aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/ipmovie.c
blob: 731b0396bc7a31e8dd91efe3a7a29f7d4b382df1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
/*
 * Interplay MVE File Demuxer
 * Copyright (c) 2003 The ffmpeg Project
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file ipmovie.c
 * Interplay MVE file demuxer
 * by Mike Melanson (melanson@pcisys.net)
 * For more information regarding the Interplay MVE file format, visit:
 *   http://www.pcisys.net/~melanson/codecs/
 * The aforementioned site also contains a command line utility for parsing
 * IP MVE files so that you can get a good idea of the typical structure of
 * such files. This demuxer is not the best example to use if you are trying
 * to write your own as it uses a rather roundabout approach for splitting
 * up and sending out the chunks.
 */

#include "avformat.h"

/* debugging support: #define DEBUG_IPMOVIE as non-zero to see extremely
 * verbose information about the demux process */
#define DEBUG_IPMOVIE 0

#if DEBUG_IPMOVIE
#define debug_ipmovie printf
#else
static inline void debug_ipmovie(const char *format, ...) { }
#endif

#define IPMOVIE_SIGNATURE "Interplay MVE File\x1A\0"
#define IPMOVIE_SIGNATURE_SIZE 20
#define CHUNK_PREAMBLE_SIZE 4
#define OPCODE_PREAMBLE_SIZE 4

#define CHUNK_INIT_AUDIO   0x0000
#define CHUNK_AUDIO_ONLY   0x0001
#define CHUNK_INIT_VIDEO   0x0002
#define CHUNK_VIDEO        0x0003
#define CHUNK_SHUTDOWN     0x0004
#define CHUNK_END          0x0005
/* these last types are used internally */
#define CHUNK_DONE         0xFFFC
#define CHUNK_NOMEM        0xFFFD
#define CHUNK_EOF          0xFFFE
#define CHUNK_BAD          0xFFFF

#define OPCODE_END_OF_STREAM           0x00
#define OPCODE_END_OF_CHUNK            0x01
#define OPCODE_CREATE_TIMER            0x02
#define OPCODE_INIT_AUDIO_BUFFERS      0x03
#define OPCODE_START_STOP_AUDIO        0x04
#define OPCODE_INIT_VIDEO_BUFFERS      0x05
#define OPCODE_UNKNOWN_06              0x06
#define OPCODE_SEND_BUFFER             0x07
#define OPCODE_AUDIO_FRAME             0x08
#define OPCODE_SILENCE_FRAME           0x09
#define OPCODE_INIT_VIDEO_MODE         0x0A
#define OPCODE_CREATE_GRADIENT         0x0B
#define OPCODE_SET_PALETTE             0x0C
#define OPCODE_SET_PALETTE_COMPRESSED  0x0D
#define OPCODE_UNKNOWN_0E              0x0E
#define OPCODE_SET_DECODING_MAP        0x0F
#define OPCODE_UNKNOWN_10              0x10
#define OPCODE_VIDEO_DATA              0x11
#define OPCODE_UNKNOWN_12              0x12
#define OPCODE_UNKNOWN_13              0x13
#define OPCODE_UNKNOWN_14              0x14
#define OPCODE_UNKNOWN_15              0x15

#define PALETTE_COUNT 256

typedef struct IPMVEContext {

    unsigned char *buf;
    int buf_size;

    float fps;
    int frame_pts_inc;

    unsigned int video_width;
    unsigned int video_height;
    int64_t video_pts;

    unsigned int audio_bits;
    unsigned int audio_channels;
    unsigned int audio_sample_rate;
    unsigned int audio_type;
    unsigned int audio_frame_count;

    int video_stream_index;
    int audio_stream_index;

    offset_t audio_chunk_offset;
    int audio_chunk_size;
    offset_t video_chunk_offset;
    int video_chunk_size;
    offset_t decode_map_chunk_offset;
    int decode_map_chunk_size;

    offset_t next_chunk_offset;

    AVPaletteControl palette_control;

} IPMVEContext;

static int load_ipmovie_packet(IPMVEContext *s, ByteIOContext *pb,
    AVPacket *pkt) {

    int chunk_type;
    int64_t audio_pts = 0;

    if (s->audio_chunk_offset) {

        /* adjust for PCM audio by skipping chunk header */
        if (s->audio_type != CODEC_ID_INTERPLAY_DPCM) {
            s->audio_chunk_offset += 6;
            s->audio_chunk_size -= 6;
        }

        url_fseek(pb, s->audio_chunk_offset, SEEK_SET);
        s->audio_chunk_offset = 0;

