path: root/libavformat/ipmovie.c (plain)
blob: a83909f14835e5b1c2f47e71c54fbbe41558f7c8

1	/*
2	* Interplay MVE File Demuxer
3	* Copyright (c) 2003 The FFmpeg project
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	/**
23	* @file
24	* Interplay MVE file demuxer
25	* by Mike Melanson (melanson@pcisys.net)
26	* For more information regarding the Interplay MVE file format, visit:
27	* http://www.pcisys.net/~melanson/codecs/
28	* The aforementioned site also contains a command line utility for parsing
29	* IP MVE files so that you can get a good idea of the typical structure of
30	* such files. This demuxer is not the best example to use if you are trying
31	* to write your own as it uses a rather roundabout approach for splitting
32	* up and sending out the chunks.
33	*/
34
35	#include "libavutil/channel_layout.h"
36	#include "libavutil/intreadwrite.h"
37	#include "avformat.h"
38	#include "internal.h"
39
40	#define CHUNK_PREAMBLE_SIZE 4
41	#define OPCODE_PREAMBLE_SIZE 4
42
43	#define CHUNK_INIT_AUDIO 0x0000
44	#define CHUNK_AUDIO_ONLY 0x0001
45	#define CHUNK_INIT_VIDEO 0x0002
46	#define CHUNK_VIDEO 0x0003
47	#define CHUNK_SHUTDOWN 0x0004
48	#define CHUNK_END 0x0005
49	/* these last types are used internally */
50	#define CHUNK_DONE 0xFFFC
51	#define CHUNK_NOMEM 0xFFFD
52	#define CHUNK_EOF 0xFFFE
53	#define CHUNK_BAD 0xFFFF
54
55	#define OPCODE_END_OF_STREAM 0x00
56	#define OPCODE_END_OF_CHUNK 0x01
57	#define OPCODE_CREATE_TIMER 0x02
58	#define OPCODE_INIT_AUDIO_BUFFERS 0x03
59	#define OPCODE_START_STOP_AUDIO 0x04
60	#define OPCODE_INIT_VIDEO_BUFFERS 0x05
61	#define OPCODE_UNKNOWN_06 0x06
62	#define OPCODE_SEND_BUFFER 0x07
63	#define OPCODE_AUDIO_FRAME 0x08
64	#define OPCODE_SILENCE_FRAME 0x09
65	#define OPCODE_INIT_VIDEO_MODE 0x0A
66	#define OPCODE_CREATE_GRADIENT 0x0B
67	#define OPCODE_SET_PALETTE 0x0C
68	#define OPCODE_SET_PALETTE_COMPRESSED 0x0D
69	#define OPCODE_UNKNOWN_0E 0x0E
70	#define OPCODE_SET_DECODING_MAP 0x0F
71	#define OPCODE_UNKNOWN_10 0x10
72	#define OPCODE_VIDEO_DATA 0x11
73	#define OPCODE_UNKNOWN_12 0x12
74	#define OPCODE_UNKNOWN_13 0x13
75	#define OPCODE_UNKNOWN_14 0x14
76	#define OPCODE_UNKNOWN_15 0x15
77
78	#define PALETTE_COUNT 256
79
80	typedef struct IPMVEContext {
81	AVFormatContext *avf;
82	unsigned char *buf;
83	int buf_size;
84
85	uint64_t frame_pts_inc;
86
87	unsigned int video_bpp;
88	unsigned int video_width;
89	unsigned int video_height;
90	int64_t video_pts;
91	uint32_t palette[256];
92	int has_palette;
93	int changed;
94
95	unsigned int audio_bits;
96	unsigned int audio_channels;
97	unsigned int audio_sample_rate;
98	enum AVCodecID audio_type;
99	unsigned int audio_frame_count;
100
101	int video_stream_index;
102	int audio_stream_index;
103
104	int64_t audio_chunk_offset;
105	int audio_chunk_size;
106	int64_t video_chunk_offset;
107	int video_chunk_size;
108	int64_t decode_map_chunk_offset;
109	int decode_map_chunk_size;
