Enable setting of global output samplerate on certain targets.

Replaces the NATIVE_FREQUENCY constant with a configurable frequency.

The user may select 48000Hz if the hardware supports it. The default is
still 44100Hz and the minimum is 44100Hz. The setting is located in the
playback settings, under "Frequency".

"Frequency" was duplicated in english.lang for now to avoid having to
fix every .lang file for the moment and throwing everything out of sync
because of the new play_frequency feature in features.txt. The next
cleanup should combine it with the one included for recording and
generalize the ID label.

If the hardware doesn't support 48000Hz, no setting will be available.

On particular hardware where very high rates are practical and desireable,
the upper bound can be extended by patching.

The PCM mixer can be configured to play at the full hardware frequency
range. The DSP core can configure to the hardware minimum up to the
maximum playback setting (some buffers must be reserved according to
the maximum rate).

If only 44100Hz is supported or possible on a given target for playback,
using the DSP and mixer at other samperates is possible if the hardware
offers them.

Change-Id: I6023cf0c0baa8bc6292b6919b4dd3618a6a25622
Reviewed-on: http://gerrit.rockbox.org/479
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/apps/playback.c b/apps/playback.c
index 24c268f..8b498f2 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -2028,8 +2028,11 @@ static int audio_fill_file_buffer(void)
     /* Must reset the buffer before use if trashed or voice only - voice
        file size shouldn't have changed so we can go straight from
        AUDIOBUF_STATE_VOICED_ONLY to AUDIOBUF_STATE_INITIALIZED */
-    if (buffer_state != AUDIOBUF_STATE_INITIALIZED)
+    if (buffer_state != AUDIOBUF_STATE_INITIALIZED ||
+        !pcmbuf_is_same_size())
+    {
         audio_reset_buffer(AUDIOBUF_STATE_INITIALIZED);
+    }
 
     logf("Starting buffer fill");
 
@@ -2510,6 +2513,11 @@ static void audio_start_playback(size_t offset, unsigned int flags)
 #ifndef PLATFORM_HAS_VOLUME_CHANGE
         sound_set_volume(global_settings.volume);
 #endif
+#ifdef HAVE_PLAY_FREQ
+        settings_apply_play_freq(global_settings.play_frequency, true);
+#endif
+        pcmbuf_update_frequency();
+
         /* Be sure channel is audible */
         pcmbuf_fade(false, true);
 
@@ -3755,6 +3763,7 @@ void INIT_ATTR playback_init(void)
     mutex_init(&id3_mutex);
     track_list_init();
     buffering_init();
+    pcmbuf_update_frequency();
     add_event(PLAYBACK_EVENT_VOICE_PLAYING, false, playback_voice_event);
 #ifdef HAVE_CROSSFADE
     /* Set crossfade setting for next buffer init which should be about... */