Statistics
| Branch: | Revision:

ffmpeg / libavformat / gxf.c @ 72415b2a

History | View | Annotate | Download (16.8 KB)

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

    
22
#include "libavutil/common.h"
23
#include "avformat.h"
24
#include "gxf.h"
25

    
26
struct gxf_stream_info {
27
    int64_t first_field;
28
    int64_t last_field;
29
    AVRational frames_per_second;
30
    int32_t fields_per_frame;
31
};
32

    
33
/**
34
 * \brief parses a packet header, extracting type and length
35
 * \param pb ByteIOContext to read header from
36
 * \param type detected packet type is stored here
37
 * \param length detected packet length, excluding header is stored here
38
 * \return 0 if header not found or contains invalid data, 1 otherwise
39
 */
40
static int parse_packet_header(ByteIOContext *pb, GXFPktType *type, int *length) {
41
    if (get_be32(pb))
42
        return 0;
43
    if (get_byte(pb) != 1)
44
        return 0;
45
    *type = get_byte(pb);
46
    *length = get_be32(pb);
47
    if ((*length >> 24) || *length < 16)
48
        return 0;
49
    *length -= 16;
50
    if (get_be32(pb))
51
        return 0;
52
    if (get_byte(pb) != 0xe1)
53
        return 0;
54
    if (get_byte(pb) != 0xe2)
55
        return 0;
56
    return 1;
57
}
58

    
59
/**
60
 * \brief check if file starts with a PKT_MAP header
61
 */
62
static int gxf_probe(AVProbeData *p) {
63
    static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
64
    static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
65
    if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
66
        !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
67
        return AVPROBE_SCORE_MAX;
68
    return 0;
69
}
70

    
71
/**
72
 * \brief gets the stream index for the track with the specified id, creates new
73
 *        stream if not found
74
 * \param stream id of stream to find / add
75
 * \param format stream format identifier
76
 */
77
static int get_sindex(AVFormatContext *s, int id, int format) {
78
    int i;
79
    AVStream *st = NULL;
80
    for (i = 0; i < s->nb_streams; i++) {
81
        if (s->streams[i]->id == id)
82
            return i;
83
    }
84
    st = av_new_stream(s, id);
85
    if (!st)
86
        return AVERROR(ENOMEM);
87
    switch (format) {
88
        case 3:
89
        case 4:
90
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
91
            st->codec->codec_id = CODEC_ID_MJPEG;
92
            break;
93
        case 13:
94
        case 15:
95
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
96
            st->codec->codec_id = CODEC_ID_DVVIDEO;
97
            break;
98
        case 14:
99
        case 16:
100
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
101
            st->codec->codec_id = CODEC_ID_DVVIDEO;
102
            break;
103
        case 11:
104
        case 12:
105
        case 20:
106
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
107
            st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
108
            st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
109
            break;
110
        case 22:
111
        case 23:
112
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
113
            st->codec->codec_id = CODEC_ID_MPEG1VIDEO;
114
            st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
115
            break;
116
        case 9:
117
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
118
            st->codec->codec_id = CODEC_ID_PCM_S24LE;
119
            st->codec->channels = 1;
120
            st->codec->sample_rate = 48000;
121
            st->codec->bit_rate = 3 * 1 * 48000 * 8;
122
            st->codec->block_align = 3 * 1;
123
            st->codec->bits_per_coded_sample = 24;
124
            break;
125
        case 10:
126
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
127
            st->codec->codec_id = CODEC_ID_PCM_S16LE;
128
            st->codec->channels = 1;
129
            st->codec->sample_rate = 48000;
130
            st->codec->bit_rate = 2 * 1 * 48000 * 8;
131
            st->codec->block_align = 2 * 1;
132
            st->codec->bits_per_coded_sample = 16;
133
            break;
134
        case 17:
135
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
136
            st->codec->codec_id = CODEC_ID_AC3;
137
            st->codec->channels = 2;
138
            st->codec->sample_rate = 48000;
139
            break;
140
        // timecode tracks:
141
        case 7:
142
        case 8:
143
        case 24:
144
            st->codec->codec_type = AVMEDIA_TYPE_DATA;
145
            st->codec->codec_id = CODEC_ID_NONE;
146
            break;
147
        default:
148
            st->codec->codec_type = AVMEDIA_TYPE_UNKNOWN;
149
            st->codec->codec_id = CODEC_ID_NONE;
150
            break;
151
    }
152
    return s->nb_streams - 1;
153
}
154