110
111	int64_t next_chunk_offset;
112
113	} IPMVEContext;
114
115	static int load_ipmovie_packet(IPMVEContext *s, AVIOContext *pb,
116	AVPacket *pkt) {
117
118	int chunk_type;
119
120	if (s->audio_chunk_offset && s->audio_channels && s->audio_bits) {
121	if (s->audio_type == AV_CODEC_ID_NONE) {
122	av_log(s->avf, AV_LOG_ERROR, "Can not read audio packet before"
123	"audio codec is known\n");
124	return CHUNK_BAD;
125	}
126
127	/* adjust for PCM audio by skipping chunk header */
128	if (s->audio_type != AV_CODEC_ID_INTERPLAY_DPCM) {
129	s->audio_chunk_offset += 6;
130	s->audio_chunk_size -= 6;
131	}
132
133	avio_seek(pb, s->audio_chunk_offset, SEEK_SET);
134	s->audio_chunk_offset = 0;
135
136	if (s->audio_chunk_size != av_get_packet(pb, pkt, s->audio_chunk_size))
137	return CHUNK_EOF;
138
139	pkt->stream_index = s->audio_stream_index;
140	pkt->pts = s->audio_frame_count;
141
142	/* audio frame maintenance */
143	if (s->audio_type != AV_CODEC_ID_INTERPLAY_DPCM)
144	s->audio_frame_count +=
145	(s->audio_chunk_size / s->audio_channels / (s->audio_bits / 8));
146	else
147	s->audio_frame_count +=
148	(s->audio_chunk_size - 6 - s->audio_channels) / s->audio_channels;
149
150	av_log(s->avf, AV_LOG_TRACE, "sending audio frame with pts %"PRId64" (%d audio frames)\n",
151	pkt->pts, s->audio_frame_count);
152
153	chunk_type = CHUNK_VIDEO;
154
155	} else if (s->decode_map_chunk_offset) {
156
157	/* send both the decode map and the video data together */
158
159	if (av_new_packet(pkt, 2 + s->decode_map_chunk_size + s->video_chunk_size))
160	return CHUNK_NOMEM;
161
162	if (s->has_palette) {
163	uint8_t *pal;
164
165	pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
166	AVPALETTE_SIZE);
167	if (pal) {
168	memcpy(pal, s->palette, AVPALETTE_SIZE);
169	s->has_palette = 0;
170	}
171	}
172
173	if (s->changed) {
174	ff_add_param_change(pkt, 0, 0, 0, s->video_width, s->video_height);
175	s->changed = 0;
176	}
177	pkt->pos= s->decode_map_chunk_offset;
178	avio_seek(pb, s->decode_map_chunk_offset, SEEK_SET);
179	s->decode_map_chunk_offset = 0;
180
181	AV_WL16(pkt->data, s->decode_map_chunk_size);
182	if (avio_read(pb, pkt->data + 2, s->decode_map_chunk_size) !=
183	s->decode_map_chunk_size) {
184	av_packet_unref(pkt);
185	return CHUNK_EOF;
186	}
187
188	avio_seek(pb, s->video_chunk_offset, SEEK_SET);
189	s->video_chunk_offset = 0;
190
191	if (avio_read(pb, pkt->data + 2 + s->decode_map_chunk_size,
192	s->video_chunk_size) != s->video_chunk_size) {
193	av_packet_unref(pkt);
194	return CHUNK_EOF;
195	}
196
197	pkt->stream_index = s->video_stream_index;
198	pkt->pts = s->video_pts;
199
200	av_log(s->avf, AV_LOG_TRACE, "sending video frame with pts %"PRId64"\n", pkt->pts);
201
202	s->video_pts += s->frame_pts_inc;
203
204	chunk_type = CHUNK_VIDEO;
205
206	} else {
207
208	avio_seek(pb, s->next_chunk_offset, SEEK_SET);
209	chunk_type = CHUNK_DONE;
210
211	}
212
