FFmpeg: libavformat/yuv4mpeg.c Source File

00001 /*
00002  * YUV4MPEG format
00003  * Copyright (c) 2001, 2002, 2003 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 #include "avformat.h"
00022 #include "internal.h"
00023 #include "libavutil/pixdesc.h"
00024 
00025 #define Y4M_MAGIC "YUV4MPEG2"
00026 #define Y4M_FRAME_MAGIC "FRAME"
00027 #define Y4M_LINE_MAX 256
00028 
00029 struct frame_attributes {
00030     int interlaced_frame;
00031     int top_field_first;
00032 };
00033 
00034 #if CONFIG_YUV4MPEGPIPE_MUXER
00035 static int yuv4_generate_header(AVFormatContext *s, char* buf)
00036 {
00037     AVStream *st;
00038     int width, height;
00039     int raten, rated, aspectn, aspectd, n;
00040     char inter;
00041     const char *colorspace = "";
00042 
00043     st     = s->streams[0];
00044     width  = st->codec->width;
00045     height = st->codec->height;
00046 
00047     av_reduce(&raten, &rated, st->codec->time_base.den,
00048               st->codec->time_base.num, (1UL << 31) - 1);
00049 
00050     aspectn = st->sample_aspect_ratio.num;
00051     aspectd = st->sample_aspect_ratio.den;
00052 
00053     if (aspectn == 0 && aspectd == 1)
00054         aspectd = 0;  // 0:0 means unknown
00055 
00056     inter = 'p'; /* progressive is the default */
00057     if (st->codec->coded_frame && st->codec->coded_frame->interlaced_frame)
00058         inter = st->codec->coded_frame->top_field_first ? 't' : 'b';
00059 
00060     switch (st->codec->pix_fmt) {
00061     case AV_PIX_FMT_GRAY8:
00062         colorspace = " Cmono";
00063         break;
00064     case AV_PIX_FMT_GRAY16:
00065         colorspace = " Cmono16";
00066         break;
00067     case AV_PIX_FMT_YUV411P:
00068         colorspace = " C411 XYSCSS=411";
00069         break;
00070     case AV_PIX_FMT_YUV420P:
00071         switch (st->codec->chroma_sample_location) {
00072         case AVCHROMA_LOC_TOPLEFT: colorspace = " C420paldv XYSCSS=420PALDV"; break;
00073         case AVCHROMA_LOC_LEFT:    colorspace = " C420mpeg2 XYSCSS=420MPEG2"; break;
00074         default:                   colorspace = " C420jpeg XYSCSS=420JPEG";   break;
00075         }
00076         break;
00077     case AV_PIX_FMT_YUV422P:
00078         colorspace = " C422 XYSCSS=422";
00079         break;
00080     case AV_PIX_FMT_YUV444P:
00081         colorspace = " C444 XYSCSS=444";
00082         break;
00083     case AV_PIX_FMT_YUV420P9:
00084         colorspace = " C420p9 XYSCSS=420P9";
00085         break;
00086     case AV_PIX_FMT_YUV422P9:
00087         colorspace = " C422p9 XYSCSS=422P9";
00088         break;
00089     case AV_PIX_FMT_YUV444P9:
00090         colorspace = " C444p9 XYSCSS=444P9";
00091         break;
00092     case AV_PIX_FMT_YUV420P10:
00093         colorspace = " C420p10 XYSCSS=420P10";
00094         break;
00095     case AV_PIX_FMT_YUV422P10:
00096         colorspace = " C422p10 XYSCSS=422P10";
00097         break;
00098     case AV_PIX_FMT_YUV444P10:
00099         colorspace = " C444p10 XYSCSS=444P10";
00100         break;
00101     case AV_PIX_FMT_YUV420P12:
00102         colorspace = " C420p12 XYSCSS=420P12";
00103         break;
00104     case AV_PIX_FMT_YUV422P12:
00105         colorspace = " C422p12 XYSCSS=422P12";
