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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
 *
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 * 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
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 * 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 "internal.h"
25
#include "gxf.h"
26

    
27
struct gxf_stream_info {
28
    int64_t first_field;
29
    int64_t last_field;
30
    AVRational frames_per_second;
31
    int32_t fields_per_frame;
32
};
33

    
34
/**
35
 * \brief parses a packet header, extracting type and length
36
 * \param pb AVIOContext to read header from
37
 * \param type detected packet type is stored here
38
 * \param length detected packet length, excluding header is stored here
39
 * \return 0 if header not found or contains invalid data, 1 otherwise
40
 */
41
static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {
42
    if (avio_rb32(pb))
43
        return 0;
44
    if (avio_r8(pb) != 1)
45
        return 0;
46
    *type = avio_r8(pb);
47
    *length = avio_rb32(pb);
48
    if ((*length >> 24) || *length < 16)
49
        return 0;
50
    *length -= 16;
51
    if (avio_rb32(pb))
52
        return 0;
53
    if (avio_r8(pb) != 0xe1)
54
        return 0;
55
    if (avio_r8(pb) != 0xe2)
56
        return 0;
57
    return 1;
58
}
59

    
60
/**
61
 * \brief check if file starts with a PKT_MAP header
62
 */
63
static int gxf_probe(AVProbeData *p) {
64
    static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
65
    static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
66
    if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
67
        !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
68
        return AVPROBE_SCORE_MAX;
69
    return 0;
70
}
71

    
72
/**
73
 * \brief gets the stream index for the track with the specified id, creates new
74
 *        stream if not found
75
 * \param id     id of stream to find / add
76
 * \param format stream format identifier
77
 */
78
static int get_sindex(AVFormatContext *s, int id, int format) {
79
    int i;
80
    AVStream *st = NULL;
81
    i = ff_find_stream_index(s, id);
82
    if (i >= 0)
83
        return i;
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(AVIOContext *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 = avio_r8(pb);
165
        int tlen = avio_r8(pb);
166
        *len -= 2;
167
        if (tlen > *len)
168
            return;
169
        *len -= tlen;
170
        if (tlen == 4) {
171
            uint32_t value = avio_rb32(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 flags UMF flags to convert
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(AVIOContext *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 = avio_r8(pb);
214
        int tlen = avio_r8(pb);
215
        *len -= 2;
216
        if (tlen > *len)
217
            return;
218
        *len -= tlen;
219
        if (tlen == 4) {
220
            uint32_t value = avio_rb32(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
    AVIOContext *pb = s->pb;
235
    AVStream *st = s->streams[0];
236
    uint32_t fields_per_map = avio_rl32(pb);
237
    uint32_t map_cnt = avio_rl32(pb);
238
    int i;
239
    pkt_len -= 8;
240
    if (s->flags & AVFMT_FLAG_IGNIDX) {
241
        url_fskip(pb, pkt_len);
242
        return;
243
    }
244
    if (map_cnt > 1000) {
245
        av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);
246
        map_cnt = 1000;
247
    }
248
    if (pkt_len < 4 * map_cnt) {
249
        av_log(s, AV_LOG_ERROR, "invalid index length\n");
250
        url_fskip(pb, pkt_len);
251
        return;
252
    }
253
    pkt_len -= 4 * map_cnt;
254
    av_add_index_entry(st, 0, 0, 0, 0, 0);
255
    for (i = 0; i < map_cnt; i++)
256
        av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,
257
                           i * (uint64_t)fields_per_map + 1, 0, 0, 0);
258
    url_fskip(pb, pkt_len);
259
}
260

