+
+ s1->interlaced_frame = 0;
+ s1->top_field_first = 0;
+ header_end = &header[i+1]; // Include space
+ for(tokstart = &header[strlen(Y4M_MAGIC) + 1]; tokstart < header_end; tokstart++) {
+ if (*tokstart==0x20) continue;
+ switch (*tokstart++) {
+ case 'W': // Width. Required.
+ width = strtol(tokstart, &tokend, 10);
+ tokstart=tokend;
+ break;
+ case 'H': // Height. Required.
+ height = strtol(tokstart, &tokend, 10);
+ tokstart=tokend;
+ break;
+ case 'C': // Color space
+ if (strncmp("420jpeg",tokstart,7)==0)
+ pix_fmt = PIX_FMT_YUV420P;
+ else if (strncmp("420mpeg2",tokstart,8)==0)
+ pix_fmt = PIX_FMT_YUV420P;
+ else if (strncmp("420paldv", tokstart, 8)==0)
+ pix_fmt = PIX_FMT_YUV420P;
+ else if (strncmp("411", tokstart, 3)==0)
+ pix_fmt = PIX_FMT_YUV411P;
+ else if (strncmp("422", tokstart, 3)==0)
+ pix_fmt = PIX_FMT_YUV422P;
+ else if (strncmp("444alpha", tokstart, 8)==0) {
+ av_log(s, AV_LOG_ERROR, "Cannot handle 4:4:4:4 YUV4MPEG stream.\n");
+ return -1;
+ } else if (strncmp("444", tokstart, 3)==0)
+ pix_fmt = PIX_FMT_YUV444P;
+ else if (strncmp("mono",tokstart, 4)==0) {
+ pix_fmt = PIX_FMT_GRAY8;
+ } else {
+ av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains an unknown pixel format.\n");
+ return -1;
+ }
+ while(tokstart<header_end&&*tokstart!=0x20) tokstart++;
+ break;
+ case 'I': // Interlace type
+ switch (*tokstart++){
+ case '?':
+ break;
+ case 'p':
+ s1->interlaced_frame=0;
+ break;
+ case 't':
+ s1->interlaced_frame=1;
+ s1->top_field_first=1;
+ break;
+ case 'b':
+ s1->interlaced_frame=1;
+ s1->top_field_first=0;
+ break;
+ case 'm':
+ av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains mixed interlaced and non-interlaced frames.\n");
+ return -1;
+ default:
+ av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
+ return -1;
+ }
+ break;
+ case 'F': // Frame rate
+ sscanf(tokstart,"%d:%d",&raten,&rated); // 0:0 if unknown
+ while(tokstart<header_end&&*tokstart!=0x20) tokstart++;
+ break;
+ case 'A': // Pixel aspect
+ sscanf(tokstart,"%d:%d",&aspectn,&aspectd); // 0:0 if unknown
+ while(tokstart<header_end&&*tokstart!=0x20) tokstart++;
+ break;
+ case 'X': // Vendor extensions
+ if (strncmp("YSCSS=",tokstart,6)==0) {
+ // Older nonstandard pixel format representation
+ tokstart+=6;
+ if (strncmp("420JPEG",tokstart,7)==0)
+ alt_pix_fmt=PIX_FMT_YUV420P;
+ else if (strncmp("420MPEG2",tokstart,8)==0)
+ alt_pix_fmt=PIX_FMT_YUV420P;
+ else if (strncmp("420PALDV",tokstart,8)==0)
+ alt_pix_fmt=PIX_FMT_YUV420P;
+ else if (strncmp("411",tokstart,3)==0)
+ alt_pix_fmt=PIX_FMT_YUV411P;
+ else if (strncmp("422",tokstart,3)==0)
+ alt_pix_fmt=PIX_FMT_YUV422P;
+ else if (strncmp("444",tokstart,3)==0)
+ alt_pix_fmt=PIX_FMT_YUV444P;
+ }
+ while(tokstart<header_end&&*tokstart!=0x20) tokstart++;
+ break;
+ }
+ }
+
+ if ((width == -1) || (height == -1)) {
+ av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
+ return -1;
+ }
+
+ if (pix_fmt == PIX_FMT_NONE) {
+ if (alt_pix_fmt == PIX_FMT_NONE)
+ pix_fmt = PIX_FMT_YUV420P;
+ else
+ pix_fmt = alt_pix_fmt;
+ }
+
+ if (raten == 0 && rated == 0) {
+ // Frame rate unknown
+ raten = 25;
+ rated = 1;
+ }
+
+ if (aspectn == 0 && aspectd == 0) {
+ // Pixel aspect unknown
+ aspectd = 1;
+ }
+