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 PIX_FMT_GRAY8:
00062         colorspace = " Cmono";
00063         break;
00064     case PIX_FMT_GRAY16:
00065         colorspace = " Cmono16";
00066         break;
00067     case PIX_FMT_YUV411P:
00068         colorspace = " C411 XYSCSS=411";
00069         break;
00070     case 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 PIX_FMT_YUV422P:
00078         colorspace = " C422 XYSCSS=422";
00079         break;
00080     case PIX_FMT_YUV444P:
00081         colorspace = " C444 XYSCSS=444";
00082         break;
00083     case PIX_FMT_YUV420P9:
00084         colorspace = " C420p9 XYSCSS=420P9";
00085         break;
00086     case PIX_FMT_YUV422P9:
00087         colorspace = " C422p9 XYSCSS=422P9";
00088         break;
00089     case PIX_FMT_YUV444P9:
00090         colorspace = " C444p9 XYSCSS=444P9";
00091         break;
00092     case PIX_FMT_YUV420P10:
00093         colorspace = " C420p10 XYSCSS=420P10";
00094         break;
00095     case PIX_FMT_YUV422P10:
00096         colorspace = " C422p10 XYSCSS=422P10";
00097         break;
00098     case PIX_FMT_YUV444P10:
00099         colorspace = " C444p10 XYSCSS=444P10";
00100         break;
00101     case PIX_FMT_YUV420P16:
00102         colorspace = " C420p16 XYSCSS=420P16";
00103         break;
00104     case PIX_FMT_YUV422P16:
00105         colorspace = " C422p16 XYSCSS=422P16";
00106         break;
00107     case PIX_FMT_YUV444P16:
00108         colorspace = " C444p16 XYSCSS=444P16";
00109         break;
00110     }
00111 
00112     /* construct stream header, if this is the first frame */
00113     n = snprintf(buf, Y4M_LINE_MAX, "%s W%d H%d F%d:%d I%c A%d:%d%s\n",
00114                  Y4M_MAGIC, width, height, raten, rated, inter,
00115                  aspectn, aspectd, colorspace);
00116 
00117     return n;
00118 }
00119 
00120 static int yuv4_write_packet(AVFormatContext *s, AVPacket *pkt)
00121 {
00122     AVStream *st = s->streams[pkt->stream_index];
00123     AVIOContext *pb = s->pb;
00124     AVPicture *picture, picture_tmp;
00125     int* first_pkt = s->priv_data;
00126     int width, height, h_chroma_shift, v_chroma_shift;
00127     int i;
00128     char buf2[Y4M_LINE_MAX + 1];
00129     char buf1[20];
00130     uint8_t *ptr, *ptr1, *ptr2;
00131 
00132     memcpy(&picture_tmp, pkt->data, sizeof(AVPicture));
00133     picture = &picture_tmp;
00134 
00135     /* for the first packet we have to output the header as well */
00136     if (*first_pkt) {
00137         *first_pkt = 0;
00138         if (yuv4_generate_header(s, buf2) < 0) {
00139             av_log(s, AV_LOG_ERROR,
00140                    "Error. YUV4MPEG stream header write failed.\n");
00141             return AVERROR(EIO);
00142         } else {
00143             avio_write(pb, buf2, strlen(buf2));
00144         }
00145     }
00146 
00147     /* construct frame header */
00148 
00149     snprintf(buf1, sizeof(buf1), "%s\n", Y4M_FRAME_MAGIC);
00150     avio_write(pb, buf1, strlen(buf1));
00151 
00152     width  = st->codec->width;
00153     height = st->codec->height;
00154 
00155     ptr = picture->data[0];
00156 
00157     switch (st->codec->pix_fmt) {
00158     case PIX_FMT_GRAY8:
00159     case PIX_FMT_YUV411P:
00160     case PIX_FMT_YUV420P:
00161     case PIX_FMT_YUV422P:
00162     case PIX_FMT_YUV444P:
00163         break;
00164     case PIX_FMT_GRAY16:
00165     case PIX_FMT_YUV420P9:
00166     case PIX_FMT_YUV422P9:
00167     case PIX_FMT_YUV444P9:
00168     case PIX_FMT_YUV420P10:
00169     case PIX_FMT_YUV422P10:
00170     case PIX_FMT_YUV444P10:
00171     case PIX_FMT_YUV420P16:
00172     case PIX_FMT_YUV422P16:
00173     case PIX_FMT_YUV444P16:
00174         width *= 2;
00175         break;
00176     default:
00177         av_log(s, AV_LOG_ERROR, "The pixel format '%s' is not supported.\n",
00178                av_get_pix_fmt_name(st->codec->pix_fmt));
00179         return AVERROR(EINVAL);
00180     }
00181 