213	return chunk_type;
214	}
215
216	static int init_audio(AVFormatContext *s)
217	{
218	IPMVEContext *ipmovie = s->priv_data;
219	AVStream *st = avformat_new_stream(s, NULL);
220	if (!st)
221	return AVERROR(ENOMEM);
222	avpriv_set_pts_info(st, 32, 1, ipmovie->audio_sample_rate);
223	ipmovie->audio_stream_index = st->index;
224	st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
225	st->codecpar->codec_id = ipmovie->audio_type;
226	st->codecpar->codec_tag = 0; /* no tag */
227	st->codecpar->channels = ipmovie->audio_channels;
228	st->codecpar->channel_layout = st->codecpar->channels == 1 ? AV_CH_LAYOUT_MONO :
229	AV_CH_LAYOUT_STEREO;
230	st->codecpar->sample_rate = ipmovie->audio_sample_rate;
231	st->codecpar->bits_per_coded_sample = ipmovie->audio_bits;
232	st->codecpar->bit_rate = st->codecpar->channels * st->codecpar->sample_rate *
233	st->codecpar->bits_per_coded_sample;
234	if (st->codecpar->codec_id == AV_CODEC_ID_INTERPLAY_DPCM)
235	st->codecpar->bit_rate /= 2;
236	st->codecpar->block_align = st->codecpar->channels * st->codecpar->bits_per_coded_sample;
237
238	return 0;
239	}
240
241	/* This function loads and processes a single chunk in an IP movie file.
242	* It returns the type of chunk that was processed. */
243	static int process_ipmovie_chunk(IPMVEContext *s, AVIOContext *pb,
244	AVPacket *pkt)
245	{
246	unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
247	int chunk_type;
248	int chunk_size;
249	unsigned char opcode_preamble[OPCODE_PREAMBLE_SIZE];
250	unsigned char opcode_type;
251	unsigned char opcode_version;
252	int opcode_size;
253	unsigned char scratch[1024];
254	int i, j;
255	int first_color, last_color;
256	int audio_flags;
257	unsigned char r, g, b;
258	unsigned int width, height;
259
260	/* see if there are any pending packets */
261	chunk_type = load_ipmovie_packet(s, pb, pkt);
262	if (chunk_type != CHUNK_DONE)
263	return chunk_type;
264
265	/* read the next chunk, wherever the file happens to be pointing */
266	if (avio_feof(pb))
267	return CHUNK_EOF;
268	if (avio_read(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
269	CHUNK_PREAMBLE_SIZE)
270	return CHUNK_BAD;
271	chunk_size = AV_RL16(&chunk_preamble[0]);
272	chunk_type = AV_RL16(&chunk_preamble[2]);
273
274	av_log(s->avf, AV_LOG_TRACE, "chunk type 0x%04X, 0x%04X bytes: ", chunk_type, chunk_size);
275
276	switch (chunk_type) {
277
278	case CHUNK_INIT_AUDIO:
279	av_log(s->avf, AV_LOG_TRACE, "initialize audio\n");
280	break;
281
282	case CHUNK_AUDIO_ONLY:
283	av_log(s->avf, AV_LOG_TRACE, "audio only\n");
284	break;
285
286	case CHUNK_INIT_VIDEO:
287	av_log(s->avf, AV_LOG_TRACE, "initialize video\n");
288	break;
289
290	case CHUNK_VIDEO:
291	av_log(s->avf, AV_LOG_TRACE, "video (and audio)\n");
292	break;
293
294	case CHUNK_SHUTDOWN:
295	av_log(s->avf, AV_LOG_TRACE, "shutdown\n");
296	break;
297
298	case CHUNK_END:
299	av_log(s->avf, AV_LOG_TRACE, "end\n");
