Dolby Audio Processing
Annabella Wasik
I'd been having weird audio issues since getting my Nvidia Shield Pro 2019. When starting a movie or tv show file, the audio would take a second to kick in after the video has already started. It'd be in sync, but odd nonetheless. I also noticed that LIVE TV would fall out of sync over time. I'd have to stop and restart the show.
However, the real annoying problem I was having was while watching football games that I edit and encode from recordings - I like to re-watch NFL games. All the files would start out as direct play, but when I'd start to use FF to skip between plays or rewind to watch a play again, playback eventually would move over to direct stream then full on transcoding and throw a DirectPlay error. Logs would show that it was all audio related.
I never had issues with direct play of my football games with my previous HTPC, so I thought maybe it had something to do with Emby Android TV, but then I realized that I also use Emby Android TV on my FireTV and do not have these issues on it.
So I was back to wondering what is with this Nvidia Shield that could be causing these problems? I searched the forums here and didn't find anything related to my issue and after looking in the Nvidia Shield's settings and finding what I think has solved everything, I looked again on the forums to see if anyone else pointed it out. No one has or I can't find it ... so here's what solved it for me:
Under Nvidia Shield Settings > Device Preferences > Display & Sound > Advanced sound setttings > Dolby audio processing was toggled ON. I toggled it OFF and have not had any of the above issues since.
I have the latest Nvidia Shield update 8.2.0(32.6.435.1) which may have somehow toggled that ON by default or it's always been on since I've had it. I surmise that this Dolby audio processing was forcing the Shield to always process regardless if it's connected to a receiver that can do the work, therefore causing delays and sync issues. Just a single click and all is well.
"The main purpose of this feature is to convert Dolby Digital Plus (EAC3) to Dolby Digital (AC3) on streaming apps for people who use older receivers that don't support EAC3. It does not do any simulated surround processing, but there is an upmix to 5.1 feature in the audio settings that is seperate from this that does upmixing to surround."
"The main purpose of this feature is to convert Dolby Digital Plus (EAC3) to Dolby Digital (AC3) on streaming apps for people who use older receivers that don't support EAC3. It does not do any simulated surround processing, but there is an upmix to 5.1 feature in the audio settings that is seperate from this that does upmixing to surround."
The football files' audio that these issues really became prevalent on are all Dolby Digital (AC3) therefore not needing any conversion. My equipment is all fairly new and up to date in regards to handling everything thrown at it, so yeah it was throwing me for a loop as to why I was having these problems. I got a Shield after all the reviews and recommendations from friends, so was very frustrated to say the least when these issues started manifesting themselves.
Windows allows OEMs and third-party audio hardware manufacturers to include custom digital signal processing effects as part of their audio driver's value-added features. These effects are packaged as user-mode system effect Audio Processing Objects (APOs).
Audio processing objects (APOs), provide software based digital signal processing for Windows audio streams. An APO is a COM host object that contains an algorithm that is written to provide a specific Digital Signal Processing (DSP) effect. This capability is known informally as an "audio effect." Examples of APOs include graphic equalizers, reverb, tremolo, Acoustic Echo Cancellation (AEC) and Automatic Gain Control (AGC). APOs are COM-based, real-time, in-process objects.
Note The descriptions and terminology in this documentation refers mostly to output devices, such as speakers. However, the technology is symmetric and works essentially in reverse for input devices.
A hardware digital signal processor (DSP) is a specialized microprocessor (or a SIP block), with its architecture optimized for the operational needs of digital signal processing. There can be significant advantages to implement audio processing in purpose built hardware vs. using a software APO. One advantage is that the CPU use and associated power consumption may be lower with a hardware implemented DSP.
Software based effects are inserted in the software device pipe on stream initialization. These solutions do all their effects processing on the main CPU and do not rely on external hardware. This type of solution is best for traditional Windows audio solutions such as HDAudio, USB and Bluetooth devices when the driver and hardware only support RAW processing. For more information about RAW processing, see Audio Signal Processing Modes.
Any effects applied in hardware DSP need to be advertised via a proxy APO. Microsoft provides a default proxy APO (MsApoFxProxy.dll). To use the Microsoft provided APO, this property set and property must be supported.