        /* figure out the audio pts */
        audio_pts = 90000;
        audio_pts *= s->audio_frame_count;
        audio_pts /= s->audio_sample_rate;

        if (s->audio_chunk_size != av_get_packet(pb, pkt, s->audio_chunk_size))
            return CHUNK_EOF;

        pkt->stream_index = s->audio_stream_index;
        pkt->pts = audio_pts;

        /* audio frame maintenance */
        if (s->audio_type != CODEC_ID_INTERPLAY_DPCM)
            s->audio_frame_count +=
            (s->audio_chunk_size / s->audio_channels / (s->audio_bits / 8));
        else
            s->audio_frame_count +=
                (s->audio_chunk_size - 6) / s->audio_channels;

        debug_ipmovie("sending audio frame with pts %lld (%d audio frames)\n",
            audio_pts, s->audio_frame_count);

        chunk_type = CHUNK_VIDEO;

    } else if (s->decode_map_chunk_offset) {

        /* send both the decode map and the video data together */

        if (av_new_packet(pkt, s->decode_map_chunk_size + s->video_chunk_size))
            return CHUNK_NOMEM;

        pkt->pos= s->decode_map_chunk_offset;
        url_fseek(pb, s->decode_map_chunk_offset, SEEK_SET);
        s->decode_map_chunk_offset = 0;

        if (get_buffer(pb, pkt->data, s->decode_map_chunk_size) !=
            s->decode_map_chunk_size) {
            av_free_packet(pkt);
            return CHUNK_EOF;
        }

        url_fseek(pb, s->video_chunk_offset, SEEK_SET);
        s->video_chunk_offset = 0;

        if (get_buffer(pb, pkt->data + s->decode_map_chunk_size,
            s->video_chunk_size) != s->video_chunk_size) {
            av_free_packet(pkt);
            return CHUNK_EOF;
        }

        pkt->stream_index = s->video_stream_index;
        pkt->pts = s->video_pts;

        debug_ipmovie("sending video frame with pts %lld\n",
            pkt->pts);

        s->video_pts += s->frame_pts_inc;

        chunk_type = CHUNK_VIDEO;

    } else {

        url_fseek(pb, s->next_chunk_offset, SEEK_SET);
        chunk_type = CHUNK_DONE;

    }

    return chunk_type;
}

/* This function loads and processes a single chunk in an IP movie file.
 * It returns the type of chunk that was processed. */
static int process_ipmovie_chunk(IPMVEContext *s, ByteIOContext *pb,
    AVPacket *pkt)
{
    unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
    int chunk_type;
    int chunk_size;
    unsigned char opcode_preamble[OPCODE_PREAMBLE_SIZE];
    unsigned char opcode_type;
    unsigned char opcode_version;
    int opcode_size;
    unsigned char scratch[1024];
    int i, j;
    int first_color, last_color;
    int audio_flags;
    unsigned char r, g, b;

    /* see if there are any pending packets */
    chunk_type = load_ipmovie_packet(s, pb, pkt);
    if ((chunk_type == CHUNK_VIDEO) && (chunk_type != CHUNK_DONE))
        return chunk_type;

    /* read the next chunk, wherever the file happens to be pointing */
    if (url_feof(pb))
        return CHUNK_EOF;
    if (get_buffer(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
        CHUNK_PREAMBLE_SIZE)
        return CHUNK_BAD;
    chunk_size = LE_16(&chunk_preamble[0]);
    chunk_type = LE_16(&chunk_preamble[2]);

    debug_ipmovie("chunk type 0x%04X, 0x%04X bytes: ", chunk_type, chunk_size);

    switch (chunk_type) {

    case CHUNK_INIT_AUDIO:
        debug_ipmovie("initialize audio\n");
        break;

    case CHUNK_AUDIO_ONLY:
        debug_ipmovie("audio only\n");
        break;

    case CHUNK_INIT_VIDEO:
        debug_ipmovie("initialize video\n");
        break;

    case CHUNK_VIDEO:
        debug_ipmovie("video (and audio)\n");
        break;

    case CHUNK_SHUTDOWN:
        debug_ipmovie("shutdown\n");
        break;

    case CHUNK_END:
        debug_ipmovie("end\n");
        break;

    default:
        debug_ipmovie("invalid chunk\n");
        chunk_type = CHUNK_BAD;
        break;

