SVCD scan offset stuff

Originally committed as revision 2660 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -121,6 +121,7 @@ static int use_aiv = 0;
 static int use_umv = 0;
 static int use_alt_scan = 0;
 static int use_trell = 0;
+static int use_scan_offset = 0;
 static int do_deinterlace = 0;
 static int do_interlace_dct = 0;
 static int do_interlace_me = 0;
@@ -2399,6 +2400,9 @@ static void opt_output_file(const char *filename)
            	if (use_trell) {
                     video_enc->flags |= CODEC_FLAG_TRELLIS_QUANT;
                 }
+           	if (use_scan_offset) {
+                    video_enc->flags |= CODEC_FLAG_SVCD_SCAN_OFFSET;
+                }
                 if (b_frames) {
                     video_enc->max_b_frames = b_frames;
                     video_enc->b_frame_strategy = 0;
@@ -2906,6 +2910,7 @@ static void opt_target(const char *arg)
         video_rc_max_rate = 2516000;
         video_rc_min_rate = 0; //1145000;
         video_rc_buffer_size = 224*1024*8;
+        use_scan_offset = 1;
 
         audio_bit_rate = 224000;
         audio_sample_rate = 44100;
@@ -3034,6 +3039,7 @@ const OptionDef options[] = {
     { "umv", OPT_BOOL | OPT_EXPERT | OPT_VIDEO, {(void*)&use_umv}, "enable Unlimited Motion Vector (h263+)" },
     { "alt", OPT_BOOL | OPT_EXPERT | OPT_VIDEO, {(void*)&use_alt_scan}, "enable alternate scantable (mpeg2)" },
     { "trell", OPT_BOOL | OPT_EXPERT | OPT_VIDEO, {(void*)&use_trell}, "enable trellis quantization" },
+    { "scan_offset", OPT_BOOL | OPT_EXPERT | OPT_VIDEO, {(void*)&use_scan_offset}, "enable SVCD Scan Offset placeholder" },
     { "intra_matrix", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_intra_matrix}, "specify intra matrix coeffs", "matrix" },
     { "inter_matrix", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_inter_matrix}, "specify inter matrix coeffs", "matrix" },
     { "top", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_top_field_first}, "top=1/bottom=0/auto=-1 field first", "" },

libavcodec/avcodec.h

@@ -267,6 +267,7 @@ static const __attribute__((unused)) int Motion_Est_QTab[] =
 #define CODEC_FLAG_LOOP_FILTER    0x00000800 ///< loop filter
 #define CODEC_FLAG_H263P_SLICE_STRUCT 0x10000000
 #define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
+#define CODEC_FLAG_SVCD_SCAN_OFFSET 0x40000000 ///< will reserve space for SVCD scan offset user data
 /* Unsupported options :
  * 		Syntax Arithmetic coding (SAC)
  * 		Reference Picture Selection

libavcodec/mpeg12.c

@@ -473,6 +473,14 @@ void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
         put_bits(&s->pb, 1, s->progressive_frame);
         put_bits(&s->pb, 1, 0); //composite_display_flag
     }
+    if(s->flags & CODEC_FLAG_SVCD_SCAN_OFFSET){
+        int i;
+
+        put_header(s, USER_START_CODE);
+        for(i=0; i<sizeof(svcd_scan_offset_placeholder); i++){
+            put_bits(&s->pb, 8, svcd_scan_offset_placeholder[i]);
+        }
+    }
     
     s->mb_y=0;
     ff_mpeg1_encode_slice_header(s);
@@ -1809,7 +1817,7 @@ 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;
+    int bit_rate_ext;
     int frame_rate_ext_n, frame_rate_ext_d;
     int level, profile;
 

libavcodec/mpeg12data.h

@@ -433,3 +433,10 @@ static const AVRational mpeg2_aspect[16]={
     {0,1},
 };
 
+static const uint8_t svcd_scan_offset_placeholder[14]={
+    0x10, 0x0E,
+    0x00, 0x80, 0x81,
+    0x00, 0x80, 0x81,
+    0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff,
+};