From 6fc0b459e7837973a414695731abd225f09bdab0 Mon Sep 17 00:00:00 2001 From: Que Quotion Date: Sun, 27 Jun 2021 15:15:59 +0900 Subject: [PATCH] doc: new a52 input formats, global config Document the new preconfiguration and libavcodec version-dependent input formats. Signed-off-by: Que Quotion Signed-off-by: Jaroslav Kysela --- doc/a52.txt | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/doc/a52.txt b/doc/a52.txt index ce7ee33..c113d57 100644 --- a/doc/a52.txt +++ b/doc/a52.txt @@ -1,11 +1,17 @@ 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. +This plugin converts S16(P), S32P, or FLTP formats to an A52 compressed +stream and sends it to an S/PDIF output. It requires libavcodec for +encoding the audio stream. -A PCM using this plugin can be defined like below: +The input format is determined by the version of libavcodec it is +compiled against and which ac3 codec libavcodec is configured to use. + +A global configuration, /usr/share/alsa/alsa.conf.d/60-a52-encoder.conf +defines a52 PCMs for devices with the IEC958 non-audio status bit set. + +A PCM using this plugin can be manually defined like below: pcm.myout { type a52 @@ -61,5 +67,6 @@ For using slavepcm option, } -The plugin reads always S16 format (i.e. native-endian) as input, so -you'd need plug layer appropriately to covert it. +The plugin only reads the format determined by libavcodec (native- +endian S16(P), S32P or FLTP) as input, so you'll need a plug layer to +appropriately convert it. -- 2.47.1