On Sep 30, 2019, at 11:50 AM, Rafael Machado <rafaelrodrigues.machado@...> wrote:
As you have mentioned:
" I might find some time to try to get the EmulatorPkg mocking working."
Answer: This would be amazing! Thanks for trying to help!
I made a little progress this weekend watching American Football on TV, and I had some time on an airplane today to add some comments.
I wrote a simple C command line program that does almost all the primitive audio functions we need to add Audio/Text-To-Speech to the EmulatorPkg. Since ANSI C does not support audio I had to system() out to macOS command line tools to get some of the tasks complete. The only feature I'm missing is playing the PCM buffer asynchronously, and I may be able to add that next weekend. I guessed at the Linux commands, it would be good if someone could debug the program on a Linux system, and also make sure I picked the right command line tools to use. I think for Windows there is going to be more coding involved, but I think there is at least a C API to play audio, but I only saw a C++ API for speech to text. But the good news is folks can use the simple C program to get the primitives working on Linux and Windows systems and it should be easy to port that work to the future EmulatorPkg work.
What I've got working on macOS is:
3) Text to PCD buffer (Wave file format)
a) Supports word per minute rate
b) Supports localizing the voice based on RFC 4646 language code used by EFI (the program speaks in en, zh, and fr as a test)
4) PCD buffer to audio
This is how I was building on my Mac: clang -g -Wall -Werror audio.c
Short term anyone that has some free time if they could look at testing/debugging audio.c on Linux and send feedback, also maybe some one could start playing around with getting audio.c ported to Windows?
After I figure out getting async audio output working in audio.c I think the next steps are working on the protocol/variable definitions. With the protocol/variable definitions we should be able to add the capability to the EmulatorPkg. At that point it should be possible for anyone to help work on the accessibility UI. Obviously to get this working on a real platform we will need a pure EFI Text to Speech driver (We could debug that in the EmulatorPkg). We would also need Intel HDA Audio drivers, and Audio drivers for OVFM, and other Audio hardware that is on peoples platforms.
The plan is to try to get some students to help on this also at the next "google summer of code".
Not sure how it works, but since the idea is good, and it is a real need, I believe we have chances to have some more hands working on it.
Thanks and Regards
Rafael R. Machado
Em qui, 26 de set de 2019 às 20:44, Andrew Fish <afish@... <mailto:afish@...>> escreveu:
On Sep 26, 2019, at 5:15 AM, Rafael Machado <rafaelrodrigues.machado@... <mailto:rafaelrodrigues.machado@...>> wrote:
About Ethin's question:
As for the boot manager, yes, that would be covered by the speech synthesizer protocol. Perhaps we could extend this to the setup utility too (as well as all other things displayed on the screen)?Answer: This is the target from my point of view. Since we have the advantages of drivers at UEFI, there is no reason for not having accessibility at pre-OS anymore. We could also think in future to add other kinds of accessibility, like the magnifying glass (that would be some multi-layer version of the GOP driver), that would help low-vision people. Just one thing for everyone to think about. The "Convention on the Rights of Persons with Disabilities" say that a person has the right to access information. So if someone buys a notebook, all information accessible to "common" people must be available to all kinds of people, in a way they can choose to use this information or not.
" (e) Recognizing that disability is an evolving concept and that disability results from the interaction between persons with impairments and attitudinal and environmental barriers that hinders their full and effective participation in society on an equal basis with others, ..."
Details can be found at the United Nations web site https://www.un.org/disabilities/documents/convention/convention_accessible_pdf.pdf
About Andrew's comments and questions:
What member functions to you think that EFI_AUDIO_OUTPUT_PROTOCOL should contain?Answer: From my perspective, this protocol would need at least the following functions (names may change after more discussion.)
This function is intended to copy some data to the dma buffers that were allocated previously by the AudioController driver. The initial idea I had was to add, in the case of my MSc, a HdaDriver.efi that is responsible to do all the HDA controller initialization (allocating dma buffers, configuring the PCIe bus if needed). Not sure if this initialization should we added to the EFI_AUDIO_OUTPUT_PROTOCOL, because this could create problems when using other controllers or concepts, like I believe ARM platforms do.My understanding is that the platforms should have a driver to initialize the audio controller/codec, so the EFI_AUDIO_OUTPUT_PROTOCOL is just worried with loading and playing information.