    }

    while ((chunk_size > 0) && (chunk_type != CHUNK_BAD)) {

        /* read the next chunk, wherever the file happens to be pointing */
       if (url_feof(pb)) {
            chunk_type = CHUNK_EOF;
            break;
        }
        if (get_buffer(pb, opcode_preamble, CHUNK_PREAMBLE_SIZE) !=
            CHUNK_PREAMBLE_SIZE) {
            chunk_type = CHUNK_BAD;
            break;
        }

        opcode_size = LE_16(&opcode_preamble[0]);
        opcode_type = opcode_preamble[2];
        opcode_version = opcode_preamble[3];

        chunk_size -= OPCODE_PREAMBLE_SIZE;
        chunk_size -= opcode_size;
        if (chunk_size < 0) {
            debug_ipmovie("chunk_size countdown just went negative\n");
            chunk_type = CHUNK_BAD;
            break;
        }

        debug_ipmovie("  opcode type %02X, version %d, 0x%04X bytes: ",
            opcode_type, opcode_version, opcode_size);
        switch (opcode_type) {

        case OPCODE_END_OF_STREAM:
            debug_ipmovie("end of stream\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_END_OF_CHUNK:
            debug_ipmovie("end of chunk\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_CREATE_TIMER:
            debug_ipmovie("create timer\n");
            if ((opcode_version > 0) || (opcode_size > 6)) {
                debug_ipmovie("bad create_timer opcode\n");
                chunk_type = CHUNK_BAD;
                break;
            }
            if (get_buffer(pb, scratch, opcode_size) !=
                opcode_size) {
                chunk_type = CHUNK_BAD;
                break;
            }
            s->fps = 1000000.0 / (LE_32(&scratch[0]) * LE_16(&scratch[4]));
            s->frame_pts_inc = 90000 / s->fps;
            debug_ipmovie("  %.2f frames/second (timer div = %d, subdiv = %d)\n",
                s->fps, LE_32(&scratch[0]), LE_16(&scratch[4]));
            break;

        case OPCODE_INIT_AUDIO_BUFFERS:
            debug_ipmovie("initialize audio buffers\n");
            if ((opcode_version > 1) || (opcode_size > 10)) {
                debug_ipmovie("bad init_audio_buffers opcode\n");
                chunk_type = CHUNK_BAD;
                break;
            }
            if (get_buffer(pb, scratch, opcode_size) !=
                opcode_size) {
                chunk_type = CHUNK_BAD;
                break;
            }
            s->audio_sample_rate = LE_16(&scratch[4]);
            audio_flags = LE_16(&scratch[2]);
            /* bit 0 of the flags: 0 = mono, 1 = stereo */
            s->audio_channels = (audio_flags & 1) + 1;
            /* bit 1 of the flags: 0 = 8 bit, 1 = 16 bit */
            s->audio_bits = (((audio_flags >> 1) & 1) + 1) * 8;
            /* bit 2 indicates compressed audio in version 1 opcode */
            if ((opcode_version == 1) && (audio_flags & 0x4))
                s->audio_type = CODEC_ID_INTERPLAY_DPCM;
            else if (s->audio_bits == 16)
                s->audio_type = CODEC_ID_PCM_S16LE;
            else
                s->audio_type = CODEC_ID_PCM_U8;
            debug_ipmovie("audio: %d bits, %d Hz, %s, %s format\n",
                s->audio_bits,
                s->audio_sample_rate,
                (s->audio_channels == 2) ? "stereo" : "mono",
                (s->audio_type == CODEC_ID_INTERPLAY_DPCM) ?
                "Interplay audio" : "PCM");
            break;