00106         break;
00107     case AV_PIX_FMT_YUV444P12:
00108         colorspace = " C444p12 XYSCSS=444P12";
00109         break;
00110     case AV_PIX_FMT_YUV420P14:
00111         colorspace = " C420p14 XYSCSS=420P14";
00112         break;
00113     case AV_PIX_FMT_YUV422P14:
00114         colorspace = " C422p14 XYSCSS=422P14";
00115         break;
00116     case AV_PIX_FMT_YUV444P14:
00117         colorspace = " C444p14 XYSCSS=444P14";
00118         break;
00119     case AV_PIX_FMT_YUV420P16:
00120         colorspace = " C420p16 XYSCSS=420P16";
00121         break;
00122     case AV_PIX_FMT_YUV422P16:
00123         colorspace = " C422p16 XYSCSS=422P16";
00124         break;
00125     case AV_PIX_FMT_YUV444P16:
00126         colorspace = " C444p16 XYSCSS=444P16";
00127         break;
00128     }
00129 
00130     /* construct stream header, if this is the first frame */
00131     n = snprintf(buf, Y4M_LINE_MAX, "%s W%d H%d F%d:%d I%c A%d:%d%s\n",
00132                  Y4M_MAGIC, width, height, raten, rated, inter,
00133                  aspectn, aspectd, colorspace);
00134 
00135     return n;
00136 }
00137 
00138 static int yuv4_write_packet(AVFormatContext *s, AVPacket *pkt)
00139 {
00140     AVStream *st = s->streams[pkt->stream_index];
00141     AVIOContext *pb = s->pb;
00142     AVPicture *picture, picture_tmp;
00143     int* first_pkt = s->priv_data;
00144     int width, height, h_chroma_shift, v_chroma_shift;
00145     int i;
00146     char buf2[Y4M_LINE_MAX + 1];
00147     char buf1[20];
00148     uint8_t *ptr, *ptr1, *ptr2;
00149 
00150     memcpy(&picture_tmp, pkt->data, sizeof(AVPicture));
00151     picture = &picture_tmp;
00152 
00153     /* for the first packet we have to output the header as well */
00154     if (*first_pkt) {
00155         *first_pkt = 0;
00156         if (yuv4_generate_header(s, buf2) < 0) {
00157             av_log(s, AV_LOG_ERROR,
00158                    "Error. YUV4MPEG stream header write failed.\n");
00159             return AVERROR(EIO);
00160         } else {
00161             avio_write(pb, buf2, strlen(buf2));
00162         }
00163     }
00164 
00165     /* construct frame header */
00166 
00167     snprintf(buf1, sizeof(buf1), "%s\n", Y4M_FRAME_MAGIC);
00168     avio_write(pb, buf1, strlen(buf1));
00169 
00170     width  = st->codec->width;
00171     height = st->codec->height;
00172 
00173     ptr = picture->data[0];
00174 
00175     switch (st->codec->pix_fmt) {
00176     case AV_PIX_FMT_GRAY8:
00177     case AV_PIX_FMT_YUV411P:
00178     case AV_PIX_FMT_YUV420P:
00179     case AV_PIX_FMT_YUV422P:
00180     case AV_PIX_FMT_YUV444P:
00181         break;
00182     case AV_PIX_FMT_GRAY16:
00183     case AV_PIX_FMT_YUV420P9:
00184     case AV_PIX_FMT_YUV422P9:
00185     case AV_PIX_FMT_YUV444P9:
00186     case AV_PIX_FMT_YUV420P10:
00187     case AV_PIX_FMT_YUV422P10:
00188     case AV_PIX_FMT_YUV444P10:
00189     case AV_PIX_FMT_YUV420P12:
00190     case AV_PIX_FMT_YUV422P12:
00191     case AV_PIX_FMT_YUV444P12:
00192     case AV_PIX_FMT_YUV420P14:
00193     case AV_PIX_FMT_YUV422P14:
00194     case AV_PIX_FMT_YUV444P14:
00195     case AV_PIX_FMT_YUV420P16:
00196     case AV_PIX_FMT_YUV422P16:
