikipedia.org/wiki/Surround_sound#Standard_speaker_channels
One of the many configurations I tried.
http://imgur.com/a/eMNGw
I then mixed them into various combinations but nothing seemed to work when played back on the amp.
http://www.phoenixdigital.com/surround/surround-7-1-test.flac
Does anyone have any suggestions for any opensource software that can help or to steer me where I am going wrong? I am only trying to make some test files so don't really want to fork out any cash.
I also tried to mix this audio into a single picture video using avidemux and got pretty crap results too with nothing working.
http://www.phoenixdigital.com/surround/TestVideo.mp4
http://www.phoenixdigital.com/surround/TestVideo-2.mp4
Excuse the cat I just went with the first picture I found and was not expecting to put it up publicly.
Ideally when I get this working I would love to have the following video files
- MP4 Container video with 7.1 DTS Audio
- MP4 Container video with 7.1 Dolby Digital Audio
- MP4 Container video with 5.1 DTS Audio
- MP4 Container video with 5.1 Dolby Digital Audio
- MP4 Container video with Prologic II audio
The video image can just be a static image displaying what format the audio tracks are in.
Can anybody steer me in the right direction please?
I even wouldn't mind extending this further by playing the sounds on simultaneously on diagonal speakers to see how the pro logic II handles this.
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Well, right off the bat, I'd say you didn't really create a true "mp3 surround". That requires use of a proprietary codec, which it doesn't sound like you used. Standard mp3 doesn't support true discreet surround, and many of the MS/Intensity/Joint stereo features DESTROY the interchannel phasing that is necessary for DS/PL/PL2 to work, especially at anything but the highest bitrates. Heck, even full Stereo/DualMono encoding can't always retain what's necessary.
Next, that suggested mixdown method is way too crude to attempt an emulation of dolby surround, much less PL or PL2. You need a real PL/PL2 encoder. I have used Surcode (for years). $$
Sources for this are best taken from multichannel WAVs (or alternately, multiple single-channel WAVs).
Scott -
I did make multi channel flacs and wavs as linked in the original post. It was only the source of the text to speech that was mp3.
http://www.phoenixdigital.com/surround/surround-7-1-test.flac
http://www.phoenixdigital.com/surround/full-male.wav
These didn't seem to play on the right channels though.
I had seen surcode but can't really justify spending $100 to identify a bug in M$ console.
I was hoping to use something like AC3 Filter to do 5.1 -> pro logic II (see last post here) but need to generate the 5.1 version first.
http://superuser.com/questions/242229/downmix-surround-to-dolby-pro-logic-at-the-os-dr...l-in-windows-7
It wont be 100% perfect but should be close enough to reveal the bug in the XBox One sound subsystems.
If Dolby Digital or DTS is not possible without proprietary codecs is there a non proprietary format that will allow 5.1 and 7.1 encoding? -
I'd appreciate it if you could. Happy to wait there is no urgency.
This bug has been on the XBox One for over a year and MS engineers don't seem that interested in fixing it.
I was hoping some simple example videos of 7.1, 5.1 and Pro Logic II would shed some light on the issue for people who don't understand how important surround sound is. It might also expose some other flaws in their sound subsystems. -
Here are the two multi channel wav files
http://www.phoenixdigital.com/surround/surround-7-1-test.wav
http://www.phoenixdigital.com/surround/surround-5-1-test.wav
With the 5.1 wav file obviously also used to make the Pro Logic II version as well. -
What makes you think it's a bug in the sound system?
Surround audio is supported and can be tested using a DVD or Blu-Ray. If it's only occurring with mp4 playback, it could be an app/playback tool issue.Google is your Friend -
Sigh. Here we go again. I will explain this for about the 20th time. No offence to you directly but it is getting old explaining this as so many people can't seem to grasp this issue. Primarily because the knowledge of how Dolby Pro Logic works has been lost in the last few decades. I Just had a massive back and forth on those whirlpool forums with someone who believed that Pro logic was purely a simulated surround process that did not involve encoding at all.