        case OPCODE_START_STOP_AUDIO:
            debug_ipmovie("start/stop audio\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_INIT_VIDEO_BUFFERS:
            debug_ipmovie("initialize video buffers\n");
            if ((opcode_version > 2) || (opcode_size > 8)) {
                debug_ipmovie("bad init_video_buffers opcode\n");
                chunk_type = CHUNK_BAD;
                break;
            }
            if (get_buffer(pb, scratch, opcode_size) !=
                opcode_size) {
                chunk_type = CHUNK_BAD;
                break;
            }
            s->video_width = LE_16(&scratch[0]) * 8;
            s->video_height = LE_16(&scratch[2]) * 8;
            debug_ipmovie("video resolution: %d x %d\n",
                s->video_width, s->video_height);
            break;

        case OPCODE_UNKNOWN_06:
        case OPCODE_UNKNOWN_0E:
        case OPCODE_UNKNOWN_10:
        case OPCODE_UNKNOWN_12:
        case OPCODE_UNKNOWN_13:
        case OPCODE_UNKNOWN_14:
        case OPCODE_UNKNOWN_15:
            debug_ipmovie("unknown (but documented) opcode %02X\n", opcode_type);
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_SEND_BUFFER:
            debug_ipmovie("send buffer\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_AUDIO_FRAME:
            debug_ipmovie("audio frame\n");

            /* log position and move on for now */
            s->audio_chunk_offset = url_ftell(pb);
            s->audio_chunk_size = opcode_size;
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_SILENCE_FRAME:
            debug_ipmovie("silence frame\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_INIT_VIDEO_MODE:
            debug_ipmovie("initialize video mode\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_CREATE_GRADIENT:
            debug_ipmovie("create gradient\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_SET_PALETTE:
            debug_ipmovie("set palette\n");
            /* check for the logical maximum palette size
             * (3 * 256 + 4 bytes) */
            if (opcode_size > 0x304) {
                debug_ipmovie("demux_ipmovie: set_palette opcode too large\n");
                chunk_type = CHUNK_BAD;
                break;
            }
            if (get_buffer(pb, scratch, opcode_size) != opcode_size) {
                chunk_type = CHUNK_BAD;
                break;
            }

            /* load the palette into internal data structure */
            first_color = LE_16(&scratch[0]);
            last_color = first_color + LE_16(&scratch[2]) - 1;
            /* sanity check (since they are 16 bit values) */
            if ((first_color > 0xFF) || (last_color > 0xFF)) {
                debug_ipmovie("demux_ipmovie: set_palette indices out of range (%d -> %d)\n",
                    first_color, last_color);
                chunk_type = CHUNK_BAD;
                break;
            }
            j = 4;  /* offset of first palette data */
            for (i = first_color; i <= last_color; i++) {
                /* the palette is stored as a 6-bit VGA palette, thus each
                 * component is shifted up to a 8-bit range */
                r = scratch[j++] * 4;
                g = scratch[j++] * 4;
                b = scratch[j++] * 4;
                s->palette_control.palette[i] = (r << 16) | (g << 8) | (b);
            }
            /* indicate a palette change */
            s->palette_control.palette_changed = 1;
            break;

        case OPCODE_SET_PALETTE_COMPRESSED:
            debug_ipmovie("set palette compressed\n");
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_SET_DECODING_MAP:
            debug_ipmovie("set decoding map\n");

            /* log position and move on for now */
            s->decode_map_chunk_offset = url_ftell(pb);
            s->decode_map_chunk_size = opcode_size;
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        case OPCODE_VIDEO_DATA:
            debug_ipmovie("set video data\n");

            /* log position and move on for now */
            s->video_chunk_offset = url_ftell(pb);
            s->video_chunk_size = opcode_size;
            url_fseek(pb, opcode_size, SEEK_CUR);
            break;

        default:
            debug_ipmovie("*** unknown opcode type\n");
            chunk_type = CHUNK_BAD;
            break;

        }
    }

    /* make a note of where the stream is sitting */
    s->next_chunk_offset = url_ftell(pb);

    /* dispatch the first of any pending packets */
    if ((chunk_type == CHUNK_VIDEO) || (chunk_type == CHUNK_AUDIO_ONLY))
        chunk_type = load_ipmovie_packet(s, pb, pkt);

    return chunk_type;
}

static int ipmovie_probe(AVProbeData *p)
{
    if (p->buf_size < IPMOVIE_SIGNATURE_SIZE)
        return 0;
    if (strncmp(p->buf, IPMOVIE_SIGNATURE, IPMOVIE_SIGNATURE_SIZE) != 0)
        return 0;

    return AVPROBE_SCORE_MAX;
}

static int ipmovie_read_header(AVFormatContext *s,
                               AVFormatParameters *ap)
{
    IPMVEContext *ipmovie = (IPMVEContext *)s->priv_data;
    ByteIOContext *pb = &s->pb;
    AVPacket pkt;
    AVStream *st;
    unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
    int chunk_type;