This function is responsible to play the stream. This is done by setting one specific bit at the controllers configuration space (pointed by the bar pcie configuration register at the pcie config space.) At this project I don't think we need to be worried with implementing an sound server to enable multiple streams at a time. To the actions done by this function are much simpler. Just play a stream.
This function is responsible to stop the stream play. The opposite of the previous one. Maybe we could use a single function that receives some parameter to start or stop the play.
This function is responsible to set the volume to be used at all nodes at the codec (so it depends on a EFI_AUDIO_CODEC_PROTOCOL that knows the commands a given codec needs to receive to process streams.)
This function is responsible to set the speed a given stream should be played on. Just to clarify, visual impaired people have an amazing capacity of understanding sound streams in incredibly fast speeds. So the possibility of setting the stream processing speed is what makes them be as productive as a person with usual vision capacities.
This function is responsible to clean the buffers and letting them prepared to receive other audio streams.
Still about Andrews comments.
This gave me the idea of adding a EFI_AUDIO_OUTPUT_PROTOCOL and EFI_TEXT_TO_SPEECH_PROTOCOL driver to the EmulatorPkg that thunk down to the App to do the work. With this we could prototype the UI part of accessibility.Answer: This would be great, because we would split the development. One focusing on the HII and navigation (done normally using the tab key, so each element at the screen would need an tab sequence number and a accessibility tag with what the speech software should say), and another focusing on the drivers/synthesizer/audio files depending on our future decisions.
So my understanding is that the list of things is increasing. It is actually something like this (not ordered by priority):
- EFI_AUDIO_OUTPUT_PROTOCOL: Protocol used to process the streams
- EFI_AUDIO_CODEC_PROTOCOL: Protocol used to communicate with the codec
- Audio configuration driver (HdaAudio.efi for example). Should this create some other protocol, like EFI_AUDIO_CONTROLLER_PROTOCOL that is responsible to configure the controller?
Generally how it works for a PCI device is it gets its Start() function called to bind to the device. So the EFI_AUDIO_OUTPUT_PROTOCOL and EFI_AUDIO_CODEC_PROTOCOL protocols would likely get installed on the PCI IO handle of the HDA PCI hardware. Some basic init will happen during the Start() and the driver could defer some config until one of the member functions is called the 1st time.
So for example on a normal boot the Audio driver may not even get started. So there may have to be an nvram variable to start the driver. We might also need an NVRAM variable for the voice to text driver if it is stored on disk.
- EFI_TEXT_TO_SPEECH_PROTOCOL: Protocol responsible to convert text to speech (using the EFI_AUDIO_OUTPUT_PROTOCOL )I think so and if we can mock an implementation in the EmulatorPkg that would let the HII UI work happen independently of the text to speech, and Audio driver work.
- HII changes to add tab navigation capabilities and accessibility tags at each component on the screen
Are we aligned with the understanding?
I'm on some air plaines in the next weeks (I'm at the airport right now), and my wife is heading to a conference after I get back from my trips. Given my dogs are not very talkative I might find some time to try to get the EmulatorPkg mocking working.
I believe soon we will be prepared to talk about this on a design meeting.
Thanks and Regards
Rafael R. Machado
Em qua, 25 de set de 2019 às 22:08, Andrew Fish <afish@... <mailto:afish@...>> escreveu:
What member functions to you think that EFI_AUDIO_OUTPUT_PROTOCOL should contain?
I'm thinking if we had an EFI_TEXT_TO_SPEECH_PROTOCOL that driver could produce a PCM/Wave buffer, it could then use EFI_AUDIO_OUTPUT_PROTOCOL to play the sound.