First of all why can't I test a bluray or DVD?
If you can direct me to a simple test DVD/Bluray which has a simple test that specifically plays back sound from each channel at a specified time that would be great. Just putting in any movie sure I might hear things from the surround but how do I know the sounds are coming from the correct surrounds?
Secondly it is the sound system because this occurs on a huge range of apps within the XBox One.
- Hulu Plus
- Netflix
- TV
- Video
- Youtube
The issue in a nutshell is this
If you send 5.1, 7.1 or Bitstream data to most amplifiers (every one I have and others have tested) The amplifier will only output those channels of data. There is absolutely zero chance of you changing the settings on the amp to use Dolby Pro Logic.
This is great for DVDs, Blurays and games that utilise more anything more than 2 channels.
Where this breaks is when the content you are watching is a 2 channel audio stream which has a pro logic encoded signal. In this instance the Xbox sends 5.1 or 7.1 channels to the amp. All of these channels are silent apart from the L+R channel. That is great and what you would expect it to do. The problem is that amps see the 5.1 or 7.1 channels and will just push the sounds out of the left and right speakers. There is no way to tell it that this should be decoded by pro logic decoder. No amp for the last 20 years has EVER allowed this.
So the XBox is breaking the ability for ANY pro logic encoded content to work. No other device has ever had this issue. Even the TiVo which injects it's own audio into the playback content stream is smart enough to know "Do not send any more channels than are in the content you are playing back"
If you want more information and tests to show the bug read the mega thread of it here.
http://forums.whirlpool.net.au/forum-replies.cfm?t=2239812&p=2#r24
I'm happy to answer a few basic questions that are not covered there but explaining this issue every month is getting really really old.
I want these test files created to have a consistent repeatable test so that when people say "prove it" I don't believe you they can do it themselves without me needing to make anohter post like this.
I get repeated calls from people saying "How do you know this is pro logic encoded content?"
FWIW as far as I can tell from all the reading I have been doing to "prove" this to non believers. It is extremely hard for distinct sound to be decoded to the rear surrounds by accident on the pro logic decoder. If you are playing back two channel content from ANY device through an amp set to pro logic and there is distinct sound coming from the rear speakers then it is highly likely the content is pro logic content. Unless the sound editor was doing something funky with phasing between the left and right channels there is no way sounds should ever come from the rear speakers.
I found this article yesterday stating the same
http://www.documentary.org/feature/sound-advice-how-ensure-your-audio-playback-comes-t...loud-and-clear
mono - single channel of audio
Lo/Ro - two audio channels not encoded with any surround content
Lt/Rt - two audio channels encoded with 4 channels of sound via pro logic encoding.
Our standard processor setting at Sundance is Dolby Pro Logic and is changed only if we have a problem tape.
With that said, we play back all of our non-digital soundtrack from video back as Dolby Pro Logic. If the track is mono, it will play back as mono. If it is Lo/Ro, it plays back that way, or if it is Lt/Rt, it will playback as 4.0 analogue stereo.
So yeah I specifically want the
- 5.1 pro logic encoded surround mp4 to have a simple test for people to show this issue
I want the other mp4s to further test the Xbox One's audio subsystems
- 5.1 Dolby Digital encoded mp4
- 5.1 DTS encoded mp4
- 7.1 Dolby Digital encoded mp4
- 7.1 DTS encoded mp4
These other video files will also show the impact of certain settings on the XBox one further break any two channel pro logic content playback.Last edited by phoenixdigital; 13th May 2015 at 16:53.
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Further to my point above the biggest reason why this has not been noticed by people is they have been watching TV and content on their amps wrong for the last two decades.
People have forgotten what Dolby Pro Logic is and what it was designed for. They just think it's some sort of fake surround sound.
It's not and most of the content I have come across on TV actually appears to be Pro Logic encoded content.