00182     for (i = 0; i < height; i++) {
00183         avio_write(pb, ptr, width);
00184         ptr += picture->linesize[0];
00185     }
00186 
00187     if (st->codec->pix_fmt != PIX_FMT_GRAY8 &&
00188         st->codec->pix_fmt != PIX_FMT_GRAY16) {
00189         // Adjust for smaller Cb and Cr planes
00190         avcodec_get_chroma_sub_sample(st->codec->pix_fmt, &h_chroma_shift,
00191                                       &v_chroma_shift);
00192         width  >>= h_chroma_shift;
00193         height >>= v_chroma_shift;
00194 
00195         ptr1 = picture->data[1];
00196         ptr2 = picture->data[2];
00197         for (i = 0; i < height; i++) {     /* Cb */
00198             avio_write(pb, ptr1, width);
00199             ptr1 += picture->linesize[1];
00200         }
00201         for (i = 0; i < height; i++) {     /* Cr */
00202             avio_write(pb, ptr2, width);
00203             ptr2 += picture->linesize[2];
00204         }
00205     }
00206 
00207     avio_flush(pb);
00208     return 0;
00209 }
00210 
00211 static int yuv4_write_header(AVFormatContext *s)
00212 {
00213     int *first_pkt = s->priv_data;
00214 
00215     if (s->nb_streams != 1)
00216         return AVERROR(EIO);
00217 
00218     if (s->streams[0]->codec->codec_id != AV_CODEC_ID_RAWVIDEO) {
00219         av_log(s, AV_LOG_ERROR,
00220                "A non-rawvideo stream was selected, but yuv4mpeg only handles rawvideo streams\n");
00221         return AVERROR(EINVAL);
00222     }
00223 
00224     switch (s->streams[0]->codec->pix_fmt) {
00225     case PIX_FMT_YUV411P:
00226         av_log(s, AV_LOG_WARNING, "Warning: generating rarely used 4:1:1 YUV "
00227                "stream, some mjpegtools might not work.\n");
00228         break;
00229     case PIX_FMT_GRAY8:
00230     case PIX_FMT_GRAY16:
00231     case PIX_FMT_YUV420P:
00232     case PIX_FMT_YUV422P:
00233     case PIX_FMT_YUV444P:
00234         break;
00235     case PIX_FMT_YUV420P9:
00236     case PIX_FMT_YUV422P9:
00237     case PIX_FMT_YUV444P9:
00238     case PIX_FMT_YUV420P10:
00239     case PIX_FMT_YUV422P10:
00240     case PIX_FMT_YUV444P10:
00241     case PIX_FMT_YUV420P16:
00242     case PIX_FMT_YUV422P16:
00243     case PIX_FMT_YUV444P16:
00244         if (s->streams[0]->codec->strict_std_compliance >= FF_COMPLIANCE_NORMAL) {
00245             av_log(s, AV_LOG_ERROR, "'%s' is not a official yuv4mpegpipe pixel format. "
00246                    "Use '-strict -1' to encode to this pixel format.\n",
00247                    av_get_pix_fmt_name(s->streams[0]->codec->pix_fmt));
00248             return AVERROR(EINVAL);
00249         }
00250         av_log(s, AV_LOG_WARNING, "Warning: generating non standart YUV stream. "
00251                "Mjpegtools will not work.\n");
00252         break;
00253     default:
00254         av_log(s, AV_LOG_ERROR, "ERROR: yuv4mpeg can only handle "
00255                "yuv444p, yuv422p, yuv420p, yuv411p and gray8 pixel formats. "
00256                "And using 'strict -1' also yuv444p9, yuv422p9, yuv420p9, "
00257                "yuv444p10, yuv422p10, yuv420p10, "
00258                "yuv444p16, yuv422p16, yuv420p16 "
00259                "and gray16 pixel formats. "
00260                "Use -pix_fmt to select one.\n");
00261         return AVERROR(EIO);
00262     }
00263 
00264     *first_pkt = 1;
00265     return 0;
00266 }
00267 
00268 AVOutputFormat ff_yuv4mpegpipe_muxer = {
00269     .name              = "yuv4mpegpipe",
00270     .long_name         = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
00271     .extensions        = "y4m",
00272     .priv_data_size    = sizeof(int),
00273     .audio_codec       = AV_CODEC_ID_NONE,
00274     .video_codec       = AV_CODEC_ID_RAWVIDEO,
00275     .write_header      = yuv4_write_header,
00276     .write_packet      = yuv4_write_packet,
00277     .flags             = AVFMT_RAWPICTURE,
00278 };
00279 #endif
00280 
00281 /* Header size increased to allow room for optional flags */
