[PATCH 1/3 v2] speaker-test: Fix chmapped channel selection without specified chmap

[Anssi Hannula <anssi.hannula@iki.fi>]

The channel selection currently does not work properly when there is a
driver-provided non-ALSA-traditional channel map but no manual channel
map was explicitely requested with "-m".

For example, the CEA/HDMI 8ch map is FL,FR,RLC,RRC,FC,LFE,RL,RR. Note
that it is otherwise the same as the traditional ALSA channel map,
except that the traditional rear speakers are considered
rear-center speakers and the traditional side speakers are considered
rear speakers.

Speaker-test tries to play back channels in this following order:
  0, /* Front Left  */
  4, /* Center      */
  1, /* Front Right */
  7, /* Side Right  */
  3, /* Rear Right  */
  2, /* Rear Left   */
  6, /* Side Left   */
  5, /* LFE         */

When it is the time to play back Side Left/Right, speaker-test tries to
look for SL/SR in the chmap, but doesn't find it, so it just plays back
channels 6/7 (which indeed are the side speakers, or RL/RR in this
channel map - so the correct channels are selected).

When it becomes the time to playback Rear Left/Right, speaker-test again
tries to find RL/RR in the chmap, and this time it does find them in the
chmap positions 6/7.

So the channels 6/7 are tested twice and 2/3 are never tested.

To fix this, define a generic playback order channel_order[] to be used
when the channel map is present (but not user-defined) and generate a
(speaker/playback number => channel number) mapping with the channels
ordered in the following order:
1. regular channels found in channel_order[] in the defined order,
2. channels not found in channel_order[] ordered by channel number.
3. UNKNOWN channels ordered by channel number.
4. NA channels ordered by channel number.
For channels outside the channel map just use their channel numbers (so
they will be last after all of the above).

For example, if the playback device has a fictional default channel map
of FR,FL,UNKNOWN1,FOO,BAR,RR,RL,UNKNOWN2, the playback order will be
FL,FR,RR,RL,FOO,BAR,UNKNOWN1,UNKNOWN2(,any_extra_channels).

When the channel mapping is specified manually, the specified order is
used for playback as before.

Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
---
 speaker-test/speaker-test.c | 113 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 91 insertions(+), 22 deletions(-)

diff --git a/speaker-test/speaker-test.c b/speaker-test/speaker-test.c
index 45e92e5..261f399 100644
--- a/speaker-test/speaker-test.c
+++ b/speaker-test/speaker-test.c
@@ -88,6 +88,8 @@ enum {
 #define BE_INT(v)		(v)
 #endif
 
+#define ARRAY_SIZE(x) (int)(sizeof(x)/sizeof(x[0]))
+
 static char              *device      = "default";       /* playback device */
 static snd_pcm_format_t   format      = SND_PCM_FORMAT_S16; /* sample format */
 static unsigned int       rate        = 48000;	            /* stream rate */
@@ -110,6 +112,7 @@ static snd_pcm_t *pcm_handle = NULL;
 #ifdef CONFIG_SUPPORT_CHMAP
 static snd_pcm_chmap_t *channel_map;
 static int channel_map_set;
+static unsigned int *ordered_channels;
 #endif
 
 static const char *const channel_name[MAX_CHANNELS] = {
@@ -156,36 +159,94 @@ static const int	channels8[] = {
   5, /* LFE         */
 };
 