If you are playing 2 channel audio tv shows back on your amp and have your amp set to only output it on the left and right speakers you are likely doing it wrong. You are missing out on hearing the show as the director or sound editor intended.
Cornucopia are you a professional sound mixer? Can you confirm if pro logic is still in use much today?
In what situations do you encode pro logic content? -
@phoenixdigital, got a lot to discuss...
1st, you have a mix of accurate and misleading info regarding DS/PL/PL2.
Those are MATRIXED types of surround, as opposed to DISCREET types of surround like 5.1AC-3 or DTS. Matrixed surround folds-in/mixes-down mutliple channels into a smaller subset, and then upon playback attempts to remix-up/unfold back to the original surround channels. Note however, it is mathematically impossible to fully & accurately recover the originals. Once folded-in, the signals are for all intents and purposes just a standard stereo channel pair: it is only the intricate phase/delay/amplitude differences that help indicate and guide the decoder to guessing the constituency of the resulting channels.
But, there are plenty of true, standard stereo files that also naturally exhibit some of those same difference cues and create a "false surround positive". There are also some combinations of sounds that, when combined, cancel each other enough to the point that accurate surround cues are destroyed, creating a "false surround negative". IOW, it's a very inexact science.
Next, you need to understand triggering.
With ANALOG versions of DS/PL/PL2, there is nothing about the signal or header or metadata that flags a decoder to tell it to engage and decode to surround. This must be engaged manually, and this is often where you can get your false positives and false negatives (including the false stereo negative, where a surround-encoded signal is never decoded and is just presented as stereo).
Digital files and streams, however, may have the benefit of providing for a flag as to the nature of the signal. DD (aka AC-3) has such a flag (assuming it is set correctly during encode - a big if). There is no such flag for WAV/AIFF/LPCM (it could be added to extra user-data headers, but there is no consensus for its use). So, even for digital, with the exception of AC-3*, you are left with the decoder guessing as to the nature of the signal (matrixed surround? or just plain stereo?).
Next, you need to understand how digital surround files/streams (true discreet types) interact with decoders.
It can happen within a PC, where the decoder is called from the app after the surround file/stream is read. Then, it decodes to multiple channels and outputs 5/6 full separate channels (either analog multiple cables, or digital via hdmi) to amp/speakers.
Alternately, in a PC (or settop), the decoder is told to be bypassed and passed-through to the analog or digital connection. If analog, very often the decoder is able to do a live mixdown of 5.1 to DS/PL/PL2, however this will suffer the same identity vagueness that all those other analog signals do.
If digital, the original raw surround stream can be passed along via HDMI to be decoded at the amp (assuming it is capable of decoding that format), or it might be passed along via SPDIF.
If SPDIF, that cabling format does NOT allow for full discreet multichannel data (doesn't support that high of a bandwidth), so LPCM multichannel has to try a different tactic...but compressed multichannel bitstreams (such as AC-3, DTS) are able to be encapsulated within the bandwidth requirements of the SPDIF format (which was originally only designed for stereo). As encapsulated, they have certain bitstream type signatures that allow decoders at the amp to recognize them for what they are and decompress and decode them properly to their LPCM multichannel destinations. So this last scenario is the most common one, and works quite nicely & automatically. HDMI will probably soon overtake it in popularity, but only after amps/receivers get replaced (which cycle is much slower than for other devices).
Notice that those all dealt with true discreet digital surround streams. They are the one scenario (barring AC-3 flagging), where surround decoding is automatically engaged at the amp. And if an AC-3 2.0 stream is flagged with DS encoding, amps which already can decode AC-3 (coming through the SPDIF or HDMI) should also be able to auto engage DS/PL/PL2 decoding. But those are really the only possible methods where this works, start-to-finish.
Next, you need to not make assumptions about content vs. surround, just like the decoder should not.
