libavformat/gxf.c

   1 /*
   2  * GXF demuxer.
   3  * Copyright (c) 2006 Reimar Doeffinger.
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21 #include "avformat.h"
  22 #include "common.h"
  23 #include "gxf.h"
  24
  25 typedef struct {
  26     int64_t first_field;
  27     int64_t last_field;
  28     AVRational frames_per_second;
  29     int32_t fields_per_frame;
  30 } st_info_t;
  31
  32 /**
  33  * \brief parses a packet header, extracting type and length
  34  * \param pb ByteIOContext to read header from
  35  * \param type detected packet type is stored here
  36  * \param length detected packet length, excluding header is stored here
  37  * \return 0 if header not found or contains invalid data, 1 otherwise
  38  */
  39 static int parse_packet_header(ByteIOContext *pb, pkt_type_t *type, int *length) {
  40     if (get_be32(pb))
  41         return 0;
  42     if (get_byte(pb) != 1)
  43         return 0;
  44     *type = get_byte(pb);
  45     *length = get_be32(pb);
  46     if ((*length >> 24) || *length < 16)
  47         return 0;
  48     *length -= 16;
  49     if (get_be32(pb))
  50         return 0;
  51     if (get_byte(pb) != 0xe1)
  52         return 0;
  53     if (get_byte(pb) != 0xe2)
  54         return 0;
  55     return 1;
  56 }
  57
  58 /**
  59  * \brief check if file starts with a PKT_MAP header
  60  */
  61 static int gxf_probe(AVProbeData *p) {
  62     static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
  63     static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
  64     if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
  65         !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
  66         return AVPROBE_SCORE_MAX;
  67     return 0;
  68 }
  69
  70 /**
  71  * \brief gets the stream index for the track with the specified id, creates new
  72  *        stream if not found
  73  * \param stream id of stream to find / add
  74  * \param format stream format identifier
  75  */
  76 static int get_sindex(AVFormatContext *s, int id, int format) {
  77     int i;
  78     AVStream *st = NULL;
  79     for (i = 0; i < s->nb_streams; i++) {
  80         if (s->streams[i]->id == id)
  81             return i;
  82     }
  83     st = av_new_stream(s, id);
  84     switch (format) {
  85         case 3:
  86         case 4:
  87             st->codec->codec_type = CODEC_TYPE_VIDEO;
  88             st->codec->codec_id = CODEC_ID_MJPEG;
  89             break;
  90         case 13:
  91         case 15:
  92             st->codec->codec_type = CODEC_TYPE_VIDEO;
  93             st->codec->codec_id = CODEC_ID_DVVIDEO;
  94             break;
  95         case 14:
  96         case 16:
  97             st->codec->codec_type = CODEC_TYPE_VIDEO;
  98             st->codec->codec_id = CODEC_ID_DVVIDEO;
  99             break;
 100         case 11:
 101         case 12:
 102         case 20:
 103             st->codec->codec_type = CODEC_TYPE_VIDEO;
 104             st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
 105             st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
 106             break;
 107         case 22:
 108         case 23:
 109             st->codec->codec_type = CODEC_TYPE_VIDEO;
 110             st->codec->codec_id = CODEC_ID_MPEG1VIDEO;
 111             st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
 112             break;
 113         case 9:
 114             st->codec->codec_type = CODEC_TYPE_AUDIO;
 115             st->codec->codec_id = CODEC_ID_PCM_S24LE;
 116             st->codec->channels = 1;
 117             st->codec->sample_rate = 48000;
 118             st->codec->bit_rate = 3 * 1 * 48000 * 8;
 119             st->codec->block_align = 3 * 1;
 120             st->codec->bits_per_sample = 24;
 121             break;
 122         case 10:
 123             st->codec->codec_type = CODEC_TYPE_AUDIO;
 124             st->codec->codec_id = CODEC_ID_PCM_S16LE;
 125             st->codec->channels = 1;
 126             st->codec->sample_rate = 48000;
 127             st->codec->bit_rate = 2 * 1 * 48000 * 8;
 128             st->codec->block_align = 2 * 1;
 129             st->codec->bits_per_sample = 16;
 130             break;
 131         case 17:
 132             st->codec->codec_type = CODEC_TYPE_AUDIO;
 133             st->codec->codec_id = CODEC_ID_AC3;
 134             st->codec->channels = 2;
 135             st->codec->sample_rate = 48000;
 136             break;
 137         // timecode tracks:
 138         case 7:
 139         case 8:
 140         case 24:
 141             st->codec->codec_type = CODEC_TYPE_DATA;
 142             st->codec->codec_id = CODEC_ID_NONE;
 143             break;
 144         default:
 145             st->codec->codec_type = CODEC_TYPE_UNKNOWN;
 146             st->codec->codec_id = CODEC_ID_NONE;
 147             break;
 148     }
 149     return s->nb_streams - 1;
 150 }
 151
 152 /**
 153  * \brief filters out interesting tags from material information.