00282 #define MAX_YUV4_HEADER 80
00283 #define MAX_FRAME_HEADER 80
00284 
00285 static int yuv4_read_header(AVFormatContext *s)
00286 {
00287     char header[MAX_YUV4_HEADER + 10];  // Include headroom for
00288                                         // the longest option
00289     char *tokstart, *tokend, *header_end;
00290     int i;
00291     AVIOContext *pb = s->pb;
00292     int width = -1, height  = -1, raten   = 0,
00293         rated =  0, aspectn =  0, aspectd = 0;
00294     enum PixelFormat pix_fmt = PIX_FMT_NONE, alt_pix_fmt = PIX_FMT_NONE;
00295     enum AVChromaLocation chroma_sample_location = AVCHROMA_LOC_UNSPECIFIED;
00296     AVStream *st;
00297     struct frame_attributes *s1 = s->priv_data;
00298 
00299     for (i = 0; i < MAX_YUV4_HEADER; i++) {
00300         header[i] = avio_r8(pb);
00301         if (header[i] == '\n') {
00302             header[i + 1] = 0x20;  // Add a space after last option.
00303                                    // Makes parsing "444" vs "444alpha" easier.
00304             header[i + 2] = 0;
00305             break;
00306         }
00307     }
00308     if (i == MAX_YUV4_HEADER)
00309         return -1;
00310     if (strncmp(header, Y4M_MAGIC, strlen(Y4M_MAGIC)))
00311         return -1;
00312 
00313     s1->interlaced_frame = 0;
00314     s1->top_field_first = 0;
00315     header_end = &header[i + 1]; // Include space
00316     for (tokstart = &header[strlen(Y4M_MAGIC) + 1];
00317          tokstart < header_end; tokstart++) {
00318         if (*tokstart == 0x20)
00319             continue;
00320         switch (*tokstart++) {
00321         case 'W': // Width. Required.
00322             width    = strtol(tokstart, &tokend, 10);
00323             tokstart = tokend;
00324             break;
00325         case 'H': // Height. Required.
00326             height   = strtol(tokstart, &tokend, 10);
00327             tokstart = tokend;
00328             break;
00329         case 'C': // Color space
00330             if (strncmp("420jpeg", tokstart, 7) == 0) {
00331                 pix_fmt = PIX_FMT_YUV420P;
00332                 chroma_sample_location = AVCHROMA_LOC_CENTER;
00333             } else if (strncmp("420mpeg2", tokstart, 8) == 0) {
00334                 pix_fmt = PIX_FMT_YUV420P;
00335                 chroma_sample_location = AVCHROMA_LOC_LEFT;
00336             } else if (strncmp("420paldv", tokstart, 8) == 0) {
00337                 pix_fmt = PIX_FMT_YUV420P;
00338                 chroma_sample_location = AVCHROMA_LOC_TOPLEFT;
00339             } else if (strncmp("420p16", tokstart, 6) == 0) {
00340                 pix_fmt = PIX_FMT_YUV420P16;
00341             } else if (strncmp("422p16", tokstart, 6) == 0) {
00342                 pix_fmt = PIX_FMT_YUV422P16;
00343             } else if (strncmp("444p16", tokstart, 6) == 0) {
00344                 pix_fmt = PIX_FMT_YUV444P16;
00345             } else if (strncmp("420p10", tokstart, 6) == 0) {
00346                 pix_fmt = PIX_FMT_YUV420P10;
00347             } else if (strncmp("422p10", tokstart, 6) == 0) {
00348                 pix_fmt = PIX_FMT_YUV422P10;
00349             } else if (strncmp("444p10", tokstart, 6) == 0) {
00350                 pix_fmt = PIX_FMT_YUV444P10;
00351             } else if (strncmp("420p9", tokstart, 5) == 0) {
00352                 pix_fmt = PIX_FMT_YUV420P9;
00353             } else if (strncmp("422p9", tokstart, 5) == 0) {
00354                 pix_fmt = PIX_FMT_YUV422P9;
00355             } else if (strncmp("444p9", tokstart, 5) == 0) {
00356                 pix_fmt = PIX_FMT_YUV444P9;
00357             } else if (strncmp("420", tokstart, 3) == 0) {
00358                 pix_fmt = PIX_FMT_YUV420P;
00359                 chroma_sample_location = AVCHROMA_LOC_CENTER;
00360             } else if (strncmp("411", tokstart, 3) == 0) {
00361                 pix_fmt = PIX_FMT_YUV411P;
00362             } else if (strncmp("422", tokstart, 3) == 0) {
00363                 pix_fmt = PIX_FMT_YUV422P;