    /* initialize private context members */
    ipmovie->video_pts = ipmovie->audio_frame_count = 0;
    ipmovie->audio_chunk_offset = ipmovie->video_chunk_offset =
    ipmovie->decode_map_chunk_offset = 0;

    /* on the first read, this will position the stream at the first chunk */
    ipmovie->next_chunk_offset = IPMOVIE_SIGNATURE_SIZE + 6;

    /* process the first chunk which should be CHUNK_INIT_VIDEO */
    if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_VIDEO)
        return AVERROR_INVALIDDATA;

    /* peek ahead to the next chunk-- if it is an init audio chunk, process
     * it; if it is the first video chunk, this is a silent file */
    if (get_buffer(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
        CHUNK_PREAMBLE_SIZE)
        return AVERROR_IO;
    chunk_type = LE_16(&chunk_preamble[2]);
    url_fseek(pb, -CHUNK_PREAMBLE_SIZE, SEEK_CUR);

    if (chunk_type == CHUNK_VIDEO)
        ipmovie->audio_type = 0;  /* no audio */
    else if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_AUDIO)
        return AVERROR_INVALIDDATA;

    /* initialize the stream decoders */
    st = av_new_stream(s, 0);
    if (!st)
        return AVERROR_NOMEM;
    av_set_pts_info(st, 33, 1, 90000);
    ipmovie->video_stream_index = st->index;
    st->codec->codec_type = CODEC_TYPE_VIDEO;
    st->codec->codec_id = CODEC_ID_INTERPLAY_VIDEO;
    st->codec->codec_tag = 0;  /* no fourcc */
    st->codec->width = ipmovie->video_width;
    st->codec->height = ipmovie->video_height;

    /* palette considerations */
    st->codec->palctrl = &ipmovie->palette_control;

    if (ipmovie->audio_type) {
        st = av_new_stream(s, 0);
        if (!st)
            return AVERROR_NOMEM;
        av_set_pts_info(st, 33, 1, 90000);
        ipmovie->audio_stream_index = st->index;
        st->codec->codec_type = CODEC_TYPE_AUDIO;
        st->codec->codec_id = ipmovie->audio_type;
        st->codec->codec_tag = 0;  /* no tag */
        st->codec->channels = ipmovie->audio_channels;
        st->codec->sample_rate = ipmovie->audio_sample_rate;
        st->codec->bits_per_sample = ipmovie->audio_bits;
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
            st->codec->bits_per_sample;
        if (st->codec->codec_id == CODEC_ID_INTERPLAY_DPCM)
            st->codec->bit_rate /= 2;
        st->codec->block_align = st->codec->channels * st->codec->bits_per_sample;
    }

    return 0;
}

static int ipmovie_read_packet(AVFormatContext *s,
                               AVPacket *pkt)
{
    IPMVEContext *ipmovie = (IPMVEContext *)s->priv_data;
    ByteIOContext *pb = &s->pb;
    int ret;

    ret = process_ipmovie_chunk(ipmovie, pb, pkt);
    if (ret == CHUNK_BAD)
        ret = AVERROR_INVALIDDATA;
    else if (ret == CHUNK_EOF)
        ret = AVERROR_IO;
    else if (ret == CHUNK_NOMEM)
        ret = AVERROR_NOMEM;
    else
        ret = 0;

    return ret;
}

static int ipmovie_read_close(AVFormatContext *s)
{
//    IPMVEContext *ipmovie = (IPMVEContext *)s->priv_data;

    return 0;
}

static AVInputFormat ipmovie_iformat = {
    "ipmovie",
    "Interplay MVE format",
    sizeof(IPMVEContext),
    ipmovie_probe,
    ipmovie_read_header,
    ipmovie_read_packet,
    ipmovie_read_close,
};

int ipmovie_init(void)
{
    av_register_input_format(&ipmovie_iformat);
    return 0;
}