00197     case AV_PIX_FMT_YUV444P16:
00198         width *= 2;
00199         break;
00200     default:
00201         av_log(s, AV_LOG_ERROR, "The pixel format '%s' is not supported.\n",
00202                av_get_pix_fmt_name(st->codec->pix_fmt));
00203         return AVERROR(EINVAL);
00204     }
00205 
00206     for (i = 0; i < height; i++) {
00207         avio_write(pb, ptr, width);
00208         ptr += picture->linesize[0];
00209     }
00210 
00211     if (st->codec->pix_fmt != AV_PIX_FMT_GRAY8 &&
00212         st->codec->pix_fmt != AV_PIX_FMT_GRAY16) {
00213         // Adjust for smaller Cb and Cr planes
00214         avcodec_get_chroma_sub_sample(st->codec->pix_fmt, &h_chroma_shift,
00215                                       &v_chroma_shift);
00216         width  >>= h_chroma_shift;
00217         height >>= v_chroma_shift;
00218 
00219         ptr1 = picture->data[1];
00220         ptr2 = picture->data[2];
00221         for (i = 0; i < height; i++) {     /* Cb */
00222             avio_write(pb, ptr1, width);
00223             ptr1 += picture->linesize[1];
00224         }
00225         for (i = 0; i < height; i++) {     /* Cr */
00226             avio_write(pb, ptr2, width);
00227             ptr2 += picture->linesize[2];
00228         }
00229     }
00230 
00231     avio_flush(pb);
00232     return 0;
00233 }
00234 
00235 static int yuv4_write_header(AVFormatContext *s)
00236 {
00237     int *first_pkt = s->priv_data;
00238 
00239     if (s->nb_streams != 1)
00240         return AVERROR(EIO);
00241 
00242     if (s->streams[0]->codec->codec_id != AV_CODEC_ID_RAWVIDEO) {
00243         av_log(s, AV_LOG_ERROR, "ERROR: Only rawvideo supported.\n");
00244         return AVERROR_INVALIDDATA;
00245     }
00246 
00247     switch (s->streams[0]->codec->pix_fmt) {
00248     case AV_PIX_FMT_YUV411P:
00249         av_log(s, AV_LOG_WARNING, "Warning: generating rarely used 4:1:1 YUV "
00250                "stream, some mjpegtools might not work.\n");
00251         break;
00252     case AV_PIX_FMT_GRAY8:
00253     case AV_PIX_FMT_GRAY16:
00254     case AV_PIX_FMT_YUV420P:
00255     case AV_PIX_FMT_YUV422P:
00256     case AV_PIX_FMT_YUV444P:
00257         break;
00258     case AV_PIX_FMT_YUV420P9:
00259     case AV_PIX_FMT_YUV422P9:
00260     case AV_PIX_FMT_YUV444P9:
00261     case AV_PIX_FMT_YUV420P10:
00262     case AV_PIX_FMT_YUV422P10:
00263     case AV_PIX_FMT_YUV444P10:
00264     case AV_PIX_FMT_YUV420P12:
00265     case AV_PIX_FMT_YUV422P12:
00266     case AV_PIX_FMT_YUV444P12:
00267     case AV_PIX_FMT_YUV420P14:
00268     case AV_PIX_FMT_YUV422P14:
00269     case AV_PIX_FMT_YUV444P14:
00270     case AV_PIX_FMT_YUV420P16:
00271     case AV_PIX_FMT_YUV422P16:
00272     case AV_PIX_FMT_YUV444P16:
00273         if (s->streams[0]->codec->strict_std_compliance >= FF_COMPLIANCE_NORMAL) {
00274             av_log(s, AV_LOG_ERROR, "'%s' is not a official yuv4mpegpipe pixel format. "
00275                    "Use '-strict -1' to encode to this pixel format.\n",
00276                    av_get_pix_fmt_name(s->streams[0]->codec->pix_fmt));
00277             return AVERROR(EINVAL);
00278         }
00279         av_log(s, AV_LOG_WARNING, "Warning: generating non standart YUV stream. "
