ffplay: try more channel count combinations for SDL_OpenAudio

This should fix ticket 1384.
Signed-off-by: Marton Balint <cus@passwd.hu>

ffplay.c

@@ -2246,6 +2246,7 @@ static int audio_open(void *opaque, int64_t wanted_channel_layout, int wanted_nb
 {
     SDL_AudioSpec wanted_spec, spec;
     const char *env;
+    const int next_nb_channels[] = {0, 0, 1, 6, 2, 6, 4, 6};
 
     env = SDL_getenv("SDL_AUDIO_CHANNELS");
     if (env) {
@@ -2255,12 +2256,6 @@ static int audio_open(void *opaque, int64_t wanted_channel_layout, int wanted_nb
     if (!wanted_channel_layout || wanted_nb_channels != av_get_channel_layout_nb_channels(wanted_channel_layout)) {
         wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
         wanted_channel_layout &= ~AV_CH_LAYOUT_STEREO_DOWNMIX;
-        wanted_nb_channels = av_get_channel_layout_nb_channels(wanted_channel_layout);
-        /* SDL only supports 1, 2, 4 or 6 channels at the moment, so we have to make sure not to request anything else. */
-        while (wanted_nb_channels > 0 && (wanted_nb_channels == 3 || wanted_nb_channels == 5 || wanted_nb_channels > (SDL_VERSION_ATLEAST(1, 2, 8) ? 6 : 2))) {
-            wanted_nb_channels--;
-            wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
-        }
     }
     wanted_spec.channels = av_get_channel_layout_nb_channels(wanted_channel_layout);
     wanted_spec.freq = wanted_sample_rate;
@@ -2273,10 +2268,15 @@ static int audio_open(void *opaque, int64_t wanted_channel_layout, int wanted_nb
     wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
     wanted_spec.callback = sdl_audio_callback;
     wanted_spec.userdata = opaque;
-    if (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
-        fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
+    while (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
+        fprintf(stderr, "SDL_OpenAudio (%d channels): %s\n", wanted_spec.channels, SDL_GetError());
+        wanted_spec.channels = next_nb_channels[FFMIN(7, wanted_spec.channels)];
+        if (!wanted_spec.channels) {
+            fprintf(stderr, "No more channel combinations to try, audio open failed\n");
             return -1;
         }
+        wanted_channel_layout = av_get_default_channel_layout(wanted_spec.channels);
+    }
     if (spec.format != AUDIO_S16SYS) {
         fprintf(stderr, "SDL advised audio format %d is not supported!\n", spec.format);
         return -1;