    
261
static int gxf_header(AVFormatContext *s, AVFormatParameters *ap) {
262
    AVIOContext *pb = s->pb;
263
    GXFPktType pkt_type;
264
    int map_len;
265
    int len;
266
    AVRational main_timebase = {0, 0};
267
    struct gxf_stream_info si;
268
    int i;
269
    if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
270
        av_log(s, AV_LOG_ERROR, "map packet not found\n");
271
        return 0;
272
    }
273
    map_len -= 2;
274
    if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {
275
        av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
276
        return 0;
277
    }
278
    map_len -= 2;
279
    len = avio_rb16(pb); // length of material data section
280
    if (len > map_len) {
281
        av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
282
        return 0;
283
    }
284
    map_len -= len;
285
    gxf_material_tags(pb, &len, &si);
286
    url_fskip(pb, len);
287
    map_len -= 2;
288
    len = avio_rb16(pb); // length of track description
289
    if (len > map_len) {
290
        av_log(s, AV_LOG_ERROR, "track description longer than map data\n");
291
        return 0;
292
    }
293
    map_len -= len;
294
    while (len > 0) {
295
        int track_type, track_id, track_len;
296
        AVStream *st;
297
        int idx;
298
        len -= 4;
299
        track_type = avio_r8(pb);
300
        track_id = avio_r8(pb);
301
        track_len = avio_rb16(pb);
302
        len -= track_len;
303
        gxf_track_tags(pb, &track_len, &si);
304
        url_fskip(pb, track_len);
305
        if (!(track_type & 0x80)) {
306
           av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
307
           continue;
308
        }
309
        track_type &= 0x7f;
310
        if ((track_id & 0xc0) != 0xc0) {
311
           av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);
312
           continue;
313
        }
314
        track_id &= 0x3f;
315
        idx = get_sindex(s, track_id, track_type);
316
        if (idx < 0) continue;
317
        st = s->streams[idx];
318
        if (!main_timebase.num || !main_timebase.den) {
319
            main_timebase.num = si.frames_per_second.den;
320
            main_timebase.den = si.frames_per_second.num * 2;
321
        }
322
        st->start_time = si.first_field;
323
        if (si.first_field != AV_NOPTS_VALUE && si.last_field != AV_NOPTS_VALUE)
324
            st->duration = si.last_field - si.first_field;
325
    }
326
    if (len < 0)
327
        av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");
328
    if (map_len)
329
        url_fskip(pb, map_len);
330
    if (!parse_packet_header(pb, &pkt_type, &len)) {
331
        av_log(s, AV_LOG_ERROR, "sync lost in header\n");
332
        return -1;
333
    }
334
    if (pkt_type == PKT_FLT) {
335
        gxf_read_index(s, len);
336
        if (!parse_packet_header(pb, &pkt_type, &len)) {
337
            av_log(s, AV_LOG_ERROR, "sync lost in header\n");
338
            return -1;
339
        }
340
    }
341
    if (pkt_type == PKT_UMF) {
342
        if (len >= 0x39) {
343
            AVRational fps;
344
            len -= 0x39;
345
            url_fskip(pb, 5); // preamble
346
            url_fskip(pb, 0x30); // payload description
347
            fps = fps_umf2avr(avio_rl32(pb));
348
            if (!main_timebase.num || !main_timebase.den) {
349
                // this may not always be correct, but simply the best we can get
350
                main_timebase.num = fps.den;
351
                main_timebase.den = fps.num * 2;
352
            }
353
        } else
354
            av_log(s, AV_LOG_INFO, "UMF packet too short\n");
355
    } else
356
        av_log(s, AV_LOG_INFO, "UMF packet missing\n");
357
    url_fskip(pb, len);
358
    // set a fallback value, 60000/1001 is specified for audio-only files
359
    // so use that regardless of why we do not know the video frame rate.
360
    if (!main_timebase.num || !main_timebase.den)
361
        main_timebase = (AVRational){1001, 60000};
362
    for (i = 0; i < s->nb_streams; i++) {
363
        AVStream *st = s->streams[i];
364
        av_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
365
    }
366
    return 0;
367
}
368

    
369
#define READ_ONE() \
370
    { \
371
        if (!max_interval-- || url_feof(pb)) \
372
            goto out; \
373
        tmp = tmp << 8 | avio_r8(pb); \
374
    }
375

    
376
/**
377
 * \brief resync the stream on the next media packet with specified properties
378
 * \param max_interval how many bytes to search for matching packet at most
379
 * \param track track id the media packet must belong to, -1 for any
380
 * \param timestamp minimum timestamp (== field number) the packet must have, -1 for any
381
 * \return timestamp of packet found
382
 */
383
static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
384
    uint32_t tmp;
385
    uint64_t last_pos;
386
    uint64_t last_found_pos = 0;
387
    int cur_track;
388
    int64_t cur_timestamp = AV_NOPTS_VALUE;
389
    int len;
390
    AVIOContext *pb = s->pb;
391
    GXFPktType type;
392
    tmp = avio_rb32(pb);
393
start:
394
    while (tmp)
395
        READ_ONE();
396
    READ_ONE();
397
    if (tmp != 1)
398
        goto start;
399
    last_pos = url_ftell(pb);
400
    if (url_fseek(pb, -5, SEEK_CUR) < 0)
401
        goto out;
402
    if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
403
        if (url_fseek(pb, last_pos, SEEK_SET) < 0)
404
            goto out;
405
        goto start;
406
    }
407
    avio_r8(pb);
408
    cur_track = avio_r8(pb);
409
    cur_timestamp = avio_rb32(pb);
410
    last_found_pos = url_ftell(pb) - 16 - 6;
411
    if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
412
        if (url_fseek(pb, last_pos, SEEK_SET) >= 0)
413
            goto start;
414
    }
415
out:
416
    if (last_found_pos)
417
        url_fseek(pb, last_found_pos, SEEK_SET);
418
    return cur_timestamp;
419
}
420