00280                "Mjpegtools will not work.\n");
00281         break;
00282     default:
00283         av_log(s, AV_LOG_ERROR, "ERROR: yuv4mpeg can only handle "
00284                "yuv444p, yuv422p, yuv420p, yuv411p and gray8 pixel formats. "
00285                "And using 'strict -1' also yuv444p9, yuv422p9, yuv420p9, "
00286                "yuv444p10, yuv422p10, yuv420p10, "
00287                "yuv444p12, yuv422p12, yuv420p12, "
00288                "yuv444p14, yuv422p14, yuv420p14, "
00289                "yuv444p16, yuv422p16, yuv420p16 "
00290                "and gray16 pixel formats. "
00291                "Use -pix_fmt to select one.\n");
00292         return AVERROR(EIO);
00293     }
00294 
00295     *first_pkt = 1;
00296     return 0;
00297 }
00298 
00299 AVOutputFormat ff_yuv4mpegpipe_muxer = {
00300     .name              = "yuv4mpegpipe",
00301     .long_name         = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
00302     .extensions        = "y4m",
00303     .priv_data_size    = sizeof(int),
00304     .audio_codec       = AV_CODEC_ID_NONE,
00305     .video_codec       = AV_CODEC_ID_RAWVIDEO,
00306     .write_header      = yuv4_write_header,
00307     .write_packet      = yuv4_write_packet,
00308     .flags             = AVFMT_RAWPICTURE,
00309 };
00310 #endif
00311 
00312 /* Header size increased to allow room for optional flags */
00313 #define MAX_YUV4_HEADER 80
00314 #define MAX_FRAME_HEADER 80
00315 
00316 static int yuv4_read_header(AVFormatContext *s)
00317 {
00318     char header[MAX_YUV4_HEADER + 10];  // Include headroom for
00319                                         // the longest option
00320     char *tokstart, *tokend, *header_end;
00321     int i;
00322     AVIOContext *pb = s->pb;
00323     int width = -1, height  = -1, raten   = 0,
00324         rated =  0, aspectn =  0, aspectd = 0;
00325     enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE, alt_pix_fmt = AV_PIX_FMT_NONE;
00326     enum AVChromaLocation chroma_sample_location = AVCHROMA_LOC_UNSPECIFIED;
00327     AVStream *st;
00328     struct frame_attributes *s1 = s->priv_data;
00329 
00330     for (i = 0; i < MAX_YUV4_HEADER; i++) {
00331         header[i] = avio_r8(pb);
00332         if (header[i] == '\n') {
00333             header[i + 1] = 0x20;  // Add a space after last option.
00334                                    // Makes parsing "444" vs "444alpha" easier.
00335             header[i + 2] = 0;
00336             break;
00337         }
00338     }
00339     if (i == MAX_YUV4_HEADER)
00340         return -1;
00341     if (strncmp(header, Y4M_MAGIC, strlen(Y4M_MAGIC)))
00342         return -1;
00343 
00344     s1->interlaced_frame = 0;
00345     s1->top_field_first = 0;
00346     header_end = &header[i + 1]; // Include space
00347     for (tokstart = &header[strlen(Y4M_MAGIC) + 1];
00348          tokstart < header_end; tokstart++) {
00349         if (*tokstart == 0x20)
00350             continue;
00351         switch (*tokstart++) {
00352         case 'W': // Width. Required.
00353             width    = strtol(tokstart, &tokend, 10);
00354             tokstart = tokend;
00355             break;
00356         case 'H': // Height. Required.