-static int get_mapped_channel(int chn)
-{
 #ifdef CONFIG_SUPPORT_CHMAP
-  static const int maps[MAX_CHANNELS] = {
-    SND_CHMAP_FL,
-    SND_CHMAP_FR,
-    SND_CHMAP_RL,
-    SND_CHMAP_RR,
-    SND_CHMAP_FC,
-    SND_CHMAP_LFE,
-    SND_CHMAP_SL,
-    SND_CHMAP_SR,
-  };
+/* circular clockwise and bottom-to-top order */
+static const int channel_order[] = {
+  [SND_CHMAP_FLW]  =  10,
+  [SND_CHMAP_FL]   =  20,
+  [SND_CHMAP_TFL]  =  30,
+  [SND_CHMAP_FLC]  =  40,
+  [SND_CHMAP_TFLC] =  50,
+  [SND_CHMAP_FC]   =  60,
+  [SND_CHMAP_TFC]  =  70,
+  [SND_CHMAP_FRC]  =  80,
+  [SND_CHMAP_TFRC] =  90,
+  [SND_CHMAP_FR]   = 100,
+  [SND_CHMAP_TFR]  = 110,
+  [SND_CHMAP_FRW]  = 120,
+  [SND_CHMAP_SR]   = 130,
+  [SND_CHMAP_TSR]  = 140,
+  [SND_CHMAP_RR]   = 150,
+  [SND_CHMAP_TRR]  = 160,
+  [SND_CHMAP_RRC]  = 170,
+  [SND_CHMAP_RC]   = 180,
+  [SND_CHMAP_TRC]  = 190,
+  [SND_CHMAP_RLC]  = 200,
+  [SND_CHMAP_RL]   = 210,
+  [SND_CHMAP_TRL]  = 220,
+  [SND_CHMAP_SL]   = 230,
+  [SND_CHMAP_TSL]  = 240,
+  [SND_CHMAP_BC]   = 250,
+  [SND_CHMAP_TC]   = 260,
+  [SND_CHMAP_LLFE] = 270,
+  [SND_CHMAP_LFE]  = 280,
+  [SND_CHMAP_RLFE] = 290,
+  /* not in table  = 10000 */
+  [SND_CHMAP_UNKNOWN] = 20000,
+  [SND_CHMAP_NA]      = 30000,
+};
 
-  if (channel_map && maps[chn]) {
-    int i;
-    for (i = 0; i < channel_map->channels; i++) {
-      if (channel_map->pos[i] == maps[chn])
-	return i;
-    }
+static int chpos_cmp(const void *chnum1p, const void *chnum2p)
+{
+  int chnum1 = *(int *)chnum1p;
+  int chnum2 = *(int *)chnum2p;
+  int chpos1 = channel_map->pos[chnum1];
+  int chpos2 = channel_map->pos[chnum2];
+  int weight1 = 10000;
+  int weight2 = 10000;
+
+  if (chpos1 < ARRAY_SIZE(channel_order) && channel_order[chpos1])
+    weight1 = channel_order[chpos1];
+  if (chpos2 < ARRAY_SIZE(channel_order) && channel_order[chpos2])
+    weight2 = channel_order[chpos2];
+
+  if (weight1 == weight2) {
+    /* order by channel number if both have the same position (e.g. UNKNOWN)
+     * or if neither is in channel_order[] */
+    return chnum1 - chnum2;
   }
-#endif
-  return chn;
+
+  /* order according to channel_order[] */
+  return weight1 - weight2;
+}
+
+static int *order_channels(void)
+{
+  /* create a (playback order => channel number) table with channels ordered
+   * according to channel_order[] values */
+  int i;
+  int *ordered_chs;
+
+  ordered_chs = calloc(channel_map->channels, sizeof(*ordered_chs));
+  if (!ordered_chs)
+    return NULL;
+
+  for (i = 0; i < channel_map->channels; i++)
+    ordered_chs[i] = i;
+
+  qsort(ordered_chs, channel_map->channels, sizeof(*ordered_chs), chpos_cmp);
+
+  return ordered_chs;
 }
+#endif
 
 static int get_speaker_channel(int chn)
 {
 #ifdef CONFIG_SUPPORT_CHMAP
-  if (channel_map_set)
+  if (channel_map_set || (ordered_channels && chn >= channel_map->channels))
     return chn;
+  if (ordered_channels)
+    return ordered_channels[chn];
 #endif
 
   switch (channels) {
@@ -200,7 +261,7 @@ static int get_speaker_channel(int chn)
     break;
   }
 
-  return get_mapped_channel(chn);
+  return chn;
 }
 
 static const char *get_channel_name(int chn)
@@ -613,6 +674,11 @@ static int config_chmap(snd_pcm_t *handle, const char *mapstr)
   }
 
   channel_map = snd_pcm_get_chmap(handle);
+
+  /* create a channel order table for default layouts */
+  if (channel_map)
+    ordered_channels = order_channels();
+
   return 0;
 }
 #endif
@@ -1232,6 +1298,9 @@ int main(int argc, char *argv[]) {
 
 
   free(frames);
+#ifdef CONFIG_SUPPORT_CHMAP
+  free(ordered_channels);
+#endif
 
   return prg_exit(EXIT_SUCCESS);
 }
-- 
1.8.1.5