As I've already said (and was re-iterated in that link), there is no way for analog Lt/Rt to be flagged separately from Lo/Ro. Given one of each, you'll always have one of them decoded incorrectly. DS decoder always Engaged=Lt/Rt ok, Lo/Ro is "faked" surround with weird shifts. DS decoder always Disengaged=Lt/Rt as stereo (with possible echoey/phasey elements), but Lo/Ro ok.
And the only way to PROVE IT is with AC-3 2.0 digital stream with flagging.
BTW, there was an inaccuracy in that link (which I think was a journalistic error/misquote, not a falsehood on the part of the sound engineer): the quote cited in your post above says "with DS engaged, Lo/Ro will play back as Lo/Ro", but they also said earlier that there could be phase issues in the Lo/Ro which confuse the decoder. Of course, they blame other "lesser adept" engineers, but I would blame the content. Almost any LEGIT binaural or ambisonic recording, and many ORTF recordings would have enough "interesting" phasing to make a DS decoder do bizarre things. Unfortunately, their response to this is a "drop it down to mono and maybe we'll work it out later" blowoff move, which I wouldn't tolerate.
Next, I don't know where you are getting this "can't change DS on amps" stuff, but I have both an older Yamaha surround amp, and a slightly newer/better (but not yet HDMI, HD-audio-capable) Onkyo surround amp. Both of them allow a great deal of options, both in the engaging/disengaging of DS/PL/PL2, but also in adjustment of the settings (surround ch. delay, subwoofer on/off, which mode, etc). And I am confident that most of the surround amps from the last decade are similarly configured.
Yes, they could be misconfigured in users' homes, but not necessarily. Mine arent'.
Next, you are correct in stating DS/PL/PL2 are not "fake" surround. Usually. I have already mentioned it is possible to create false positives. But also, even so, DS/PL/PL2 and in fact ANY matrixed surround scheme (QS, SQ, Circle Surround...) is doomed to be incomplete, muddy, quasi-surround. By very nature of it being matrixed. Again, completely accurate extraction is mathematically impossible, otherwise you could get "something out of nothing".
Next, YES, I am/was a professional sound editor/mixer (though I haven't done much very recently), among other multimedia skills.
Yes, I have used the professional Dolby encoders & decoders, not just Surcode, and not just freeware, reverse-engineered knockoffs.
Does DS/PL/PL2 still get encoded onto 2ch audio tracks even today? Yes. More than your detractors are saying, but probably much less than you are envisioning.
Somewhere back in you post, you mentioned creation of a 5.1 channel digital file/stream where all but the front 2 channels were empty/silent, but that those 2 were encoded in DS/PL/PL2. THIS WOULD/SHOULD NOT HAPPEN. It is a misuse of the format. If one had a multichannel stream, ALL decoders would treat it as such and map its outputs accordingly, bypassing any DS/PL/PL2 decoding (which by its very nature must operate on only 2 source channels, not "2 from among xx"). It is also a waste of the multichannel stream's bandwidth: why not just put the tracks where they belong (which are already there waiting for them)? This is never considered even close to a standard/best practice.
What you might be confusing this with is the COMMON practice of using an 8 channel file/stream to incorporate both the discreet 5.1/6 channel surround mix (tracks 1...6) as well as a pre-mixed 2 channel (tracks 7, 8) mixdown (whether Lo/Ro or Lt/Rt, optional), with the playback environment to decide which group of the two is the best to use. In fact many/most pro masters are distributed this exact way. This is similar to the cited link where 4channel DigiBeta or HDCam masters use Lo/Ro for Ch1, Ch2 and Dolby E (a pro variant of AC-3, utilizing 5.1 surround) compressed digital data spread across Channels 3 & 4.
***********
Hope that clears some things up.
I hope to have some files for you tomorrow, though I just found out one of my mediaserver's HDDs S.M.A.R.T. indicators is flagging a suspect drive, so I might have to do a little precautionary data backup/juggling first.