300	break;
301
302	default:
303	av_log(s->avf, AV_LOG_TRACE, "invalid chunk\n");
304	chunk_type = CHUNK_BAD;
305	break;
306
307	}
308
309	while ((chunk_size > 0) && (chunk_type != CHUNK_BAD)) {
310
311	/* read the next chunk, wherever the file happens to be pointing */
312	if (avio_feof(pb)) {
313	chunk_type = CHUNK_EOF;
314	break;
315	}
316	if (avio_read(pb, opcode_preamble, CHUNK_PREAMBLE_SIZE) !=
317	CHUNK_PREAMBLE_SIZE) {
318	chunk_type = CHUNK_BAD;
319	break;
320	}
321
322	opcode_size = AV_RL16(&opcode_preamble[0]);
323	opcode_type = opcode_preamble[2];
324	opcode_version = opcode_preamble[3];
325
326	chunk_size -= OPCODE_PREAMBLE_SIZE;
327	chunk_size -= opcode_size;
328	if (chunk_size < 0) {
329	av_log(s->avf, AV_LOG_TRACE, "chunk_size countdown just went negative\n");
330	chunk_type = CHUNK_BAD;
331	break;
332	}
333
334	av_log(s->avf, AV_LOG_TRACE, " opcode type %02X, version %d, 0x%04X bytes: ",
335	opcode_type, opcode_version, opcode_size);
336	switch (opcode_type) {
337
338	case OPCODE_END_OF_STREAM:
339	av_log(s->avf, AV_LOG_TRACE, "end of stream\n");
340	avio_skip(pb, opcode_size);
341	break;
342
343	case OPCODE_END_OF_CHUNK:
344	av_log(s->avf, AV_LOG_TRACE, "end of chunk\n");
345	avio_skip(pb, opcode_size);
346	break;
347
348	case OPCODE_CREATE_TIMER:
349	av_log(s->avf, AV_LOG_TRACE, "create timer\n");
350	if ((opcode_version > 0) || (opcode_size != 6)) {
351	av_log(s->avf, AV_LOG_TRACE, "bad create_timer opcode\n");
352	chunk_type = CHUNK_BAD;
353	break;
354	}
355	if (avio_read(pb, scratch, opcode_size) !=
356	opcode_size) {
357	chunk_type = CHUNK_BAD;
358	break;
359	}
360	s->frame_pts_inc = ((uint64_t)AV_RL32(&scratch[0])) * AV_RL16(&scratch[4]);
361	break;
362
363	case OPCODE_INIT_AUDIO_BUFFERS:
364	av_log(s->avf, AV_LOG_TRACE, "initialize audio buffers\n");
365	if (opcode_version > 1 || opcode_size > 10 || opcode_size < 6) {
366	av_log(s->avf, AV_LOG_TRACE, "bad init_audio_buffers opcode\n");
367	chunk_type = CHUNK_BAD;
368	break;
369	}
370	if (avio_read(pb, scratch, opcode_size) !=
371	opcode_size) {
372	chunk_type = CHUNK_BAD;
373	break;
374	}
375	s->audio_sample_rate = AV_RL16(&scratch[4]);
376	audio_flags = AV_RL16(&scratch[2]);
377	/* bit 0 of the flags: 0 = mono, 1 = stereo */
378	s->audio_channels = (audio_flags & 1) + 1;
379	/* bit 1 of the flags: 0 = 8 bit, 1 = 16 bit */
380	s->audio_bits = (((audio_flags >> 1) & 1) + 1) * 8;
381	/* bit 2 indicates compressed audio in version 1 opcode */
382	if ((opcode_version == 1) && (audio_flags & 0x4))
383	s->audio_type = AV_CODEC_ID_INTERPLAY_DPCM;
384	else if (s->audio_bits == 16)
385	s->audio_type = AV_CODEC_ID_PCM_S16LE;
386	else
387	s->audio_type = AV_CODEC_ID_PCM_U8;
388	av_log(s->avf, AV_LOG_TRACE, "audio: %d bits, %d Hz, %s, %s format\n",
389	s->audio_bits, s->audio_sample_rate,
390	(s->audio_channels == 2) ? "stereo" : "mono",
391	(s->audio_type == AV_CODEC_ID_INTERPLAY_DPCM) ?
