2 files changed, 36 insertions, 6 deletions

diff --git a/apps/talk.c b/apps/talk.c
index a49de09e84..ab9ca8c495 100644
--- a/apps/talk.c
+++ b/apps/talk.c
@@ -636,11 +636,10 @@ static bool load_voicefile_data(int fd)
     return true;
 }
 
-/* most, if not all, clips should be well below 32k (largest in english.lang is
- * 4.5K). Currently there is a problem with voice decoding such that clips
- * cannot be decoded in chunks. Once that is resolved this buffer could be
- * smaller and clips be decoded in multiple chunks */
-static unsigned char commit_buffer[32<<10];
+/* Use a static buffer to avoid difficulties with buflib during DMA
+ * (hwcodec)/buffer passing to the voice_thread (swcodec). Clips
+ * can be played in chunks so the size is not that important */
+static unsigned char commit_buffer[1<<10];
 
 static void* commit_transfer(struct queue_entry *qe, size_t *size)
 {
@@ -658,7 +657,6 @@ static void* commit_transfer(struct queue_entry *qe, size_t *size)
     memcpy(bufpos, buf, sent);
     *size = sent;
 
-
     return commit_buffer;
 }
 
@@ -674,6 +672,13 @@ static inline bool is_silence(struct queue_entry *qe)
 static void mp3_callback(const void** start, size_t* size)
 {
     struct queue_entry *qe = &queue[queue_read];
+#if CONFIG_CODEC == SWCODEC
+    /* voice_thread.c hints us how many of the buffer we provided it actually
+     * consumed. Because buffers have to be frame-aligned for speex
+     * it might be less than what we presented */
+    if (*size)
+        sent = *size;
+#endif
     qe->remaining -= sent; /* we completed this */
 
     if (qe->remaining > 0) /* current clip not finished? */
diff --git a/apps/voice_thread.c b/apps/voice_thread.c
index 72ecb3741e..dcb7eef224 100644
--- a/apps/voice_thread.c
+++ b/apps/voice_thread.c
@@ -63,9 +63,17 @@
    latency */
 #define PRIORITY_VOICE (PRIORITY_PLAYBACK-4)
 
+/* A speex frame generally consists of 20ms of audio
+ * (http://www.speex.org/docs/manual/speex-manual/node10.html)
+ * for wideband mode this results in 320 samples of decoded PCM.
+ */
 #define VOICE_FRAME_COUNT   320 /* Samples / frame */
 #define VOICE_SAMPLE_RATE 16000 /* Sample rate in HZ */
 #define VOICE_SAMPLE_DEPTH   16 /* Sample depth in bits */
+/* The max. wideband bitrate is 42.4 kbps
+ * (http://www.speex.org/docs/manual/speex-manual/node11.html). For 20ms
+ * this gives a maximum of 106 bytes for an encoded speex frame */
+#define VOICE_MAX_ENCODED_FRAME_SIZE 106
 
 /* Voice thread variables */
 static unsigned int voice_thread_id = 0;
@@ -449,6 +457,23 @@ static enum voice_state voice_decode(struct voice_thread_data *td)
     }
     else
     {
+        if (td->vi.size > VOICE_MAX_ENCODED_FRAME_SIZE
+            && td->bits.charPtr > (td->vi.size - VOICE_MAX_ENCODED_FRAME_SIZE)
+            && td->vi.get_more != NULL)
+        {
+            /* request more data _before_ running out of data (requesting
+             * more after the fact prevents speex from successful decoding)
+             * place a hint telling the callback how much of the
+             * previous buffer we have consumed such that it can rewind
+             * as necessary */
+            int bitPtr = td->bits.bitPtr;
+            td->vi.size = td->bits.charPtr;
+            td->vi.get_more(&td->vi.start, &td->vi.size);
+            speex_bits_set_bit_buffer(&td->bits, (void *)td->vi.start,
+                                      td->vi.size);
+            td->bits.bitPtr = bitPtr;
+        }
+
         yield();
 
         /* Output the decoded frame */