    
421
static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
422
    AVIOContext *pb = s->pb;
423
    GXFPktType pkt_type;
424
    int pkt_len;
425
    while (!url_feof(pb)) {
426
        AVStream *st;
427
        int track_type, track_id, ret;
428
        int field_nr, field_info, skip = 0;
429
        int stream_index;
430
        if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
431
            if (!url_feof(pb))
432
                av_log(s, AV_LOG_ERROR, "sync lost\n");
433
            return -1;
434
        }
435
        if (pkt_type == PKT_FLT) {
436
            gxf_read_index(s, pkt_len);
437
            continue;
438
        }
439
        if (pkt_type != PKT_MEDIA) {
440
            url_fskip(pb, pkt_len);
441
            continue;
442
        }
443
        if (pkt_len < 16) {
444
            av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
445
            continue;
446
        }
447
        pkt_len -= 16;
448
        track_type = avio_r8(pb);
449
        track_id = avio_r8(pb);
450
        stream_index = get_sindex(s, track_id, track_type);
451
        if (stream_index < 0)
452
            return stream_index;
453
        st = s->streams[stream_index];
454
        field_nr = avio_rb32(pb);
455
        field_info = avio_rb32(pb);
456
        avio_rb32(pb); // "timeline" field number
457
        avio_r8(pb); // flags
458
        avio_r8(pb); // reserved
459
        if (st->codec->codec_id == CODEC_ID_PCM_S24LE ||
460
            st->codec->codec_id == CODEC_ID_PCM_S16LE) {
461
            int first = field_info >> 16;
462
            int last  = field_info & 0xffff; // last is exclusive
463
            int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
464
            if (first <= last && last*bps <= pkt_len) {
465
                url_fskip(pb, first*bps);
466
                skip = pkt_len - last*bps;
467
                pkt_len = (last-first)*bps;
468
            } else
469
                av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
470
        }
471
        ret = av_get_packet(pb, pkt, pkt_len);
472
        if (skip)
473
            url_fskip(pb, skip);
474
        pkt->stream_index = stream_index;
475
        pkt->dts = field_nr;
476
        return ret;
477
    }
478
    return AVERROR(EIO);
479
}
480

    
481
static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
482
    int res = 0;
483
    uint64_t pos;
484
    uint64_t maxlen = 100 * 1024 * 1024;
485
    AVStream *st = s->streams[0];
486
    int64_t start_time = s->streams[stream_index]->start_time;
487
    int64_t found;
488
    int idx;
489
    if (timestamp < start_time) timestamp = start_time;
490
    idx = av_index_search_timestamp(st, timestamp - start_time,
491
                                    AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
492
    if (idx < 0)
493
        return -1;
494
    pos = st->index_entries[idx].pos;
495
    if (idx < st->nb_index_entries - 2)
496
        maxlen = st->index_entries[idx + 2].pos - pos;
497
    maxlen = FFMAX(maxlen, 200 * 1024);
498
    res = url_fseek(s->pb, pos, SEEK_SET);
499
    if (res < 0)
500
        return res;
501
    found = gxf_resync_media(s, maxlen, -1, timestamp);
502
    if (FFABS(found - timestamp) > 4)
503
        return -1;
504
    return 0;
505
}
506

    
507
static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
508
                                  int64_t *pos, int64_t pos_limit) {
509
    AVIOContext *pb = s->pb;
510
    int64_t res;
511
    if (url_fseek(pb, *pos, SEEK_SET) < 0)
512
        return AV_NOPTS_VALUE;
513
    res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
514
    *pos = url_ftell(pb);
515
    return res;
516
}
517

    
518
AVInputFormat ff_gxf_demuxer = {
519
    "gxf",
520
    NULL_IF_CONFIG_SMALL("GXF format"),
521
    0,
522
    gxf_probe,
523
    gxf_header,
524
    gxf_packet,
525
    NULL,
526
    gxf_seek,
527
    gxf_read_timestamp,
528
};