To allow the user to configure settings associated with your custom APO the recommended approach is to create a Hardware Support App. For more information, see Hardware Support App (HSA): Steps for Driver Developers.
You can use the "Audio Effects Discovery Sample" to explore the available audio effects. This sample demonstrates how to query audio effects on render and capture audio devices and how to monitor changes with the audio effects. It is included as part of the SDK samples and can be downloaded using this link:
Applications have the ability to call APIs to determine which audio effects are currently active on the system. For more information on the audio effects awareness APIs, see AudioRenderEffectsManager class.
A stream effect APO has an instance of the effect for every stream. Stream effects are before the mix (render) or after the tee (capture) for a given mode and can be used for changing channel count before the mixer. Stream effects are not used for raw streams.
Endpoint Effect (EFX) are applied to all streams that use the same endpoint. An endpoint effect is always applied, even to raw streams. That is, it is after the mix (render) or before the tee (capture) of all modes. The endpoint effects should be used with care and when in doubt an effect should be place in the Mode area. Some effects that should be placed in the endpoint area are speaker protection and speaker compensation.
This diagram illustrates how multiple applications can access multiple combinations of stream, mode and endpoint APO effects. All of the APOs are COM based and run in user mode. In this scenario, none of the effects are running in hardware or in kernel mode.
I don't seea bigger difference as 8004 has worked finde for me already. This equalizer tool is a bit confusing for me (I must spend some time do understand the settings which are really available (some seems to be nonsens and don't work).
My advice is, not to use the oudated audio drivers from Acer Site which are really old and buggy. Acer should feel ashamed a bit because they let us sitting here without a propper driver. Just because they don't care or they want to save money for the driver?
Maybe there are some other changes? Realtek 79.. is installed automatically if you do not disabel this function. I didn't have too much time for testing, but with this old driver, problems with Dolby where still there.
MEN PROBLEM FIXED installing the APO EQUALIZER omg THANKS Robitzik just install, select the audio and mic device for the program to take control and restart, open the dolby to see if its activated or not leave opened fot reference... and click cortana mic or any program that use the mic device, and see if still deactivating if not problem fixed like in my case. if still desctivating you are DOOMED!! haha
Hello Everyone! I still have the problem with Dolby on my Predator G9-591. I tried the method with the Equalizer APO 1.1.2, did everything as told, but still Dolby turns off when I'm using Skype or Cortana.
There are still problems with Dolby after disabling all enhancements for both speakers and microphone. Unckecking "Allow applications to take exclusive control of this device" for both of them doesn't help as well. Thank you so much for your help, I think this method just doesn't work for my series.
Hello, I have the update of windows 10 creators (I know because I have the options of game bar as comments and why I install manually) and also I have the equalizer APO and still working perfectly, I have the model Acer Predator G9-973 I do not know if it affects but in my case it works perfectly.
I even had to reinstall the audio drivers and the dolby by mistake, and when I finished I realized that the detail with the microphone persists, but installing the apo equalizer solves the problem again.
The AAP-8644 is a 3G/HD/SD-SDI Advanced Audio Processor offering extensive software-defined DSP audio processing toolbox including Dolby encode/decode, automatic loudness levelling with full embedding and de-embedding. The card also offers an advanced Audio/Video QC option with hardware relay bypass, offering a flexible ACO solution for your critical signal path.
Dolby Audio enables the means to deliver high quality audio experiences to consumers. Dolby has created audio codecs and systems for the delivery of mono, stereo, 5.1, 7.1 and Immersive Audio to consumers for playback in mobile devices, game consoles, laptops and home theater.
Dolby audio codecs provide substantial bitrate reductions, which allows for the delivery of audio by broadcast, streaming and fixed media at a fraction of the bandwidth and file size of uncompressed audio. Dolby codecs as a group are lossy/perceptual codecs, meaning that the codecs use patented psychoacoustic algorithms and processing to achieve bitrate reduction by removing redundant audio content that is imperceptible by the human ear. Dolby audio codecs provide near uncompressed audio quality at low datarates.
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