392	"Interplay audio" : "PCM");
393	break;
394
395	case OPCODE_START_STOP_AUDIO:
396	av_log(s->avf, AV_LOG_TRACE, "start/stop audio\n");
397	avio_skip(pb, opcode_size);
398	break;
399
400	case OPCODE_INIT_VIDEO_BUFFERS:
401	av_log(s->avf, AV_LOG_TRACE, "initialize video buffers\n");
402	if ((opcode_version > 2) || (opcode_size > 8) || opcode_size < 4
403	|| opcode_version == 2 && opcode_size < 8
404	) {
405	av_log(s->avf, AV_LOG_TRACE, "bad init_video_buffers opcode\n");
406	chunk_type = CHUNK_BAD;
407	break;
408	}
409	if (avio_read(pb, scratch, opcode_size) !=
410	opcode_size) {
411	chunk_type = CHUNK_BAD;
412	break;
413	}
414	width = AV_RL16(&scratch[0]) * 8;
415	height = AV_RL16(&scratch[2]) * 8;
416	if (width != s->video_width) {
417	s->video_width = width;
418	s->changed++;
419	}
420	if (height != s->video_height) {
421	s->video_height = height;
422	s->changed++;
423	}
424	if (opcode_version < 2 || !AV_RL16(&scratch[6])) {
425	s->video_bpp = 8;
426	} else {
427	s->video_bpp = 16;
428	}
429	av_log(s->avf, AV_LOG_TRACE, "video resolution: %d x %d\n",
430	s->video_width, s->video_height);
431	break;
432
433	case OPCODE_UNKNOWN_06:
434	case OPCODE_UNKNOWN_0E:
435	case OPCODE_UNKNOWN_10:
436	case OPCODE_UNKNOWN_12:
437	case OPCODE_UNKNOWN_13:
438	case OPCODE_UNKNOWN_14:
439	case OPCODE_UNKNOWN_15:
440	av_log(s->avf, AV_LOG_TRACE, "unknown (but documented) opcode %02X\n", opcode_type);
441	avio_skip(pb, opcode_size);
442	break;
443
444	case OPCODE_SEND_BUFFER:
445	av_log(s->avf, AV_LOG_TRACE, "send buffer\n");
446	avio_skip(pb, opcode_size);
447	break;
448
449	case OPCODE_AUDIO_FRAME:
450	av_log(s->avf, AV_LOG_TRACE, "audio frame\n");
451
452	/* log position and move on for now */
453	s->audio_chunk_offset = avio_tell(pb);
454	s->audio_chunk_size = opcode_size;
455	avio_skip(pb, opcode_size);
456	break;
457
458	case OPCODE_SILENCE_FRAME:
459	av_log(s->avf, AV_LOG_TRACE, "silence frame\n");
460	avio_skip(pb, opcode_size);
461	break;
462
463	case OPCODE_INIT_VIDEO_MODE:
464	av_log(s->avf, AV_LOG_TRACE, "initialize video mode\n");
465	avio_skip(pb, opcode_size);
466	break;
467
468	case OPCODE_CREATE_GRADIENT:
469	av_log(s->avf, AV_LOG_TRACE, "create gradient\n");
470	avio_skip(pb, opcode_size);
471	break;
472
473	case OPCODE_SET_PALETTE:
474	av_log(s->avf, AV_LOG_TRACE, "set palette\n");
475	/* check for the logical maximum palette size
476	* (3 * 256 + 4 bytes) */
477	if (opcode_size > 0x304 || opcode_size < 4) {
478	av_log(s->avf, AV_LOG_TRACE, "demux_ipmovie: set_palette opcode with invalid size\n");
479	chunk_type = CHUNK_BAD;
480	break;
481	}
482	if (avio_read(pb, scratch, opcode_size) != opcode_size) {
483	chunk_type = CHUNK_BAD;
484	break;
485	}
486
487	/* load the palette into internal data structure */
488	first_color = AV_RL16(&scratch[0]);
489	last_color = first_color + AV_RL16(&scratch[2]) - 1;
