alsa-plugins-1.1.0.tar.gz_alsa

A52 OUTPUT PLUGIN ================= This plugin converts S16 linear format to A52 compressed stream and send to an SPDIF output. It requires libavcodec for encoding the audio stream. A PCM using this plugin can be defined like below: pcm.myout { type a52 } In addition, the following options are available: - The "card" option specifies the card ID or number of the SPDIF. The output PCM becomes "iec958:{CARD=$CARD}" with extra AESx settings. When omitted, the default card is used. - The "slavepcm" option specifies a string of the slave PCM explicitly. This is useful if a device has no proper SPDIF configuration (e.g. usb-audio), or if you want to pass your own PCM definition. This option is exclusive with "card" option. - The "rate" option specifies the input/output sample rate in HZ. The accepted rate is either 44100 or 48000. When omitted, 48000 is used. - The "channels" option specifies the number of _input_ channels. It must be either 2, 4 or 6. The default value is 6. - The "bitrate" option specifies the bit-rate of the compressed stream in kbps. Too small or too big value may not be accepted by the encoder. When omitted, 448 is used. - The "format" option specifies the output format type. It's either S16_LE or S16_BE. As default, S16_LE is used. An example using the secondary card, 44.1kHz, 4 channels, output bitrate 256kbps and output format S16_BE looks like below: pcm.myout { type a52 card 1 rate 44100 channels 4 bitrate 256 format S16_BE } For using slavepcm option, pcm.mypcm { card 1 device 2 } pcm.myout { type a52 slavepcm "mypcm" } The plugin reads always S16 format (i.e. native-endian) as input, so you'd need plug layer appropriately to covert it.