    
155
/**
156
 * \brief filters out interesting tags from material information.
157
 * \param len length of tag section, will be adjusted to contain remaining bytes
158
 * \param si struct to store collected information into
159
 */
160
static void gxf_material_tags(ByteIOContext *pb, int *len, struct gxf_stream_info *si) {
161
    si->first_field = AV_NOPTS_VALUE;
162
    si->last_field = AV_NOPTS_VALUE;
163
    while (*len >= 2) {
164
        GXFMatTag tag = get_byte(pb);
165
        int tlen = get_byte(pb);
166
        *len -= 2;
167
        if (tlen > *len)
168
            return;
169
        *len -= tlen;
170
        if (tlen == 4) {
171
            uint32_t value = get_be32(pb);
172
            if (tag == MAT_FIRST_FIELD)
173
                si->first_field = value;
174
            else if (tag == MAT_LAST_FIELD)
175
                si->last_field = value;
176
        } else
177
            url_fskip(pb, tlen);
178
    }
179
}
180

    
181
/**
182
 * \brief convert fps tag value to AVRational fps
183
 * \param fps fps value from tag
184
 * \return fps as AVRational, or 0 / 0 if unknown
185
 */
186
static AVRational fps_tag2avr(int32_t fps) {
187
    extern const AVRational ff_frame_rate_tab[];
188
    if (fps < 1 || fps > 9) fps = 9;
189
    return ff_frame_rate_tab[9 - fps]; // values have opposite order
190
}
191

    
192
/**
193
 * \brief convert UMF attributes flags to AVRational fps
194
 * \param fps fps value from flags
195
 * \return fps as AVRational, or 0 / 0 if unknown
196
 */
197
static AVRational fps_umf2avr(uint32_t flags) {
198
    static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
199
        {25, 1}, {30000, 1001}};
200
    int idx =  av_log2((flags & 0x7c0) >> 6);
201
    return map[idx];
202
}
203

    
204
/**
205
 * \brief filters out interesting tags from track information.
206
 * \param len length of tag section, will be adjusted to contain remaining bytes
207
 * \param si struct to store collected information into
208
 */
209
static void gxf_track_tags(ByteIOContext *pb, int *len, struct gxf_stream_info *si) {
210
    si->frames_per_second = (AVRational){0, 0};
211
    si->fields_per_frame = 0;
212
    while (*len >= 2) {
213
        GXFTrackTag tag = get_byte(pb);
214
        int tlen = get_byte(pb);
215
        *len -= 2;
216
        if (tlen > *len)
217
            return;
218
        *len -= tlen;
219
        if (tlen == 4) {
220
            uint32_t value = get_be32(pb);
221
            if (tag == TRACK_FPS)
222
                si->frames_per_second = fps_tag2avr(value);
223
            else if (tag == TRACK_FPF && (value == 1 || value == 2))
224
                si->fields_per_frame = value;
225
        } else
226
            url_fskip(pb, tlen);
227
    }
228
}
229

    
230
/**
231
 * \brief read index from FLT packet into stream 0 av_index
232
 */
233
static void gxf_read_index(AVFormatContext *s, int pkt_len) {
234
    ByteIOContext *pb = s->pb;
235
    AVStream *st = s->streams[0];
236
    uint32_t fields_per_map = get_le32(pb);
237
    uint32_t map_cnt = get_le32(pb);
238
    int i;
239
    pkt_len -= 8;
240
    if (map_cnt > 1000) {
241
        av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);
242
        map_cnt = 1000;
243
    }
244
    if (pkt_len < 4 * map_cnt) {
245
        av_log(s, AV_LOG_ERROR, "invalid index length\n");
246
        url_fskip(pb, pkt_len);
247
        return;
248
    }
249
    pkt_len -= 4 * map_cnt;
250
    av_add_index_entry(st, 0, 0, 0, 0, 0);
251
    for (i = 0; i < map_cnt; i++)
252
        av_add_index_entry(st, (uint64_t)get_le32(pb) * 1024,
253
                           i * (uint64_t)fields_per_map + 1, 0, 0, 0);
254
    url_fskip(pb, pkt_len);
255
}
256