00364             } else if (strncmp("444alpha", tokstart, 8) == 0 ) {
00365                 av_log(s, AV_LOG_ERROR, "Cannot handle 4:4:4:4 "
00366                        "YUV4MPEG stream.\n");
00367                 return -1;
00368             } else if (strncmp("444", tokstart, 3) == 0) {
00369                 pix_fmt = PIX_FMT_YUV444P;
00370             } else if (strncmp("mono16", tokstart, 6) == 0) {
00371                 pix_fmt = PIX_FMT_GRAY16;
00372             } else if (strncmp("mono", tokstart, 4) == 0) {
00373                 pix_fmt = PIX_FMT_GRAY8;
00374             } else {
00375                 av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains an unknown "
00376                        "pixel format.\n");
00377                 return -1;
00378             }
00379             while (tokstart < header_end && *tokstart != 0x20)
00380                 tokstart++;
00381             break;
00382         case 'I': // Interlace type
00383             switch (*tokstart++){
00384             case '?':
00385                 break;
00386             case 'p':
00387                 s1->interlaced_frame = 0;
00388                 break;
00389             case 't':
00390                 s1->interlaced_frame = 1;
00391                 s1->top_field_first = 1;
00392                 break;
00393             case 'b':
00394                 s1->interlaced_frame = 1;
00395                 s1->top_field_first = 0;
00396                 break;
00397             case 'm':
00398                 av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains mixed "
00399                        "interlaced and non-interlaced frames.\n");
00400                 return -1;
00401             default:
00402                 av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
00403                 return -1;
00404             }
00405             break;
00406         case 'F': // Frame rate
00407             sscanf(tokstart, "%d:%d", &raten, &rated); // 0:0 if unknown
00408             while (tokstart < header_end && *tokstart != 0x20)
00409                 tokstart++;
00410             break;
00411         case 'A': // Pixel aspect
00412             sscanf(tokstart, "%d:%d", &aspectn, &aspectd); // 0:0 if unknown
00413             while (tokstart < header_end && *tokstart != 0x20)
00414                 tokstart++;
00415             break;
00416         case 'X': // Vendor extensions
00417             if (strncmp("YSCSS=", tokstart, 6) == 0) {
00418                 // Older nonstandard pixel format representation
00419                 tokstart += 6;
00420                 if (strncmp("420JPEG", tokstart, 7) == 0)
00421                     alt_pix_fmt = PIX_FMT_YUV420P;
00422                 else if (strncmp("420MPEG2", tokstart, 8) == 0)
00423                     alt_pix_fmt = PIX_FMT_YUV420P;
00424                 else if (strncmp("420PALDV", tokstart, 8) == 0)
00425                     alt_pix_fmt = PIX_FMT_YUV420P;
00426                 else if (strncmp("420P9", tokstart, 5) == 0)
00427                     alt_pix_fmt = PIX_FMT_YUV420P9;
00428                 else if (strncmp("422P9", tokstart, 5) == 0)
00429                     alt_pix_fmt = PIX_FMT_YUV422P9;
00430                 else if (strncmp("444P9", tokstart, 5) == 0)
00431                     alt_pix_fmt = PIX_FMT_YUV444P9;
00432                 else if (strncmp("420P10", tokstart, 6) == 0)
00433                     alt_pix_fmt = PIX_FMT_YUV420P10;
00434                 else if (strncmp("422P10", tokstart, 6) == 0)
00435                     alt_pix_fmt = PIX_FMT_YUV422P10;
00436                 else if (strncmp("444P10", tokstart, 6) == 0)
00437                     alt_pix_fmt = PIX_FMT_YUV444P10;
00438                 else if (strncmp("420P16", tokstart, 6) == 0)
00439                     alt_pix_fmt = PIX_FMT_YUV420P16;
00440                 else if (strncmp("422P16", tokstart, 6) == 0)
00441                     alt_pix_fmt = PIX_FMT_YUV422P16;
