avcodec/h263dec: Use function ptr for decode_picture_header

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/h263dec.c

@@ -121,6 +121,7 @@ av_cold int ff_h263_decode_init(AVCodecContext *avctx)
     case AV_CODEC_ID_H263:
     case AV_CODEC_ID_H263P:
         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
+        h->decode_header = ff_h263_decode_picture_header;
         break;
     case AV_CODEC_ID_MPEG4:
         break;
@@ -144,13 +145,20 @@ av_cold int ff_h263_decode_init(AVCodecContext *avctx)
         s->h263_pred       = 1;
         s->msmpeg4_version = MSMP4_WMV2;
         break;
-    case AV_CODEC_ID_H263I:
     case AV_CODEC_ID_RV10:
     case AV_CODEC_ID_RV20:
         break;
+#if CONFIG_H263I_DECODER
+    case AV_CODEC_ID_H263I:
+        h->decode_header = ff_intel_h263_decode_picture_header;
+        break;
+#endif
+#if CONFIG_FLV_DECODER
     case AV_CODEC_ID_FLV1:
         s->h263_flv = 1;
+        h->decode_header = ff_flv_decode_picture_header;
         break;
+#endif
     default:
         av_unreachable("Switch contains a case for every codec using ff_h263_decode_init()");
     }
@@ -461,22 +469,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict,
     bak_height = h->c.height;
 
     /* let's go :-) */
-    if (CONFIG_WMV2_DECODER && h->c.msmpeg4_version == MSMP4_WMV2) {
-        ret = ff_wmv2_decode_picture_header(h);
-#if CONFIG_MSMPEG4DEC
-    } else if (h->c.msmpeg4_version != MSMP4_UNUSED) {
-        ret = ff_msmpeg4_decode_picture_header(h);
-#endif
-    } else if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4) {
-        ret = ff_mpeg4_decode_picture_header(h);
-    } else if (CONFIG_H263I_DECODER && h->c.codec_id == AV_CODEC_ID_H263I) {
-        ret = ff_intel_h263_decode_picture_header(h);
-    } else if (CONFIG_FLV_DECODER && h->c.h263_flv) {
-        ret = ff_flv_decode_picture_header(h);
-    } else {
-        ret = ff_h263_decode_picture_header(h);
-    }
-
+    ret = h->decode_header(h);
     if (ret < 0 || ret == FRAME_SKIPPED) {
         if (   h->c.width  != bak_width
             || h->c.height != bak_height) {

libavcodec/h263dec.h

@@ -25,11 +25,6 @@
 #include "vlc.h"
 #include "libavutil/mem_internal.h"
 
-/**
- * Return value for header parsers if frame is not coded.
- * */
-#define FRAME_SKIPPED 100
-
 // The defines below define the number of bits that are read at once for
 // reading vlc values. Changing these may improve speed and data cache needs
 // be aware though that decreasing them may need the number of stages that is
@@ -72,6 +67,9 @@ typedef struct H263DecContext {
     int rv10_version; ///< RV10 version: 0 or 3
     int rv10_first_dc_coded[3];
 
+    int (*decode_header)(struct H263DecContext *const h);
+#define FRAME_SKIPPED 100 ///< Frame is not coded
+
     int (*decode_mb)(struct H263DecContext *h);
 #define SLICE_OK         0
 #define SLICE_ERROR     -1

libavcodec/mpeg4videodec.c

@@ -3736,7 +3736,7 @@ end:
         return decode_vop_header(ctx, gb, parse_only);
 }
 
-int ff_mpeg4_decode_picture_header(H263DecContext *const h)
+static int mpeg4_decode_picture_header(H263DecContext *const h)
 {
     Mpeg4DecContext *const ctx = h263_to_mpeg4(h);
 
@@ -4017,6 +4017,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
 
     h->c.h263_pred = 1;
     h->c.low_delay = 0; /* default, might be overridden in the vol header during header parsing */
+    h->decode_header = mpeg4_decode_picture_header;
     h->decode_mb   = mpeg4_decode_mb;
     ctx->time_increment_bits = 4; /* default value for broken headers */
     ctx->quant_precision     = 5;

libavcodec/mpeg4videodec.h

@@ -109,7 +109,6 @@ typedef struct Mpeg4DecContext {
     int dct_precision;
 } Mpeg4DecContext;
 