00357             height   = strtol(tokstart, &tokend, 10);
00358             tokstart = tokend;
00359             break;
00360         case 'C': // Color space
00361             if (strncmp("420jpeg", tokstart, 7) == 0) {
00362                 pix_fmt = AV_PIX_FMT_YUV420P;
00363                 chroma_sample_location = AVCHROMA_LOC_CENTER;
00364             } else if (strncmp("420mpeg2", tokstart, 8) == 0) {
00365                 pix_fmt = AV_PIX_FMT_YUV420P;
00366                 chroma_sample_location = AVCHROMA_LOC_LEFT;
00367             } else if (strncmp("420paldv", tokstart, 8) == 0) {
00368                 pix_fmt = AV_PIX_FMT_YUV420P;
00369                 chroma_sample_location = AVCHROMA_LOC_TOPLEFT;
00370             } else if (strncmp("420p16", tokstart, 6) == 0) {
00371                 pix_fmt = AV_PIX_FMT_YUV420P16;
00372             } else if (strncmp("422p16", tokstart, 6) == 0) {
00373                 pix_fmt = AV_PIX_FMT_YUV422P16;
00374             } else if (strncmp("444p16", tokstart, 6) == 0) {
00375                 pix_fmt = AV_PIX_FMT_YUV444P16;
00376             } else if (strncmp("420p14", tokstart, 6) == 0) {
00377                 pix_fmt = AV_PIX_FMT_YUV420P14;
00378             } else if (strncmp("422p14", tokstart, 6) == 0) {
00379                 pix_fmt = AV_PIX_FMT_YUV422P14;
00380             } else if (strncmp("444p14", tokstart, 6) == 0) {
00381                 pix_fmt = AV_PIX_FMT_YUV444P14;
00382             } else if (strncmp("420p12", tokstart, 6) == 0) {
00383                 pix_fmt = AV_PIX_FMT_YUV420P12;
00384             } else if (strncmp("422p12", tokstart, 6) == 0) {
00385                 pix_fmt = AV_PIX_FMT_YUV422P12;
00386             } else if (strncmp("444p12", tokstart, 6) == 0) {
00387                 pix_fmt = AV_PIX_FMT_YUV444P12;
00388             } else if (strncmp("420p10", tokstart, 6) == 0) {
00389                 pix_fmt = AV_PIX_FMT_YUV420P10;
00390             } else if (strncmp("422p10", tokstart, 6) == 0) {
00391                 pix_fmt = AV_PIX_FMT_YUV422P10;
00392             } else if (strncmp("444p10", tokstart, 6) == 0) {
00393                 pix_fmt = AV_PIX_FMT_YUV444P10;
00394             } else if (strncmp("420p9", tokstart, 5) == 0) {
00395                 pix_fmt = AV_PIX_FMT_YUV420P9;
00396             } else if (strncmp("422p9", tokstart, 5) == 0) {
00397                 pix_fmt = AV_PIX_FMT_YUV422P9;
00398             } else if (strncmp("444p9", tokstart, 5) == 0) {
00399                 pix_fmt = AV_PIX_FMT_YUV444P9;
00400             } else if (strncmp("420", tokstart, 3) == 0) {
00401                 pix_fmt = AV_PIX_FMT_YUV420P;
00402                 chroma_sample_location = AVCHROMA_LOC_CENTER;
00403             } else if (strncmp("411", tokstart, 3) == 0) {
00404                 pix_fmt = AV_PIX_FMT_YUV411P;
00405             } else if (strncmp("422", tokstart, 3) == 0) {
00406                 pix_fmt = AV_PIX_FMT_YUV422P;
00407             } else if (strncmp("444alpha", tokstart, 8) == 0 ) {
00408                 av_log(s, AV_LOG_ERROR, "Cannot handle 4:4:4:4 "
00409                        "YUV4MPEG stream.\n");
00410                 return -1;
00411             } else if (strncmp("444", tokstart, 3) == 0) {
00412                 pix_fmt = AV_PIX_FMT_YUV444P;
00413             } else if (strncmp("mono16", tokstart, 6) == 0) {
00414                 pix_fmt = AV_PIX_FMT_GRAY16;
00415             } else if (strncmp("mono", tokstart, 4) == 0) {
00416                 pix_fmt = AV_PIX_FMT_GRAY8;
00417             } else {
00418                 av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains an unknown "
00419                        "pixel format.\n");
00420                 return -1;
00421             }
00422             while (tokstart < header_end && *tokstart != 0x20)
00423                 tokstart++;
00424             break;
00425         case 'I': // Interlace type
00426             switch (*tokstart++){
00427             case '?':
00428                 break;
