I'm using the intel media sdk under windows 8.1 to encode/decode several streams. The problem I have is under Hardware mode when I try to initiate a second encoder the function returns MFX_ERR_DEVICE_FAILED, but the first encoder is correctly initialized.
Under software mode there is no problem at all. I can generate all encoders.
does anyone know what could be happening?
Are you using different sessions for each HW encoder? If not, that is not correct. You can look at sample_multi_transcode example provided to understand how to initiate multiple media pipelines. https://software.intel.com/en-us/intel-media-server-studio-support/code-samples
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I came across a H.264 video which i would like to play in my c++ application. Could anyone suggest what could be the easiest way of doing it? Or What library can be used for the purpose.
Thanks in advance..
Windows API are DirectShow and Media Foundation (mind availability across Windows verions). You need a codec installed in Windows to be able to play the file, stock codec is only provided with Windows 7 editions. A choice of third party codecs is available.
Another option is to use a different framework such as ffmpeg which includes support for container formats and decoders.
Anyone know of a vorbis decoder library that can be used on Windows Phone 7?
The lack of native code interop make re-using any of the native code implementations difficult (impossible?) but if there are tricks to do that, I'm open to that as well.
There is a managed implementation for mono called csvorbis, it includes a sample which outputs a wav file this didn't need many changes to work with XNA's SoundEffect class. I did a whole track at once, this took a few seconds in the emulator so you may need to stream it using DynamicSoundEffect for better results. The mooncodecs folder has a codec for the desktop version based on csvorbis which may be worth a look aswell.
Ogg Vorbis is not a supported codec on Windows Phone 7 and the platform supports no way of adding support for custom codecs.
The options available are to write your own decoder/converter in managed code or to convert the original source files.
I suspect the second option will be easier.
In Windows XP, you can configure your sound card properties via the preloaded windows software. In the recording properties, if "stereo mix" or "wave out" (or something similar) is selected as the recording device, programs that can record audio ("Sound Recorder" in windows for example) record a decent quality wave file of the audio stream. I usually use Goldwave from download.com to do this as an example of a third-party application that functions the same.
Well, I've had trouble getting this scenario to happen on Windows Vista or later in a direct no-bullsh*t manner as described above. It's more than just Vista+, it's also that some sound cards don't have that option at all.
I was just wondering if there is a way to run a windows-friendly program (VB?) that takes your audio output stream and converts it (in realtime, obviously) to a WAV file with the default sampling rate as other WAV files have.
Ideally, it would cool if it worked on any operating system, so is it possible to write a web service that "listens" to your audio card like that without making the computer think it's getting a virus attack or something?
Possibly related question:
How to save web audio streaming to file ( c++ / java )
I'm only aware of one manufacturer of sound cards that enabled that option (Creative). However Vista and beyond support a "loopback" mode which gives you effectively the same functionality. You need to use the low level WASAPI rendering stack but it should work just fine.
https://github.com/rdp/virtual-audio-output-sniffer provides a directshow input device to capture the sum of wave out for vista+
You could use low level waveOut API injection and capture what it receives.
I have SkypeMXrecorder, a software that does just that - inject into any exe and 'sniffs' what's going out from it and into the sound hardware. But, it seems rather complicated to implement...
I am trying to build what I think is a basic app. Well, two apps one for windows and one for OS X. I would like to capture the audio signal that is playing (ie if the user is playing music out his/her speakers). Then take that signal and stream it out so another computer can "listen". The other computer would be Windows or OS X.
Any ideas on how to get the audio signal?
What's the most efficient way to stream out audio without a 3rd party plugin? If there is an open-source solution out there, I would be interested.
Thanks!
Chris
On Windows XP this isn't trivial at all because there's no way of intercepting the output signal without writing an audio filter driver (which is not somethign for the faint of heart).
On Windows Vista and above, you can capture the output of the audio engine by using the WASAPI APIs (built into Windows so they're free) and initializing an audio client with the AUDCLNT_STREAMFLAGS_LOOPBACK flag. This will give you a capture stream that's hooked to the output of the audio engine.
You can then package up that audio and send it to the other machine and render it with whatever audio rendering API you want.
I don't know how to do the equivilant on OSX though :(.
How would it be possible to capture the audio programmatically? I am implementing an application that streams in real time the desktop on the network. The video part is finished. I need to implement the audio part. I need a way to get PCM data from the sound card to feed to my encoder (implemented using Windows Media Format).
I think the answer is related to the openMixer(), waveInOpen() functions in Win32 API, but I am not sure exactly what should I do.
How to open the necessary channel and how to read PCM data from it?
Thanks in advance.
The new Windows Vista Core Audio APIs have support for this explicitly (called Loopback Recording), so if you can live with a Vista only application this is the way to go.
See the Loopback Recording article on MSDN for instructions on how to do this.
I don't think there is a direct way to do this using the OS - it's a feature that may (or may not) be present on the sound card. Some sound cards have a loopback interface - Creative calls it "What U Hear". You simply select this as the input rather than the microphone, and record from it using the normal waveInOpen() that you already know about.
If the sound card doesn't have this feature then I think you're out of luck other than by doing something crazy like making your own driver. Or you could convince your users to run a cable from the speaker output to the line input :)