490	/* sanity check (since they are 16 bit values) */
491	if ( (first_color > 0xFF) || (last_color > 0xFF)
492	|| (last_color - first_color + 1)*3 + 4 > opcode_size) {
493	av_log(s->avf, AV_LOG_TRACE, "demux_ipmovie: set_palette indexes out of range (%d -> %d)\n",
494	first_color, last_color);
495	chunk_type = CHUNK_BAD;
496	break;
497	}
498	j = 4; /* offset of first palette data */
499	for (i = first_color; i <= last_color; i++) {
500	/* the palette is stored as a 6-bit VGA palette, thus each
501	* component is shifted up to a 8-bit range */
502	r = scratch[j++] * 4;
503	g = scratch[j++] * 4;
504	b = scratch[j++] * 4;
505	s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
506	s->palette[i] |= s->palette[i] >> 6 & 0x30303;
507	}
508	s->has_palette = 1;
509	break;
510
511	case OPCODE_SET_PALETTE_COMPRESSED:
512	av_log(s->avf, AV_LOG_TRACE, "set palette compressed\n");
513	avio_skip(pb, opcode_size);
514	break;
515
516	case OPCODE_SET_DECODING_MAP:
517	av_log(s->avf, AV_LOG_TRACE, "set decoding map\n");
518
519	/* log position and move on for now */
520	s->decode_map_chunk_offset = avio_tell(pb);
521	s->decode_map_chunk_size = opcode_size;
522	avio_skip(pb, opcode_size);
523	break;
524
525	case OPCODE_VIDEO_DATA:
526	av_log(s->avf, AV_LOG_TRACE, "set video data\n");
527
528	/* log position and move on for now */
529	s->video_chunk_offset = avio_tell(pb);
530	s->video_chunk_size = opcode_size;
531	avio_skip(pb, opcode_size);
532	break;
533
534	default:
535	av_log(s->avf, AV_LOG_TRACE, "*** unknown opcode type\n");
536	chunk_type = CHUNK_BAD;
537	break;
538
539	}
540	}
541
542	if (s->avf->nb_streams == 1 && s->audio_type)
543	init_audio(s->avf);
544
545	/* make a note of where the stream is sitting */
546	s->next_chunk_offset = avio_tell(pb);
547
548	/* dispatch the first of any pending packets */
549	if ((chunk_type == CHUNK_VIDEO) || (chunk_type == CHUNK_AUDIO_ONLY))
550	chunk_type = load_ipmovie_packet(s, pb, pkt);
551
552	return chunk_type;
553	}
554
555	static const char signature[] = "Interplay MVE File\x1A\0\x1A";
556
557	static int ipmovie_probe(AVProbeData *p)
558	{
559	const uint8_t *b = p->buf;
560	const uint8_t *b_end = p->buf + p->buf_size - sizeof(signature);
561	do {
562	if (b[0] == signature[0] && memcmp(b, signature, sizeof(signature)) == 0)
563	return AVPROBE_SCORE_MAX;
564	b++;
565	} while (b < b_end);
566
567	return 0;
568	}
569
570	static int ipmovie_read_header(AVFormatContext *s)
571	{
572	IPMVEContext *ipmovie = s->priv_data;
573	AVIOContext *pb = s->pb;
574	AVPacket pkt;
575	AVStream *st;
576	unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
577	int chunk_type, i;
578	uint8_t signature_buffer[sizeof(signature)];
579
580	ipmovie->avf = s;
581
582	avio_read(pb, signature_buffer, sizeof(signature_buffer));
583	while (memcmp(signature_buffer, signature, sizeof(signature))) {
