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ffmpeg / libavformat / gxf.c @ 3abe5fbd

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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.
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 *
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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
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
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 *
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 * 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
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21
#include "avformat.h"
22
#include "common.h"
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#include "gxf.h"
24

    
25
typedef struct {
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    int64_t first_field;
27
    int64_t last_field;
28
    AVRational frames_per_second;
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    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.
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            break;
107
        case 22:
108
        case 23:
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            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;
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            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;
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            st->codec->bit_rate = 2 * 1 * 48000 * 8;
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            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
};