00429             case 'p':
00430                 s1->interlaced_frame = 0;
00431                 break;
00432             case 't':
00433                 s1->interlaced_frame = 1;
00434                 s1->top_field_first = 1;
00435                 break;
00436             case 'b':
00437                 s1->interlaced_frame = 1;
00438                 s1->top_field_first = 0;
00439                 break;
00440             case 'm':
00441                 av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains mixed "
00442                        "interlaced and non-interlaced frames.\n");
00443                 return -1;
00444             default:
00445                 av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
00446                 return -1;
00447             }
00448             break;
00449         case 'F': // Frame rate
00450             sscanf(tokstart, "%d:%d", &raten, &rated); // 0:0 if unknown
00451             while (tokstart < header_end && *tokstart != 0x20)
00452                 tokstart++;
00453             break;
00454         case 'A': // Pixel aspect
00455             sscanf(tokstart, "%d:%d", &aspectn, &aspectd); // 0:0 if unknown
00456             while (tokstart < header_end && *tokstart != 0x20)
00457                 tokstart++;
00458             break;
00459         case 'X': // Vendor extensions
00460             if (strncmp("YSCSS=", tokstart, 6) == 0) {
00461                 // Older nonstandard pixel format representation
00462                 tokstart += 6;
00463                 if (strncmp("420JPEG", tokstart, 7) == 0)
00464                     alt_pix_fmt = AV_PIX_FMT_YUV420P;
00465                 else if (strncmp("420MPEG2", tokstart, 8) == 0)
00466                     alt_pix_fmt = AV_PIX_FMT_YUV420P;
00467                 else if (strncmp("420PALDV", tokstart, 8) == 0)
00468                     alt_pix_fmt = AV_PIX_FMT_YUV420P;
00469                 else if (strncmp("420P9", tokstart, 5) == 0)
00470                     alt_pix_fmt = AV_PIX_FMT_YUV420P9;
00471                 else if (strncmp("422P9", tokstart, 5) == 0)
00472                     alt_pix_fmt = AV_PIX_FMT_YUV422P9;
00473                 else if (strncmp("444P9", tokstart, 5) == 0)
00474                     alt_pix_fmt = AV_PIX_FMT_YUV444P9;
00475                 else if (strncmp("420P10", tokstart, 6) == 0)
00476                     alt_pix_fmt = AV_PIX_FMT_YUV420P10;
00477                 else if (strncmp("422P10", tokstart, 6) == 0)
00478                     alt_pix_fmt = AV_PIX_FMT_YUV422P10;
00479                 else if (strncmp("444P10", tokstart, 6) == 0)
00480                     alt_pix_fmt = AV_PIX_FMT_YUV444P10;
00481                 else if (strncmp("420P12", tokstart, 6) == 0)
00482                     alt_pix_fmt = AV_PIX_FMT_YUV420P12;
00483                 else if (strncmp("422P12", tokstart, 6) == 0)
00484                     alt_pix_fmt = AV_PIX_FMT_YUV422P12;
00485                 else if (strncmp("444P12", tokstart, 6) == 0)
00486                     alt_pix_fmt = AV_PIX_FMT_YUV444P12;
00487                 else if (strncmp("420P14", tokstart, 6) == 0)
00488                     alt_pix_fmt = AV_PIX_FMT_YUV420P14;
00489                 else if (strncmp("422P14", tokstart, 6) == 0)
00490                     alt_pix_fmt = AV_PIX_FMT_YUV422P14;
00491                 else if (strncmp("444P14", tokstart, 6) == 0)
00492                     alt_pix_fmt = AV_PIX_FMT_YUV444P14;
00493                 else if (strncmp("420P16", tokstart, 6) == 0)
00494                     alt_pix_fmt = AV_PIX_FMT_YUV420P16;
00495                 else if (strncmp("422P16", tokstart, 6) == 0)
00496                     alt_pix_fmt = AV_PIX_FMT_YUV422P16;
00497                 else if (strncmp("444P16", tokstart, 6) == 0)
00498                     alt_pix_fmt = AV_PIX_FMT_YUV444P16;
00499                 else if (strncmp("411", tokstart, 3) == 0)
00500                     alt_pix_fmt = AV_PIX_FMT_YUV411P;
00501                 else if (strncmp("422", tokstart, 3) == 0)