I poked around my Mac at lunch and I can generate text to speech from the command line into a wave file via the `say` command line tool. I can play the wave file from the command line via `afplay`. This gave me the idea of adding a EFI_AUDIO_OUTPUT_PROTOCOL and EFI_TEXT_TO_SPEECH_PROTOCOL driver to the EmulatorPkg that thunk down to the App to do the work. With this we could prototype the UI part of accessibility. We could also debug the EFI EFI_TEXT_TO_SPEECH_PROTOCOL in this environment.
On Sep 21, 2019, at 5:36 AM, Rafael Machado <rafaelrodrigues.machado@... <mailto:rafaelrodrigues.machado@...>> wrote:
Sorry for the delay on the response, to many things happening at the same time.
I will try to answer e-mails to this thread every Saturday or Sunday morning at least.
About Andrew's and Laszlo's comments and questions
During my MSc I had to study a lot the audio and BIOS architectures. The idea was to eliminate the first barrier to the creation of a screen reader for pre-OS environment, that was the lack of some open implementation of audio control and actions at UEFI. To do that I studied the Intel High Definition Audio Spec and a lot of UEFI specs to understand better how to do that.
Please let us know what you find out. I probably don''t have the time to help implement this feature, but I happy to help work on the architecture and design for UEFI accessibility on the edk2 mailing lists, and I >>can also represent what ever we come up with at the UEFI Spec Work Group.
The initial target was to do all this development at OVMF, but as far as I could get, the sound card is not available to OVMF. as Laszlo mentioned at this e-mail there are some projects that may help on this, but at the time I was working on my MSc I didn't find this, so I did everything on a real system (a ASUS notebook).
It took me 2 years of work, because I didn't know a lot of things and working on a MSc degree at the same time having a 40hours/week job, being a father and a husband is not an easy task, but it got to what I was expecting.
The evolution of the project was this:
1 - First tests using some registers named "Immediate Registers", that later I noticed that are not mandatory. This is a simple C Major scale:
2 - Some months later I started to work with the Ring Buffers and DMA memory access. For the ones that have good years, it's possible to listen some music behing the noise.
3 - Later, wen I was almost giving up, I noticed that the problem was that one of my write operations was causing some misunderstanding between the audio controller and the audio codec. The controller was sending packets with 16bit depth, but the codec was processing them as 8bit depth
So the conclusion is that doing this at UEFI us much easier that doing at the OS level.
The reference code, that is just a proof-of-concept, and that has several things to be improved, can be found here:
Currently it is just an UEFI Application, but we can convert this to UEFI drivers after some discussion. Everything is released as BDS so companies can use without IP problems.
Just to give some more information about the need of this kind of solution. There is a lot of blind people that work with hardware support, so formatting disk, configuring RAID and booting dual-boot systems is always a challenge to them. Even set the BIOS clock. How to do that without the system's feedback?
I agree this is the way. Writing a white paper as an official EDK2 papers is one of my targets since the beginning of my MSc almost 5 years ago.
It would be hard to have a UEFI mandate for accessibility, given there is no guideline on how a User Interface (UI) works. If accessibility requires some from of hardware abstraction, like audio, then we could >>likely get that into the UEFI Spec. What might be possible is an EDK2 reference implementation of accessibility. Maybe we could use the reference implementation to write a UEFI white paper on design >>for accessibility? I there is an open source implementation, and an official design guide this would make it much easier for advocacy groups to lobby for this feature.
The solution to this would be the porting of some voice synthesizer, so no audio files would need to be stored. There are some open-source implementations that are not GPL.
I've got some experience with accessibility as the macOS EFI OS Loader has a UI for the Full Disk Encryption password. If you press the power button quickly 3 times at the disk encryption password prompt >>accessibility is enabled and Voice Over gets turned on. You then get localized voice prompts when you move between UI elements. Since this is the OS loader all the resources are stored on the disk. You >>quickly run into a range of challenges since, audio is hard, abstracting audio is hard (what codec does firmware have to support), Audio files are not small and firmware is size constrained, the need to localize >>the audio responses causes even more size issues, the boot options are usually written by an OS installer so how would firmware know what to call them?
This was described at my MSc as future works that can continue what I have started.
