1 files changed, 43 insertions, 0 deletions
diff --git a/DOCS/tech/general.txt b/DOCS/tech/general.txt
index ff32fe7825..90bd695220 100644
--- a/DOCS/tech/general.txt
+++ b/DOCS/tech/general.txt
@@ -232,4 +232,47 @@ Now, go on:
     flip_page(): this is called after each frame, this diplays the buffer for
 	 real. This is 'swapbuffers' when double-buffering.
 
+6. libao2: this control audio playing
+
+  As in libvo (see 5.) also here are some drivers, based on the same API:
+
+statis int control(int cmd, int arg);
+  This is for reading/setting driver-specific and other special parameters.
+  Not really used for now.
+
+static int init(int rate,int channels,int format,int flags);
+  The init of driver, opens device, sets sample rate, channels, sample format
+  parameters.
+  Sample format: usually AFMT_S16_LE or AFMT_U8, for more definitions see
+  dec_audio.c and linux/soundcards.h files!
+
+static void uninit();
+  Guess what.
+  Ok I help: closes the device, not (yet) called when exit.
+
+statis void reset();
+  Resets device. To be exact, it's for deleting buffers' contents,
+  so after reset() the previously received stuff won't be output.
+  (called if pause or seek)
+
+static int get_space();
+  Returns how many bytes can be written into the audio buffer without
+  blocking (making caller process wait). If the buffer is (nearly) full,
+  has to return 0!
+  If it never gives 0, MPlayer won't work!
+
+static int play(void* data,int len,int flags);
+  Plays a bit of audio, which is received throught the "data" memory area, with
+  a size of "len". The "flags" isn't used yet. It has to copy the data, because
+  they can be overwritten after the call is made. Doesn't really have to use
+  all the bytes, it has to give back how many have been used (copied to
+  buffer).
+
+static int get_delay();
+  Has to return how many bytes are in the audio buffer. Be exact, if possible,
+  since the whole timing depends on this! In the worst case, return the size
+  of the buffer.
+
+!!! Because the video is synchronized to the audio (card), it's very important
+!!! that the get_space and get_delay are working!