00502                     alt_pix_fmt = AV_PIX_FMT_YUV422P;
00503                 else if (strncmp("444", tokstart, 3) == 0)
00504                     alt_pix_fmt = AV_PIX_FMT_YUV444P;
00505             }
00506             while (tokstart < header_end && *tokstart != 0x20)
00507                 tokstart++;
00508             break;
00509         }
00510     }
00511 
00512     if (width == -1 || height == -1) {
00513         av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
00514         return -1;
00515     }
00516 
00517     if (pix_fmt == AV_PIX_FMT_NONE) {
00518         if (alt_pix_fmt == AV_PIX_FMT_NONE)
00519             pix_fmt = AV_PIX_FMT_YUV420P;
00520         else
00521             pix_fmt = alt_pix_fmt;
00522     }
00523 
00524     if (raten <= 0 || rated <= 0) {
00525         // Frame rate unknown
00526         raten = 25;
00527         rated = 1;
00528     }
00529 
00530     if (aspectn == 0 && aspectd == 0) {
00531         // Pixel aspect unknown
00532         aspectd = 1;
00533     }
00534 
00535     st = avformat_new_stream(s, NULL);
00536     if (!st)
00537         return AVERROR(ENOMEM);
00538     st->codec->width  = width;
00539     st->codec->height = height;
00540     av_reduce(&raten, &rated, raten, rated, (1UL << 31) - 1);
00541     avpriv_set_pts_info(st, 64, rated, raten);
00542     st->codec->pix_fmt                = pix_fmt;
00543     st->codec->codec_type             = AVMEDIA_TYPE_VIDEO;
00544     st->codec->codec_id               = AV_CODEC_ID_RAWVIDEO;
00545     st->sample_aspect_ratio           = (AVRational){ aspectn, aspectd };
00546     st->codec->chroma_sample_location = chroma_sample_location;
00547 
00548     return 0;
00549 }
00550 
00551 static int yuv4_read_packet(AVFormatContext *s, AVPacket *pkt)
00552 {
00553     int i;
00554     char header[MAX_FRAME_HEADER+1];
00555     int packet_size, width, height, ret;
00556     AVStream *st = s->streams[0];
00557     struct frame_attributes *s1 = s->priv_data;
00558 
00559     for (i = 0; i < MAX_FRAME_HEADER; i++) {
00560         header[i] = avio_r8(s->pb);
00561         if (header[i] == '\n') {
00562             header[i + 1] = 0;
00563             break;
00564         }
00565     }
00566     if (s->pb->error)
00567         return s->pb->error;
00568     else if (s->pb->eof_reached)
00569         return AVERROR_EOF;
00570     else if (i == MAX_FRAME_HEADER)
00571         return AVERROR_INVALIDDATA;
00572 
00573     if (strncmp(header, Y4M_FRAME_MAGIC, strlen(Y4M_FRAME_MAGIC)))
00574         return AVERROR_INVALIDDATA;
00575 
00576     width  = st->codec->width;
00577     height = st->codec->height;
00578 
00579     packet_size = avpicture_get_size(st->codec->pix_fmt, width, height);
00580     if (packet_size < 0)
00581         return packet_size;
00582 
00583     ret = av_get_packet(s->pb, pkt, packet_size);
00584     if (ret < 0)
00585         return ret;
00586     else if (ret != packet_size)
00587         return s->pb->eof_reached ? AVERROR_EOF : AVERROR(EIO);
00588 
00589     if (st->codec->coded_frame) {
00590         st->codec->coded_frame->interlaced_frame = s1->interlaced_frame;
00591         st->codec->coded_frame->top_field_first  = s1->top_field_first;
00592     }
00593 
00594     pkt->stream_index = 0;
00595     return 0;
00596 }
00597 
00598 static int yuv4_probe(AVProbeData *pd)
00599 {
00600     /* check file header */
00601     if (strncmp(pd->buf, Y4M_MAGIC, sizeof(Y4M_MAGIC) - 1) == 0)
00602         return AVPROBE_SCORE_MAX;
00603     else
00604         return 0;
00605 }
00606 
00607 #if CONFIG_YUV4MPEGPIPE_DEMUXER
00608 AVInputFormat ff_yuv4mpegpipe_demuxer = {
00609     .name           = "yuv4mpegpipe",
00610     .long_name      = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
00611     .priv_data_size = sizeof(struct frame_attributes),
00612     .read_probe     = yuv4_probe,
00613     .read_header    = yuv4_read_header,
00614     .read_packet    = yuv4_read_packet,
00615     .extensions     = "y4m",
00616 };
00617 #endif