 154  * \param len length of tag section, will be adjusted to contain remaining bytes
 155  * \param si struct to store collected information into
 156  */
 157 static void gxf_material_tags(ByteIOContext *pb, int *len, st_info_t *si) {
 158     si->first_field = AV_NOPTS_VALUE;
 159     si->last_field = AV_NOPTS_VALUE;
 160     while (*len >= 2) {
 161         mat_tag_t tag = get_byte(pb);
 162         int tlen = get_byte(pb);
 163         *len -= 2;
 164         if (tlen > *len)
 165             return;
 166         *len -= tlen;
 167         if (tlen == 4) {
 168             uint32_t value = get_be32(pb);
 169             if (tag == MAT_FIRST_FIELD)
 170                 si->first_field = value;
 171             else if (tag == MAT_LAST_FIELD)
 172                 si->last_field = value;
 173         } else
 174             url_fskip(pb, tlen);
 175     }
 176 }
 177
 178 /**
 179  * \brief convert fps tag value to AVRational fps
 180  * \param fps fps value from tag
 181  * \return fps as AVRational, or 0 / 0 if unknown
 182  */
 183 static AVRational fps_tag2avr(int32_t fps) {
 184     extern const AVRational ff_frame_rate_tab[];
 185     if (fps < 1 || fps > 9) fps = 9;
 186     return ff_frame_rate_tab[9 - fps]; // values have opposite order
 187 }
 188
 189 /**
 190  * \brief convert UMF attributes flags to AVRational fps
 191  * \param fps fps value from flags
 192  * \return fps as AVRational, or 0 / 0 if unknown
 193  */
 194 static AVRational fps_umf2avr(uint32_t flags) {
 195     static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
 196         {25, 1}, {30000, 1001}};
 197     int idx =  av_log2((flags & 0x7c0) >> 6);
 198     return map[idx];
 199 }
 200
 201 /**
 202  * \brief filters out interesting tags from track information.
 203  * \param len length of tag section, will be adjusted to contain remaining bytes
 204  * \param si struct to store collected information into
 205  */
 206 static void gxf_track_tags(ByteIOContext *pb, int *len, st_info_t *si) {
 207     si->frames_per_second = (AVRational){0, 0};
 208     si->fields_per_frame = 0;
 209     while (*len >= 2) {
 210         track_tag_t tag = get_byte(pb);
 211         int tlen = get_byte(pb);
 212         *len -= 2;
 213         if (tlen > *len)
 214             return;
 215         *len -= tlen;
 216         if (tlen == 4) {
 217             uint32_t value = get_be32(pb);
 218             if (tag == TRACK_FPS)
 219                 si->frames_per_second = fps_tag2avr(value);
 220             else if (tag == TRACK_FPF && (value == 1 || value == 2))
 221                 si->fields_per_frame = value;
 222         } else
 223             url_fskip(pb, tlen);
 224     }
 225 }
 226
 227 /**
 228  * \brief read index from FLT packet into stream 0 av_index
 229  */
 230 static void gxf_read_index(AVFormatContext *s, int pkt_len) {
 231     ByteIOContext *pb = s->pb;
 232     AVStream *st = s->streams[0];
 233     uint32_t fields_per_map = get_le32(pb);
 234     uint32_t map_cnt = get_le32(pb);
 235     int i;
 236     pkt_len -= 8;
 237     if (map_cnt > 1000) {
 238         av_log(s, AV_LOG_ERROR, "GXF: too many index entries %u (%x)\n", map_cnt, map_cnt);
 239         map_cnt = 1000;
 240     }
 241     if (pkt_len < 4 * map_cnt) {
 242         av_log(s, AV_LOG_ERROR, "GXF: invalid index length\n");
 243         url_fskip(pb, pkt_len);
 244         return;
 245     }
 246     pkt_len -= 4 * map_cnt;
 247     av_add_index_entry(st, 0, 0, 0, 0, 0);
 248     for (i = 0; i < map_cnt; i++)
 249         av_add_index_entry(st, (uint64_t)get_le32(pb) * 1024,
 250                            i * (uint64_t)fields_per_map + 1, 0, 0, 0);
 251     url_fskip(pb, pkt_len);
 252 }
 253
 254 static int gxf_header(AVFormatContext *s, AVFormatParameters *ap) {
 255     ByteIOContext *pb = s->pb;
 256     pkt_type_t pkt_type;
 257     int map_len;
 258     int len;
 259     AVRational main_timebase = {0, 0};
 260     st_info_t si;
 261     int i;
 262     if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
 263         av_log(s, AV_LOG_ERROR, "GXF: map packet not found\n");
 264         return 0;
 265     }
 266     map_len -= 2;
 267     if (get_byte(pb) != 0x0e0 || get_byte(pb) != 0xff) {
