[MPlayer-dev-eng] [PATCH] libao2/ao_alsa9.c: allow playing 8-bit audio

[R.L. Horn]

The enclosed patch should fix problems associated with playing 8-bit wide
audio samples (or anything other than 16-bit samples, for that matter)
using the alsa9 ao driver.

The problem arises because of the following declaration in play_normal():

  signed short *output_samples=data;

Later on:

  output_samples += ao_data.channels * res;

Unfortunately, samples aren't always shorts, so this can cause some
ugly weirdness.

The patch changes output_samples to a char * and replaces the increment
with:

  output_samples += res * bytes_per_sample;

This seems to fix things.
-------------- next part --------------
diff -aur main-old/libao2/ao_alsa9.c main/libao2/ao_alsa9.c
--- main-old/libao2/ao_alsa9.c	2002-11-02 04:59:27.000000000 -0600
+++ main/libao2/ao_alsa9.c	2002-12-03 02:20:46.000000000 -0600
@@ -853,10 +853,16 @@
 
   //bytes_per_sample is always 4 for 2 chn S16_LE
   int num_frames = len / bytes_per_sample;
+
+/*
+  Output data aren't always 16-bits wide.  Use char instead of short.
   signed short *output_samples=data;
+*/
+  char *output_samples = (char *)data;
   snd_pcm_sframes_t res = 0;
 
-  //printf("alsa-play: frames=%i, len=%i",num_frames,len);
+  /* XXX */
+  //fprintf(stderr,"alsa-play: frames=%i, len=%i\n",num_frames,len);
 
   if (!alsa_handler) {
     printf("alsa-play: device configuration error");
@@ -891,7 +897,10 @@
       }
 
       if (res > 0) {
-	output_samples += ao_data.channels * res;
+
+	/* output_samples += ao_data.channels * res; */
+	output_samples += res * bytes_per_sample;
+
 	num_frames -= res;
       }