    
257
static int gxf_header(AVFormatContext *s, AVFormatParameters *ap) {
258
    ByteIOContext *pb = s->pb;
259
    GXFPktType pkt_type;
260
    int map_len;
261
    int len;
262
    AVRational main_timebase = {0, 0};
263
    struct gxf_stream_info si;
264
    int i;
265
    if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
266
        av_log(s, AV_LOG_ERROR, "map packet not found\n");
267
        return 0;
268
    }
269
    map_len -= 2;
270
    if (get_byte(pb) != 0x0e0 || get_byte(pb) != 0xff) {
271
        av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
272
        return 0;
273
    }
274
    map_len -= 2;
275
    len = get_be16(pb); // length of material data section
276
    if (len > map_len) {
277
        av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
278
        return 0;
279
    }
280
    map_len -= len;
281
    gxf_material_tags(pb, &len, &si);
282
    url_fskip(pb, len);
283
    map_len -= 2;
284
    len = get_be16(pb); // length of track description
285
    if (len > map_len) {
286
        av_log(s, AV_LOG_ERROR, "track description longer than map data\n");
287
        return 0;
288
    }
289
    map_len -= len;
290
    while (len > 0) {
291
        int track_type, track_id, track_len;
292
        AVStream *st;
293
        int idx;
294
        len -= 4;
295
        track_type = get_byte(pb);
296
        track_id = get_byte(pb);
297
        track_len = get_be16(pb);
298
        len -= track_len;
299
        gxf_track_tags(pb, &track_len, &si);
300
        url_fskip(pb, track_len);
301
        if (!(track_type & 0x80)) {
302
           av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
303
           continue;
304
        }
305
        track_type &= 0x7f;
306
        if ((track_id & 0xc0) != 0xc0) {
307
           av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);
308
           continue;
309
        }
310
        track_id &= 0x3f;
311
        idx = get_sindex(s, track_id, track_type);
312
        if (idx < 0) continue;
313
        st = s->streams[idx];
314
        if (!main_timebase.num || !main_timebase.den) {
315
            main_timebase.num = si.frames_per_second.den;
316
            main_timebase.den = si.frames_per_second.num * 2;
317
        }
318
        st->start_time = si.first_field;
319
        if (si.first_field != AV_NOPTS_VALUE && si.last_field != AV_NOPTS_VALUE)
320
            st->duration = si.last_field - si.first_field;
321
    }
322
    if (len < 0)
323
        av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");
324
    if (map_len)
325
        url_fskip(pb, map_len);
326
    if (!parse_packet_header(pb, &pkt_type, &len)) {
327
        av_log(s, AV_LOG_ERROR, "sync lost in header\n");
328
        return -1;
329
    }
330
    if (pkt_type == PKT_FLT) {
331
        gxf_read_index(s, len);
332
        if (!parse_packet_header(pb, &pkt_type, &len)) {
333
            av_log(s, AV_LOG_ERROR, "sync lost in header\n");
334
            return -1;
335
        }
336
    }
337
    if (pkt_type == PKT_UMF) {
338
        if (len >= 0x39) {
339
            AVRational fps;
340
            len -= 0x39;
341
            url_fskip(pb, 5); // preamble
342
            url_fskip(pb, 0x30); // payload description
343
            fps = fps_umf2avr(get_le32(pb));
344
            if (!main_timebase.num || !main_timebase.den) {
345
                // this may not always be correct, but simply the best we can get
346
                main_timebase.num = fps.den;
347
                main_timebase.den = fps.num * 2;
348
            }
349
        } else
350
            av_log(s, AV_LOG_INFO, "UMF packet too short\n");
351
    } else
352
        av_log(s, AV_LOG_INFO, "UMF packet missing\n");
353
    url_fskip(pb, len);
354
    // set a fallback value, 60000/1001 is specified for audio-only files
355
    // so use that regardless of why we do not know the video frame rate.
356
    if (!main_timebase.num || !main_timebase.den)
357
        main_timebase = (AVRational){1001, 60000};
358
    for (i = 0; i < s->nb_streams; i++) {
359
        AVStream *st = s->streams[i];
360
        av_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
361
    }
362
    return 0;
363
}
364

    
365
#define READ_ONE() \
366
    { \
367
        if (!max_interval-- || url_feof(pb)) \
368
            goto out; \
369
        tmp = tmp << 8 | get_byte(pb); \
370
    }
371