Scott
*Just checked, QT/MOV has no facility for Lt/Rt flagging, nor MP4/AAC, nor MP2, MP3, Opus. CAF has explicit (though obscured) support for Lt/Rt flagging. Flac doesn't currently, but has specific reserved areas where this could be added, same with MKV/MKA. DTS, being the direct competitor to Dolby, would probably NEVER add it.Last edited by Cornucopia; 14th May 2015 at 02:32.
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Let me start by saying thank you very much for the incredibly informative post.
Yep I was aware that Pro Logic was a matrixed format (not discrete) and absolutely understand it is mathematically impossible for the decoding method to be perfect.
It is however a good enough format to use if the broadcaster only wants to send 2 channels in my personal opinion. I would prefer some form of surround than just left and right channels.
I would not however want "faked" simluated surround that some amps offer.
Next, you need to understand triggering.
With ANALOG versions of DS/PL/PL2, there is nothing about the signal or header or metadata that flags a decoder to tell it to engage and decode to surround.
Unlike digital discrete digital signals which can contain flags and other data.
Next, you need to understand how digital surround files/streams (true discreet types) interact with decoders.
They are the one scenario (barring AC-3 flagging), where surround decoding is automatically engaged at the amp. And if an AC-3 2.0 stream is flagged with DS encoding, amps which already can decode AC-3 (coming through the SPDIF or HDMI) should also be able to auto engage DS/PL/PL2 decoding. But those are really the only possible methods where this works, start-to-finish.
So there are 5 settings on the XBox one for Audio out- Uncompressed Stereo - I can change the decoding options on the amp
- 5.1 Uncompressed - I cannot change the surround settings on the amp.
- 7.1 Uncompressed - I cannot change the surround settings on the amp
- Bitstream Dolby - I cannot change the surround settings on the amp
- Bitstream DTS - I cannot change the surround settings on the amp
I have a Yamaha Receiver-RX-V775.
I'll do more tests when I get back home next week.
Next, I don't know where you are getting this "can't change DS on amps" stuff, but I have both an older Yamaha surround amp, and a slightly newer/better (but not yet HDMI, HD-audio-capable) Onkyo surround amp.
I'll post back the format when I get to test it.
Next, you are correct in stating DS/PL/PL2 are not "fake" surround. Usually. I have already mentioned it is possible to create false positives. But also, even so, DS/PL/PL2 and in fact ANY matrixed surround scheme (QS, SQ, Circle Surround...) is doomed to be incomplete, muddy, quasi-surround. By very nature of it being matrixed. Again, completely accurate extraction is mathematically impossible, otherwise you could get "something out of nothing".
Would it be correct to say that if you listened to a show while the amp is on Dolby Pro Logic that if you hear discrete sounds from the surrounds then it was likely matrixed with a pro logic encoder? I'm taking obvious sounds like birds chirping, water running or trees rustling. Not muffled, garbled or accidental false positive surround signals.
Next, YES, I am/was a professional sound editor/mixer (though I haven't done much very recently), among other multimedia skills.
Yes, I have used the professional Dolby encoders & decoders, not just Surcode, and not just freeware, reverse-engineered knockoffs.
Does DS/PL/PL2 still get encoded onto 2ch audio tracks even today? Yes. More than your detractors are saying, but probably much less than you are envisioning.
Somewhere back in you post, you mentioned creation of a 5.1 channel digital file/stream where all but the front 2 channels were empty/silent, but that those 2 were encoded in DS/PL/PL2. THIS WOULD/SHOULD NOT HAPPEN. It is a misuse of the format. If one had a multichannel stream, ALL decoders would treat it as such and map its outputs accordingly, bypassing any DS/PL/PL2 decoding (which by its very nature must operate on only 2 source channels, not "2 from among xx"). It is also a waste of the multichannel stream's bandwidth: why not just put the tracks where they belong (which are already there waiting for them)? This is never considered even close to a standard/best practice.
