On Mon, August 30, 2010 5:00 am, Kim Therkelsen wrote: > > Hi, > > I want to make is a DSP module that improves the sound quality > of the sound coming from the laptop builtin speakers by applying DSP > (FIR/IIR filters). > I want to route all audio played back (from for > instance an offline WAV or MP3 file, from a movie, or streamed from the > internet) to > pass through the > DSP plugin whenever headphones are NOT connected. When headphones are > connected no processing should be applied. > I > want to place the DSP module as close to the hardware as possible to > make sure all audio is really routed through the DSP plugin so I always > can enjoy > the DSP improvements made to the sound. > > Where should I place this module/DSP code? > - As a plugin to PulseAudio? > > - As a plugin to ALSA? > - As its own virtual sound card? > > - In the audio driver for my built-in sound card? > - As a kernel module? > > > I have tried loading the LADSPA-module using the module-ladspa-sink in > PulseAudio but I am not sure this is the best solution.
It is the recommended solution if you are using PA for your sound server. > I need to remove some limitations in module-ladspa-sink to get it working > properly ( multichannel audio, only DSP processing for internal speakers). > > > > My requirements: > > 1) Must be able to detect if headphones are connected > IIUC, PA gets this info from ALSA > 2) Must be able to process stereo and multichannel (5.1/7.1) formats. I > need the multichannel formats to perform binaural downmixing to > stereo. I'm not sure how the dolby multichannel support is in ALSA. It may depend on the internal capabilities of the device. > So it is important that I can receive multichannel audio and mix it down > to stereo and output it to a stereo soundcard. > This may better handled in app. -- Patrick Shirkey Boost Hardware Ltd. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
