Add request_channels member to AVCodecContext so we now have a proper

way to tell the decoder how many output channels we would like.

Originally committed as revision 10199 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -33,8 +33,8 @@
 #define AV_STRINGIFY(s)         AV_TOSTRING(s)
 #define AV_TOSTRING(s) #s
 
-#define LIBAVCODEC_VERSION_INT  ((51<<16)+(41<<8)+0)
-#define LIBAVCODEC_VERSION      51.41.0
+#define LIBAVCODEC_VERSION_INT  ((51<<16)+(42<<8)+0)
+#define LIBAVCODEC_VERSION      51.42.0
 #define LIBAVCODEC_BUILD        LIBAVCODEC_VERSION_INT
 
 #define LIBAVCODEC_IDENT        "Lavc" AV_STRINGIFY(LIBAVCODEC_VERSION)
@@ -2123,6 +2123,13 @@ typedef struct AVCodecContext {
      * - decoding: unused
      */
     int64_t timecode_frame_start;
+
+    /**
+     * Decoder should decode to this many channels if it can (0 for default)
+     * - encoding: unused
+     * - decoding: Set by user.
+     */
+    int request_channels;
 } AVCodecContext;
 
 /**

libavcodec/dca.c

@@ -1158,6 +1158,7 @@ static int dca_decode_frame(AVCodecContext * avctx,
     avctx->bit_rate = s->bit_rate;
 
     channels = s->prim_channels + !!s->lfe;
+    avctx->channels = avctx->request_channels;
     if(avctx->channels == 0) {
         avctx->channels = channels;
     } else if(channels < avctx->channels) {

libavcodec/utils.c

@@ -753,6 +753,7 @@ static const AVOption options[]={
 {"timecode_frame_start", "GOP timecode frame start number, in non drop frame format", OFFSET(timecode_frame_start), FF_OPT_TYPE_INT, 0, 0, INT_MAX, V|E},
 {"drop_frame_timecode", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_DROP_FRAME_TIMECODE, INT_MIN, INT_MAX, V|E, "flags2"},
 {"non_linear_q", "use non linear quantizer", 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_NON_LINEAR_QUANT, INT_MIN, INT_MAX, V|E, "flags2"},
+{"request_channels", "set desired number of audio channels", OFFSET(request_channels), FF_OPT_TYPE_INT, DEFAULT, 0, INT_MAX, A|D},
 {NULL},
 };