I have posted in many places trying to get some traction that this is an issue and I have encountered some seriously agro hate and ignorance from people who think Dolby Pro Logic is a fake surround simulation.
So the XBox One engineers thought in their brilliance "lets control the sound system completely because the user might want to run two apps at a time like playing a game while also chatting to someone on skype". So they will need to mix the audio from these two apps before it is sent to the amp.
Great idea and brilliant concept. However this is where it falls down.
So I mentioned there were 5 settings on the XBox One.
If I am playing back something from Netflix, Hulu Plus, Youtube or the TV and that content only has two channels (possibly pro logic matrixed encoded). This is the resulting output which goes to my amp.
- Uncompressed Stereo - Two channels sent to the amp and I have full control of surround format from the amp.
- 5.1 Uncompressed - 5.1 channels sent to the amp with audio content only on the L+R channels the rest silent. I am locked out of changing surround on the amp.
- 7.1 Uncompressed - 7.1 channels sent to the amp with audio content only on the L+R channels the rest silent. I am locked out of changing surround on the amp.
- Bitstream Dolby - 5.1 channels sent to the amp with audio content only on the L+R channels the rest silent. I am locked out of changing surround on the amp.
- Bitstream DTS - 5.1 channels sent to the amp with audio content only on the L+R channels the rest silent. I am locked out of changing surround on the amp.
Now you can see my pain. In order to watch Po Logic content I need to change my XBox settings to "Uncompressed Stereo". Then if I want to play a game or Bluray to experience full digital surround I have to change to one of the other settings.
Microsoft have a broken sound subsystem.
This has to be one of the biggest first world problems of this decade I would think
Hope that clears some things up.
I hope to have some files for you tomorrow, though I just found out one of my mediaserver's HDDs S.M.A.R.T. indicators is flagging a suspect drive, so I might have to do a little precautionary data backup/juggling first.
Also as for why I want so many formats. I want to see if there is anything else broken in the XBox Ones sound subsystems.
Obviously I know what will happen with the Pro Logic one when on 5.1, 7.1 and Bitstream XBox One setting. It will be broken as I described.
What I am curious about is.
Does the XBox One play the 5.1 sound correctly when on the 5.1 setting?
Does the XBox One play the 7.1 sound correctly when on the 7.1 setting?
Does the XBox One play the 5.1 and 7.1 sound correctly when on the bitstream setting?
How does the XBox One downmix the 7.1 video file if I am on the 5.1 setting?
How does the XBox One downmix the 5.1 video file if I am on the Uncompressed Stereo setting?
How does the XBox One downmix the 7.1 video file if I am on the Uncompressed Stereo setting?
How does the XBox One upmix the 5.1 video file if I am on the 7.1 setting?
Does it behave differently for DTS or Dolby encoded digital signals.Last edited by phoenixdigital; 14th May 2015 at 05:10.
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More tomorrow. But, how is your Xbox connected to your amp? Spdif/TOSlink (coax or optical)? Or HDMI? Or Analog? I think I might know the reason behind your assumed limitations, and you'll be surprised to know it's not really Microsoft's fault.
Scott -
Thanks.
Many have tried both HDMI and TOSLink(optical) you get the same result regardless of what you use.
2 channel content the XBox sends 5.1 or 7.1 channels with only audio on the left and right and the other silent (but present) -
Bump.
Any progress on those test files Cornucopia?
It appears that Microsoft still have not addressed this with their latest update (NXOE - New XBox One Experience)
Someone directed me to these files
http://www.demo-world.eu/2d-demo-trailers-hd/
I did some testing with those however there really is no demo which tells you which speaker a sound should come from which is why I would love these custom made example ones.
I tested a few 7.1 channel videos.
One thing I did find was that when the XBox One was in "Bitstream Out" mode it worked on these files (using Plex app) on all 7.1 speakers.
However when the XBox One was in "7.1 uncompressed" the videos only played back on 5.1 speakers.
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