mpeg1&2 aspect decoding
authorMichael Niedermayer <michaelni@gmx.at>
Fri, 6 Dec 2002 16:04:30 +0000 (16:04 +0000)
committerMichael Niedermayer <michaelni@gmx.at>
Fri, 6 Dec 2002 16:04:30 +0000 (16:04 +0000)
Originally committed as revision 1318 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpeg12.c
libavcodec/mpeg12data.h

index e625a726247f27ef7115a0f7734528e9124be48e..51ebc950dc6d1e95e73aa62a504064c77c87cbdc 100644 (file)
@@ -1431,8 +1431,9 @@ static int mpeg1_decode_picture(AVCodecContext *avctx,
 static void mpeg_decode_sequence_extension(MpegEncContext *s)
 {
     int horiz_size_ext, vert_size_ext;
-    int bit_rate_ext, vbv_buf_ext, low_delay;
+    int bit_rate_ext, vbv_buf_ext;
     int frame_rate_ext_n, frame_rate_ext_d;
+    float aspect;
 
     skip_bits(&s->gb, 8); /* profil and level */
     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */
@@ -1445,7 +1446,7 @@ static void mpeg_decode_sequence_extension(MpegEncContext *s)
     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
     skip_bits1(&s->gb); /* marker */
     vbv_buf_ext = get_bits(&s->gb, 8);
-    low_delay = get_bits1(&s->gb);
+    s->low_delay = get_bits1(&s->gb);
     frame_rate_ext_n = get_bits(&s->gb, 2);
     frame_rate_ext_d = get_bits(&s->gb, 5);
     if (frame_rate_ext_d >= 1)
@@ -1453,6 +1454,10 @@ static void mpeg_decode_sequence_extension(MpegEncContext *s)
     dprintf("sequence extension\n");
     s->mpeg2 = 1;
     s->avctx->sub_id = 2; /* indicates mpeg2 found */
+
+    aspect= mpeg2_aspect[s->aspect_ratio_info];
+    if(aspect>0.0)      s->avctx->aspect_ratio= s->width/(aspect*s->height);
+    else if(aspect<0.0) s->avctx->aspect_ratio= -1.0/aspect;
 }
 
 static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
@@ -1706,12 +1711,18 @@ static int mpeg1_decode_sequence(AVCodecContext *avctx,
     Mpeg1Context *s1 = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;
     int width, height, i, v, j;
+    float aspect;
 
     init_get_bits(&s->gb, buf, buf_size);
 
     width = get_bits(&s->gb, 12);
     height = get_bits(&s->gb, 12);
-    skip_bits(&s->gb, 4);
+    s->aspect_ratio_info= get_bits(&s->gb, 4);
+    if(!s->mpeg2){
+        aspect= mpeg1_aspect[s->aspect_ratio_info];
+        if(aspect!=0.0) avctx->aspect_ratio= width/(aspect*height);
+    }
+
     s->frame_rate_index = get_bits(&s->gb, 4);
     if (s->frame_rate_index == 0)
         return -1;
@@ -1896,15 +1907,16 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
                                           s->buffer, input_size);
                     break;
                 default:
-                    /* skip b frames if we dont have reference frames */
-                    if(s2->last_picture.data[0]==NULL && s2->pict_type==B_TYPE) break;
-                    /* skip b frames if we are in a hurry */
-                    if(avctx->hurry_up && s2->pict_type==B_TYPE) break;
-                    /* skip everything if we are in a hurry>=5 */
-                    if(avctx->hurry_up>=5) break;
-
                     if (start_code >= SLICE_MIN_START_CODE &&
                         start_code <= SLICE_MAX_START_CODE) {
+                        
+                        /* skip b frames if we dont have reference frames */
+                        if(s2->last_picture.data[0]==NULL && s2->pict_type==B_TYPE) break;
+                        /* skip b frames if we are in a hurry */
+                        if(avctx->hurry_up && s2->pict_type==B_TYPE) break;
+                        /* skip everything if we are in a hurry>=5 */
+                        if(avctx->hurry_up>=5) break;
+
                         ret = mpeg_decode_slice(avctx, picture,
                                                 start_code, s->buffer, input_size);
                         if (ret == DECODE_SLICE_EOP) {
index a1a7166beb3bcc5bf59a8ee1c7edd514bb0e003d..8bf063ec1b878a45c4dff721337943d574da9a4e 100644 (file)
@@ -411,4 +411,32 @@ UINT8 ff_mpeg1_dc_scale_table[128]={ // MN: mpeg2 really can have such large qsc
     8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
 };
 
+static const float mpeg1_aspect[16]={
+    0.0000,
+    1.0000,
+    0.6735,
+    0.7031,
+    
+    0.7615,
+    0.8055,
+    0.8437,
+    0.8935,
+
+    0.9157,
+    0.9815,
+    1.0255,
+    1.0695,
+
+    1.0950,
+    1.1575,
+    1.2015,
+};
+
+static const float mpeg2_aspect[16]={
+    0,
+    1.0,
+    -3.0/4.0,
+    -9.0/16.0,
+    -1.0/2.21,
+};