584	memmove(signature_buffer, signature_buffer + 1, sizeof(signature_buffer) - 1);
585	signature_buffer[sizeof(signature_buffer) - 1] = avio_r8(pb);
586	if (avio_feof(pb))
587	return AVERROR_EOF;
588	}
589	/* initialize private context members */
590	ipmovie->video_pts = ipmovie->audio_frame_count = 0;
591	ipmovie->audio_chunk_offset = ipmovie->video_chunk_offset =
592	ipmovie->decode_map_chunk_offset = 0;
593
594	/* on the first read, this will position the stream at the first chunk */
595	ipmovie->next_chunk_offset = avio_tell(pb) + 4;
596
597	for (i = 0; i < 256; i++)
598	ipmovie->palette[i] = 0xFFU << 24;
599
600	/* process the first chunk which should be CHUNK_INIT_VIDEO */
601	if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_VIDEO)
602	return AVERROR_INVALIDDATA;
603
604	/* peek ahead to the next chunk-- if it is an init audio chunk, process
605	* it; if it is the first video chunk, this is a silent file */
606	if (avio_read(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
607	CHUNK_PREAMBLE_SIZE)
608	return AVERROR(EIO);
609	chunk_type = AV_RL16(&chunk_preamble[2]);
610	avio_seek(pb, -CHUNK_PREAMBLE_SIZE, SEEK_CUR);
611
612	if (chunk_type == CHUNK_VIDEO)
613	ipmovie->audio_type = AV_CODEC_ID_NONE; /* no audio */
614	else if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_AUDIO)
615	return AVERROR_INVALIDDATA;
616
617	/* initialize the stream decoders */
618	st = avformat_new_stream(s, NULL);
619	if (!st)
620	return AVERROR(ENOMEM);
621	avpriv_set_pts_info(st, 63, 1, 1000000);
622	ipmovie->video_stream_index = st->index;
623	st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
624	st->codecpar->codec_id = AV_CODEC_ID_INTERPLAY_VIDEO;
625	st->codecpar->codec_tag = 0; /* no fourcc */
626	st->codecpar->width = ipmovie->video_width;
627	st->codecpar->height = ipmovie->video_height;
628	st->codecpar->bits_per_coded_sample = ipmovie->video_bpp;
629
630	if (ipmovie->audio_type) {
631	return init_audio(s);
632	} else
633	s->ctx_flags |= AVFMTCTX_NOHEADER;
634
635	return 0;
636	}
637
638	static int ipmovie_read_packet(AVFormatContext *s,
639	AVPacket *pkt)
640	{
641	IPMVEContext *ipmovie = s->priv_data;
642	AVIOContext *pb = s->pb;
643	int ret;
644
645	for (;;) {
646	ret = process_ipmovie_chunk(ipmovie, pb, pkt);
647	if (ret == CHUNK_BAD)
648	ret = AVERROR_INVALIDDATA;
649	else if (ret == CHUNK_EOF)
650	ret = AVERROR(EIO);
651	else if (ret == CHUNK_NOMEM)
652	ret = AVERROR(ENOMEM);
653	else if (ret == CHUNK_VIDEO)
654	ret = 0;
655	else if (ret == CHUNK_INIT_VIDEO || ret == CHUNK_INIT_AUDIO)
656	continue;
657	else
658	continue;
659
660	return ret;
661	}
662	}
663
664	AVInputFormat ff_ipmovie_demuxer = {
665	.name = "ipmovie",
666	.long_name = NULL_IF_CONFIG_SMALL("Interplay MVE"),
667	.priv_data_size = sizeof(IPMVEContext),
668	.read_probe = ipmovie_probe,
669	.read_header = ipmovie_read_header,
670	.read_packet = ipmovie_read_packet,
671	};
672