 268         av_log(s, AV_LOG_ERROR, "GXF: unknown version or invalid map preamble\n");
 269         return 0;
 270     }
 271     map_len -= 2;
 272     len = get_be16(pb); // length of material data section
 273     if (len > map_len) {
 274         av_log(s, AV_LOG_ERROR, "GXF: material data longer than map data\n");
 275         return 0;
 276     }
 277     map_len -= len;
 278     gxf_material_tags(pb, &len, &si);
 279     url_fskip(pb, len);
 280     map_len -= 2;
 281     len = get_be16(pb); // length of track description
 282     if (len > map_len) {
 283         av_log(s, AV_LOG_ERROR, "GXF: track description longer than map data\n");
 284         return 0;
 285     }
 286     map_len -= len;
 287     while (len > 0) {
 288         int track_type, track_id, track_len;
 289         AVStream *st;
 290         int idx;
 291         len -= 4;
 292         track_type = get_byte(pb);
 293         track_id = get_byte(pb);
 294         track_len = get_be16(pb);
 295         len -= track_len;
 296         gxf_track_tags(pb, &track_len, &si);
 297         url_fskip(pb, track_len);
 298         if (!(track_type & 0x80)) {
 299            av_log(s, AV_LOG_ERROR, "GXF: invalid track type %x\n", track_type);
 300            continue;
 301         }
 302         track_type &= 0x7f;
 303         if ((track_id & 0xc0) != 0xc0) {
 304            av_log(s, AV_LOG_ERROR, "GXF: invalid track id %x\n", track_id);
 305            continue;
 306         }
 307         track_id &= 0x3f;
 308         idx = get_sindex(s, track_id, track_type);
 309         if (idx < 0) continue;
 310         st = s->streams[idx];
 311         if (!main_timebase.num || !main_timebase.den) {
 312             main_timebase.num = si.frames_per_second.den;
 313             main_timebase.den = si.frames_per_second.num * si.fields_per_frame;
 314         }
 315         st->start_time = si.first_field;
 316         if (si.first_field != AV_NOPTS_VALUE && si.last_field != AV_NOPTS_VALUE)
 317             st->duration = si.last_field - si.first_field;
 318     }
 319     if (len < 0)
 320         av_log(s, AV_LOG_ERROR, "GXF: invalid track description length specified\n");
 321     if (map_len)
 322         url_fskip(pb, map_len);
 323     if (!parse_packet_header(pb, &pkt_type, &len)) {
 324         av_log(s, AV_LOG_ERROR, "GXF: sync lost in header\n");
 325         return -1;
 326     }
 327     if (pkt_type == PKT_FLT) {
 328         gxf_read_index(s, len);
 329         if (!parse_packet_header(pb, &pkt_type, &len)) {
 330             av_log(s, AV_LOG_ERROR, "GXF: sync lost in header\n");
 331             return -1;
 332         }
 333     }
 334     if (pkt_type == PKT_UMF) {
 335         if (len >= 0x39) {
 336             AVRational fps;
 337             len -= 0x39;
 338             url_fskip(pb, 5); // preamble
 339             url_fskip(pb, 0x30); // payload description
 340             fps = fps_umf2avr(get_le32(pb));
 341             if (!main_timebase.num || !main_timebase.den) {
 342                 // this may not always be correct, but simply the best we can get
 343                 main_timebase.num = fps.den;
 344                 main_timebase.den = fps.num;
 345             }
 346         } else
 347             av_log(s, AV_LOG_INFO, "GXF: UMF packet too short\n");
 348     } else
 349         av_log(s, AV_LOG_INFO, "GXF: UMF packet missing\n");
 350     url_fskip(pb, len);
 351     if (!main_timebase.num || !main_timebase.den)
 352         main_timebase = (AVRational){1, 50}; // set some arbitrary fallback
 353     for (i = 0; i < s->nb_streams; i++) {
 354         AVStream *st = s->streams[i];
 355         av_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
 356     }
 357     return 0;
 358 }
 359
 360 #define READ_ONE() \
 361     { \
 362         if (!max_interval-- || url_feof(pb)) \
 363             goto out; \
 364         tmp = tmp << 8 | get_byte(pb); \
 365     }
 366
 367 /**
 368  * \brief resync the stream on the next media packet with specified properties
 369  * \param max_interval how many bytes to search for matching packet at most
 370  * \param track track id the media packet must belong to, -1 for any
 371  * \param timestamp minimum timestamp (== field number) the packet must have, -1 for any
