Fix qdm2 decoder packet handling to match the api

Originally committed as revision 25767 to svn://svn.ffmpeg.org/ffmpeg/trunk
(cherry picked from commit b26c1a8b7e)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>

libavcodec/qdm2.c

@@ -1906,7 +1906,7 @@ static av_cold int qdm2_decode_close(AVCodecContext *avctx)
 }
 
 
-static void qdm2_decode (QDM2Context *q, const uint8_t *in, int16_t *out)
+static int qdm2_decode (QDM2Context *q, const uint8_t *in, int16_t *out)
 {
     int ch, i;
     const int frame_size = (q->frame_size * q->channels);
@@ -1942,7 +1942,7 @@ static void qdm2_decode (QDM2Context *q, const uint8_t *in, int16_t *out)
 
         if (!q->has_errors && q->sub_packet_list_C[0].packet != NULL) {
             SAMPLES_NEEDED_2("has errors, and C list is not empty")
-            return;
+            return -1;
         }
     }
 
@@ -1963,6 +1963,8 @@ static void qdm2_decode (QDM2Context *q, const uint8_t *in, int16_t *out)
 
         out[i] = value;
     }
+
+    return 0;
 }
 
 
@@ -1971,25 +1973,26 @@ static int qdm2_decode_frame(AVCodecContext *avctx,
             const uint8_t *buf, int buf_size)
 {
     QDM2Context *s = avctx->priv_data;
+    int16_t *out = data;
+    int i;
 
     if(!buf)
         return 0;
     if(buf_size < s->checksum_size)
         return -1;
 
-    *data_size = s->channels * s->frame_size * sizeof(int16_t);
-
     av_log(avctx, AV_LOG_DEBUG, "decode(%d): %p[%d] -> %p[%d]\n",
        buf_size, buf, s->checksum_size, data, *data_size);
 
-    qdm2_decode(s, buf, data);
-
-    // reading only when next superblock found
-    if (s->sub_packet == 0) {
-        return s->checksum_size;
+    for (i = 0; i < 16; i++) {
+        if (qdm2_decode(s, buf, out) < 0)
+            return -1;
+        out += s->channels * s->frame_size;
     }
 
-    return 0;
+    *data_size = (uint8_t*)out - (uint8_t*)data;
+
+    return buf_size;
 }
 
 AVCodec qdm2_decoder =