00442                 else if (strncmp("444P16", tokstart, 6) == 0)
00443                     alt_pix_fmt = PIX_FMT_YUV444P16;
00444                 else if (strncmp("411", tokstart, 3) == 0)
00445                     alt_pix_fmt = PIX_FMT_YUV411P;
00446                 else if (strncmp("422", tokstart, 3) == 0)
00447                     alt_pix_fmt = PIX_FMT_YUV422P;
00448                 else if (strncmp("444", tokstart, 3) == 0)
00449                     alt_pix_fmt = PIX_FMT_YUV444P;
00450             }
00451             while (tokstart < header_end && *tokstart != 0x20)
00452                 tokstart++;
00453             break;
00454         }
00455     }
00456 
00457     if (width == -1 || height == -1) {
00458         av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
00459         return -1;
00460     }
00461 
00462     if (pix_fmt == PIX_FMT_NONE) {
00463         if (alt_pix_fmt == PIX_FMT_NONE)
00464             pix_fmt = PIX_FMT_YUV420P;
00465         else
00466             pix_fmt = alt_pix_fmt;
00467     }
00468 
00469     if (raten <= 0 || rated <= 0) {
00470         // Frame rate unknown
00471         raten = 25;
00472         rated = 1;
00473     }
00474 
00475     if (aspectn == 0 && aspectd == 0) {
00476         // Pixel aspect unknown
00477         aspectd = 1;
00478     }
00479 
00480     st = avformat_new_stream(s, NULL);
00481     if (!st)
00482         return AVERROR(ENOMEM);
00483     st->codec->width  = width;
00484     st->codec->height = height;
00485     av_reduce(&raten, &rated, raten, rated, (1UL << 31) - 1);
00486     avpriv_set_pts_info(st, 64, rated, raten);
00487     st->codec->pix_fmt                = pix_fmt;
00488     st->codec->codec_type             = AVMEDIA_TYPE_VIDEO;
00489     st->codec->codec_id               = AV_CODEC_ID_RAWVIDEO;
00490     st->sample_aspect_ratio           = (AVRational){ aspectn, aspectd };
00491     st->codec->chroma_sample_location = chroma_sample_location;
00492 
00493     return 0;
00494 }
00495 
00496 static int yuv4_read_packet(AVFormatContext *s, AVPacket *pkt)
00497 {
00498     int i;
00499     char header[MAX_FRAME_HEADER+1];
00500     int packet_size, width, height;
00501     AVStream *st = s->streams[0];
00502     struct frame_attributes *s1 = s->priv_data;
00503 
00504     for (i = 0; i < MAX_FRAME_HEADER; i++) {
00505         header[i] = avio_r8(s->pb);
00506         if (header[i] == '\n') {
00507             header[i + 1] = 0;
00508             break;
00509         }
00510     }
00511     if (i == MAX_FRAME_HEADER)
00512         return -1;
00513     if (strncmp(header, Y4M_FRAME_MAGIC, strlen(Y4M_FRAME_MAGIC)))
00514         return -1;
00515 
00516     width  = st->codec->width;
00517     height = st->codec->height;
00518 
00519     packet_size = avpicture_get_size(st->codec->pix_fmt, width, height);
00520     if (packet_size < 0)
00521         return -1;
00522 
00523     if (av_get_packet(s->pb, pkt, packet_size) != packet_size)
00524         return AVERROR(EIO);
00525 
00526     if (st->codec->coded_frame) {
00527         st->codec->coded_frame->interlaced_frame = s1->interlaced_frame;
00528         st->codec->coded_frame->top_field_first  = s1->top_field_first;
00529     }
00530 
00531     pkt->stream_index = 0;
00532     return 0;
00533 }
00534 
00535 static int yuv4_probe(AVProbeData *pd)
00536 {
00537     /* check file header */
00538     if (strncmp(pd->buf, Y4M_MAGIC, sizeof(Y4M_MAGIC) - 1) == 0)
00539         return AVPROBE_SCORE_MAX;
00540     else
00541         return 0;
00542 }
00543 
00544 #if CONFIG_YUV4MPEGPIPE_DEMUXER
00545 AVInputFormat ff_yuv4mpegpipe_demuxer = {
00546     .name           = "yuv4mpegpipe",
00547     .long_name      = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
00548     .priv_data_size = sizeof(struct frame_attributes),
00549     .read_probe     = yuv4_probe,
00550     .read_header    = yuv4_read_header,
00551     .read_packet    = yuv4_read_packet,
00552     .extensions     = "y4m",
00553 };
00554 #endif