I totally agree. Amazing words that I didn't have heard yet. Thanks!
I listed a lot of reasons it is hard but as Kennedy stated in his "We choose to go to the Moon!" speech sometimes we chose to do things "not because they are easy, but because they are hard; because that >>goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept". If we have a design that means we can break the problem up into >>smaller parts, and maybe we can find people that have expertise in that part to build a chunk at a time. If we could implement the prototype in OVMF that would show how it works, but run on everyone's >>machines, so that would be really helpful for demos and design review.
As far as I could understand, and with Leif's help, some possible future steps could be (not at this specific order):
- 1) Convert proof-of-concept HDA driver to UEFI driver model with proper PCI discovery.
- 2) Design a prototype EFI_AUDIO_OUTPUT_PROTOCOL, rework driver to produce this and application to discover and consume it.
- 3) Implement a USB Audio Class driver also producing EFI_AUDIO_OUTPUT_PROTOCOL and ensure test application remains functional.
- 4) Separate controller and codec code by creating an EFI_AUDIO_CODEC_PROTOCOL, implement this in HDA driver, and separate out the codec support into individual drivers.
- 5) Prototype audio output additions to HII. (using pre-recorder audio files)
- 6) Porting of some voice synthesizer to UEFI. (eliminating the need of audio files)
Beyond this, there are other things we should look at adding, like
- Audio input additions to HII.
It's a lot of work, but I accept the challenge.
It may take a long time, but it is possible.
I am still trying to find some time to finish the translation of my thesis to English.
I wrote everything in Portuguese because there was not material about UEFI to the Brazilian audience, and another target I have is to show companies that we have people that can work at this kind of projects in Brazil, bringing this kind of development to south america. (Yes, I have complicated target, but I like the challenge :) )
Thanks and Regards
Rafael R. Machado
Em qui, 19 de set de 2019 às 14:45, Laszlo Ersek <lersek@... <mailto:lersek@...>> escreveu:
On 09/18/19 19:57, Andrew Fish wrote:
Rafael,Somewhat related, in April there was a thread on virtio-dev that
Please let us know what you find out. I probably don''t have the time
to help implement this feature, but I happy to help work on the
architecture and design for UEFI accessibility on the edk2 mailing
lists, and I can also represent what ever we come up with at the UEFI
Spec Work Group.
It would be hard to have a UEFI mandate for accessibility, given
there is no guideline on how a User Interface (UI) works. If
accessibility requires some from of hardware abstraction, like audio,
then we could likely get that into the UEFI Spec. What might be
possible is an EDK2 reference implementation of accessibility. Maybe
we could use the reference implementation to write a UEFI white paper
on design for accessibility? I there is an open source
implementation, and an official design guide this would make it much
easier for advocacy groups to lobby for this feature.
I've got some experience with accessibility as the macOS EFI OS
Loader has a UI for the Full Disk Encryption password. If you press
the power button quickly 3 times at the disk encryption password
prompt accessibility is enabled and Voice Over gets turned on. You
then get localized voice prompts when you move between UI elements.
Since this is the OS loader all the resources are stored on the disk.
You quickly run into a range of challenges since, audio is hard,
abstracting audio is hard (what codec does firmware have to support),
Audio files are not small and firmware is size constrained, the need
to localize the audio responses causes even more size issues, the
boot options are usually written by an OS installer so how would
firmware know what to call them?
I listed a lot of reasons it is hard but as Kennedy stated in his "We
choose to go to the Moon!" speech sometimes we chose to do things
"not because they are easy, but because they are hard; because that
goal will serve to organize and measure the best of our energies and
skills, because that challenge is one that we are willing to accept".
If we have a design that means we can break the problem up into
smaller parts, and maybe we can find people that have expertise in
that part to build a chunk at a time. If we could implement the
prototype in OVMF that would show how it works, but run on everyones
machines, so that would be really helpful for demos and design
suggests there is interest in a virtio-audio device model:
It looks like the ACRN project already implements a (non-standard, as of
now) virtio-audio device already:
(This is all I can mention right now.)