    
372
/**
373
 * \brief resync the stream on the next media packet with specified properties
374
 * \param max_interval how many bytes to search for matching packet at most
375
 * \param track track id the media packet must belong to, -1 for any
376
 * \param timestamp minimum timestamp (== field number) the packet must have, -1 for any
377
 * \return timestamp of packet found
378
 */
379
static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
380
    uint32_t tmp;
381
    uint64_t last_pos;
382
    uint64_t last_found_pos = 0;
383
    int cur_track;
384
    int64_t cur_timestamp = AV_NOPTS_VALUE;
385
    int len;
386
    ByteIOContext *pb = s->pb;
387
    GXFPktType type;
388
    tmp = get_be32(pb);
389
start:
390
    while (tmp)
391
        READ_ONE();
392
    READ_ONE();
393
    if (tmp != 1)
394
        goto start;
395
    last_pos = url_ftell(pb);
396
    url_fseek(pb, -5, SEEK_CUR);
397
    if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
398
        url_fseek(pb, last_pos, SEEK_SET);
399
        goto start;
400
    }
401
    get_byte(pb);
402
    cur_track = get_byte(pb);
403
    cur_timestamp = get_be32(pb);
404
    last_found_pos = url_ftell(pb) - 16 - 6;
405
    if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
406
        url_fseek(pb, last_pos, SEEK_SET);
407
        goto start;
408
    }
409
out:
410
    if (last_found_pos)
411
        url_fseek(pb, last_found_pos, SEEK_SET);
412
    return cur_timestamp;
413
}
414

    
415
static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
416
    ByteIOContext *pb = s->pb;
417
    GXFPktType pkt_type;
418
    int pkt_len;
419
    while (!url_feof(pb)) {
420
        AVStream *st;
421
        int track_type, track_id, ret;
422
        int field_nr, field_info, skip = 0;
423
        int stream_index;
424
        if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
425
            if (!url_feof(pb))
426
                av_log(s, AV_LOG_ERROR, "sync lost\n");
427
            return -1;
428
        }
429
        if (pkt_type == PKT_FLT) {
430
            gxf_read_index(s, pkt_len);
431
            continue;
432
        }
433
        if (pkt_type != PKT_MEDIA) {
434
            url_fskip(pb, pkt_len);
435
            continue;
436
        }
437
        if (pkt_len < 16) {
438
            av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
439
            continue;
440
        }
441
        pkt_len -= 16;
442
        track_type = get_byte(pb);
443
        track_id = get_byte(pb);
444
        stream_index = get_sindex(s, track_id, track_type);
445
        if (stream_index < 0)
446
            return stream_index;
447
        st = s->streams[stream_index];
448
        field_nr = get_be32(pb);
449
        field_info = get_be32(pb);
450
        get_be32(pb); // "timeline" field number
451
        get_byte(pb); // flags
452
        get_byte(pb); // reserved
453
        if (st->codec->codec_id == CODEC_ID_PCM_S24LE ||
454
            st->codec->codec_id == CODEC_ID_PCM_S16LE) {
455
            int first = field_info >> 16;
456
            int last  = field_info & 0xffff; // last is exclusive
457
            int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
458
            if (first <= last && last*bps <= pkt_len) {
459
                url_fskip(pb, first*bps);
460
                skip = pkt_len - last*bps;
461
                pkt_len = (last-first)*bps;
462
            } else
463
                av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
464
        }
465
        ret = av_get_packet(pb, pkt, pkt_len);
466
        if (skip)
467
            url_fskip(pb, skip);
468
        pkt->stream_index = stream_index;
469
        pkt->dts = field_nr;
470
        return ret;
471
    }
472
    return AVERROR(EIO);
473
}
474

    
475
static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
476
    uint64_t pos;
477
    uint64_t maxlen = 100 * 1024 * 1024;
478
    AVStream *st = s->streams[0];
479
    int64_t start_time = s->streams[stream_index]->start_time;
480
    int64_t found;
481
    int idx;
482
    if (timestamp < start_time) timestamp = start_time;
483
    idx = av_index_search_timestamp(st, timestamp - start_time,
484
                                    AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
485
    if (idx < 0)
486
        return -1;
487
    pos = st->index_entries[idx].pos;
488
    if (idx < st->nb_index_entries - 2)
489
        maxlen = st->index_entries[idx + 2].pos - pos;
490
    maxlen = FFMAX(maxlen, 200 * 1024);
491
    url_fseek(s->pb, pos, SEEK_SET);
492
    found = gxf_resync_media(s, maxlen, -1, timestamp);
493
    if (FFABS(found - timestamp) > 4)
494
        return -1;
495
    return 0;
496
}
497

    
498
static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
499
                                  int64_t *pos, int64_t pos_limit) {
500
    ByteIOContext *pb = s->pb;
501
    int64_t res;
502
    url_fseek(pb, *pos, SEEK_SET);
503
    res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
504
    *pos = url_ftell(pb);
505
    return res;
506
}
507

    
508
AVInputFormat gxf_demuxer = {
509
    "gxf",
510
    NULL_IF_CONFIG_SMALL("GXF format"),
511
    0,
512
    gxf_probe,
513
    gxf_header,
514
    gxf_packet,
515
    NULL,
516
    gxf_seek,
517
    gxf_read_timestamp,
518
};