avcodec/libspeexdec: support zygoaudio

Fixes Ticket1873
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/libspeexdec.c

@@ -33,6 +33,7 @@ typedef struct {
     SpeexStereoState stereo;
     void *dec_state;
     int frame_size;
+    int pktsize;
 } LibSpeexContext;
 
 
@@ -50,14 +51,20 @@ static av_cold int libspeex_decode_init(AVCodecContext *avctx)
             av_log(avctx, AV_LOG_WARNING, "Invalid Speex header\n");
     }
     if (avctx->codec_tag == MKTAG('S', 'P', 'X', 'N')) {
+        int quality;
         if (!avctx->extradata || avctx->extradata && avctx->extradata_size < 47) {
             av_log(avctx, AV_LOG_ERROR, "Missing or invalid extradata.\n");
             return AVERROR_INVALIDDATA;
         }
-        if (avctx->extradata[37] != 10) {
+
+        quality = avctx->extradata[37];
+        if (quality > 10) {
             av_log(avctx, AV_LOG_ERROR, "Unsupported quality mode.\n");
             return AVERROR_PATCHWELCOME;
         }
+
+        s->pktsize = ((int[]){5,10,15,20,20,28,28,38,38,46,62})[quality];
+
         spx_mode           = 0;
     } else if (header) {
         avctx->sample_rate = header->rate;
@@ -143,9 +150,11 @@ static int libspeex_decode_frame(AVCodecContext *avctx, void *data,
             *got_frame_ptr = 0;
             return buf_size;
         }
+        if (s->pktsize && buf_size == 62)
+            buf_size = s->pktsize;
         /* set new buffer */
         speex_bits_read_from(&s->bits, buf, buf_size);
-        consumed = buf_size;
+        consumed = avpkt->size;
     }
 
     /* decode a single frame */