 372  * \return timestamp of packet found
 373  */
 374 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
 375     uint32_t tmp;
 376     uint64_t last_pos;
 377     uint64_t last_found_pos = 0;
 378     int cur_track;
 379     int64_t cur_timestamp = AV_NOPTS_VALUE;
 380     int len;
 381     ByteIOContext *pb = s->pb;
 382     pkt_type_t type;
 383     tmp = get_be32(pb);
 384 start:
 385     while (tmp)
 386         READ_ONE();
 387     READ_ONE();
 388     if (tmp != 1)
 389         goto start;
 390     last_pos = url_ftell(pb);
 391     url_fseek(pb, -5, SEEK_CUR);
 392     if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
 393         url_fseek(pb, last_pos, SEEK_SET);
 394         goto start;
 395     }
 396     get_byte(pb);
 397     cur_track = get_byte(pb);
 398     cur_timestamp = get_be32(pb);
 399     last_found_pos = url_ftell(pb) - 16 - 6;
 400     if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
 401         url_fseek(pb, last_pos, SEEK_SET);
 402         goto start;
 403     }
 404 out:
 405     if (last_found_pos)
 406         url_fseek(pb, last_found_pos, SEEK_SET);
 407     return cur_timestamp;
 408 }
 409
 410 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
 411     ByteIOContext *pb = s->pb;
 412     pkt_type_t pkt_type;
 413     int pkt_len;
 414     while (!url_feof(pb)) {
 415         int track_type, track_id, ret;
 416         int field_nr;
 417         if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
 418             if (!url_feof(pb))
 419                 av_log(s, AV_LOG_ERROR, "GXF: sync lost\n");
 420             return -1;
 421         }
 422         if (pkt_type == PKT_FLT) {
 423             gxf_read_index(s, pkt_len);
 424             continue;
 425         }
 426         if (pkt_type != PKT_MEDIA) {
 427             url_fskip(pb, pkt_len);
 428             continue;
 429         }
 430         if (pkt_len < 16) {
 431             av_log(s, AV_LOG_ERROR, "GXF: invalid media packet length\n");
 432             continue;
 433         }
 434         pkt_len -= 16;
 435         track_type = get_byte(pb);
 436         track_id = get_byte(pb);
 437         field_nr = get_be32(pb);
 438         get_be32(pb); // field information
 439         get_be32(pb); // "timeline" field number
 440         get_byte(pb); // flags
 441         get_byte(pb); // reserved
 442         // NOTE: there is also data length information in the
 443         // field information, it might be better to take this into account
 444         // as well.
 445         ret = av_get_packet(pb, pkt, pkt_len);
 446         pkt->stream_index = get_sindex(s, track_id, track_type);
 447         pkt->dts = field_nr;
 448         return ret;
 449     }
 450     return AVERROR(EIO);
 451 }
 452
 453 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
 454     uint64_t pos;
 455     uint64_t maxlen = 100 * 1024 * 1024;
 456     AVStream *st = s->streams[0];
 457     int64_t start_time = s->streams[stream_index]->start_time;
 458     int64_t found;
 459     int idx;
 460     if (timestamp < start_time) timestamp = start_time;
 461     idx = av_index_search_timestamp(st, timestamp - start_time,
 462                                     AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
 463     if (idx < 0)
 464         return -1;
 465     pos = st->index_entries[idx].pos;
 466     if (idx < st->nb_index_entries - 2)
 467         maxlen = st->index_entries[idx + 2].pos - pos;
 468     maxlen = FFMAX(maxlen, 200 * 1024);
 469     url_fseek(s->pb, pos, SEEK_SET);
 470     found = gxf_resync_media(s, maxlen, -1, timestamp);
 471     if (FFABS(found - timestamp) > 4)
 472         return -1;
 473     return 0;
 474 }
 475
 476 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
 477                                   int64_t *pos, int64_t pos_limit) {
 478     ByteIOContext *pb = s->pb;
 479     int64_t res;
 480     url_fseek(pb, *pos, SEEK_SET);
 481     res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
 482     *pos = url_ftell(pb);
 483     return res;
 484 }
 485
 486 AVInputFormat gxf_demuxer = {
 487     "gxf",
 488     "GXF format",
 489     0,
 490     gxf_probe,
 491     gxf_header,
 492     gxf_packet,
 493     NULL,
 494     gxf_seek,
 495     gxf_read_timestamp,
 496 };