-int ff_mpeg4_decode_picture_header(H263DecContext *const h);
 int ff_mpeg4_parse_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb,
                                   int header, int parse_only);
 void ff_mpeg4_decode_studio(MpegEncContext *s, uint8_t *dest_y, uint8_t *dest_cb,

libavcodec/msmpeg4dec.c

@@ -360,7 +360,7 @@ static av_cold void msmpeg4_decode_init_static(void)
     ff_msmp4_vc1_vlcs_init_once();
 }
 
-int ff_msmpeg4_decode_picture_header(H263DecContext *const h)
+static int msmpeg4_decode_picture_header(H263DecContext *const h)
 {
     MSMP4DecContext *const ms = mpv_to_msmpeg4(h);
     int code;
@@ -445,7 +445,7 @@ int ff_msmpeg4_decode_picture_header(H263DecContext *const h)
             h->c.inter_intra_pred= 0;
             break;
         default:
-            av_unreachable("ff_msmpeg4_decode_picture_header() only used by MSMP4V1-3, WMV1");
+            av_unreachable("msmpeg4_decode_picture_header() only used by MSMP4V1-3, WMV1");
         }
         h->c.no_rounding = 1;
         if (h->c.avctx->debug & FF_DEBUG_PICT_INFO)
@@ -498,7 +498,7 @@ int ff_msmpeg4_decode_picture_header(H263DecContext *const h)
                                   ms->bit_rate <= II_BITRATE;
             break;
         default:
-            av_unreachable("ff_msmpeg4_decode_picture_header() only used by MSMP4V1-3, WMV1");
+            av_unreachable("msmpeg4_decode_picture_header() only used by MSMP4V1-3, WMV1");
         }
 
         if (h->c.avctx->debug&FF_DEBUG_PICT_INFO)
@@ -847,6 +847,8 @@ av_cold int ff_msmpeg4_decode_init(AVCodecContext *avctx)
     // We unquantize inter blocks as we parse them.
     h->c.dct_unquantize_inter = NULL;
 
+    h->decode_header = msmpeg4_decode_picture_header;
+
     ff_msmpeg4_common_init(&h->c);
 
     switch (h->c.msmpeg4_version) {

libavcodec/msmpeg4dec.h

@@ -53,7 +53,6 @@ extern const VLCElem *ff_mb_non_intra_vlc[4];
 extern VLCElem ff_inter_intra_vlc[8];
 
 int ff_msmpeg4_decode_init(AVCodecContext *avctx);
-int ff_msmpeg4_decode_picture_header(H263DecContext *const h);
 int ff_msmpeg4_decode_ext_header(H263DecContext *const h, int buf_size);
 void ff_msmpeg4_decode_motion(MSMP4DecContext *ms, int *mx_ptr, int *my_ptr);
 int ff_msmpeg4_decode_block(MSMP4DecContext *ms, int16_t * block,

libavcodec/wmv2dec.c

@@ -201,7 +201,7 @@ static int decode_ext_header(WMV2DecContext *w)
     return 0;
 }
 
-int ff_wmv2_decode_picture_header(H263DecContext *const h)
+static int wmv2_decode_picture_header(H263DecContext *const h)
 {
     int code;
 
@@ -574,6 +574,7 @@ static av_cold int wmv2_decode_init(AVCodecContext *avctx)
     if ((ret = ff_msmpeg4_decode_init(avctx)) < 0)
         return ret;
 
+    h->decode_header = wmv2_decode_picture_header;
     h->decode_mb = wmv2_decode_mb;
 
     ff_wmv2_common_init(s);

libavcodec/wmv2dec.h

@@ -24,7 +24,6 @@
 #include "mpegvideo.h"
 struct H263DecContext;
 
-int ff_wmv2_decode_picture_header(struct H263DecContext *const h);
 int ff_wmv2_decode_secondary_picture_header(struct H263DecContext *const h);
 void ff_wmv2_add_mb(MpegEncContext *s, int16_t block[6][64],
                     uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr);