FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
4xm.c
Go to the documentation of this file.
1 /*
2  * 4X Technologies .4xm File Demuxer (no muxer)
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  * 4X Technologies file demuxer
25  * by Mike Melanson (melanson@pcisys.net)
26  * for more information on the .4xm file format, visit:
27  * http://www.pcisys.net/~melanson/codecs/
28  */
29 
30 #include "libavutil/intreadwrite.h"
31 #include "libavutil/intfloat.h"
32 #include "avformat.h"
33 #include "internal.h"
34 
35 #define RIFF_TAG MKTAG('R', 'I', 'F', 'F')
36 #define FOURXMV_TAG MKTAG('4', 'X', 'M', 'V')
37 #define LIST_TAG MKTAG('L', 'I', 'S', 'T')
38 #define HEAD_TAG MKTAG('H', 'E', 'A', 'D')
39 #define TRK__TAG MKTAG('T', 'R', 'K', '_')
40 #define MOVI_TAG MKTAG('M', 'O', 'V', 'I')
41 #define VTRK_TAG MKTAG('V', 'T', 'R', 'K')
42 #define STRK_TAG MKTAG('S', 'T', 'R', 'K')
43 #define std__TAG MKTAG('s', 't', 'd', '_')
44 #define name_TAG MKTAG('n', 'a', 'm', 'e')
45 #define vtrk_TAG MKTAG('v', 't', 'r', 'k')
46 #define strk_TAG MKTAG('s', 't', 'r', 'k')
47 #define ifrm_TAG MKTAG('i', 'f', 'r', 'm')
48 #define pfrm_TAG MKTAG('p', 'f', 'r', 'm')
49 #define cfrm_TAG MKTAG('c', 'f', 'r', 'm')
50 #define ifr2_TAG MKTAG('i', 'f', 'r', '2')
51 #define pfr2_TAG MKTAG('p', 'f', 'r', '2')
52 #define cfr2_TAG MKTAG('c', 'f', 'r', '2')
53 #define snd__TAG MKTAG('s', 'n', 'd', '_')
54 
55 #define vtrk_SIZE 0x44
56 #define strk_SIZE 0x28
57 
58 #define GET_LIST_HEADER() \
59  fourcc_tag = avio_rl32(pb); \
60  size = avio_rl32(pb); \
61  if (fourcc_tag != LIST_TAG) \
62  return AVERROR_INVALIDDATA; \
63  fourcc_tag = avio_rl32(pb);
64 
65 typedef struct AudioTrack {
66  int sample_rate;
67  int bits;
68  int channels;
69  int stream_index;
70  int adpcm;
71  int64_t audio_pts;
72 } AudioTrack;
73 
74 typedef struct FourxmDemuxContext {
75  int video_stream_index;
76  int track_count;
77  AudioTrack *tracks;
78 
79  int64_t video_pts;
80  float fps;
81 } FourxmDemuxContext;
82 
83 static int fourxm_probe(AVProbeData *p)
84 {
85  if ((AV_RL32(&p->buf[0]) != RIFF_TAG) ||
86  (AV_RL32(&p->buf[8]) != FOURXMV_TAG))
87  return 0;
88 
89  return AVPROBE_SCORE_MAX;
90 }
91 
92 static int parse_vtrk(AVFormatContext *s,
93  FourxmDemuxContext *fourxm, uint8_t *buf, int size,
94  int left)
95 {
96  AVStream *st;
97  /* check that there is enough data */
98  if (size != vtrk_SIZE || left < size + 8) {
99  return AVERROR_INVALIDDATA;
100  }
101 
102  /* allocate a new AVStream */
103  st = avformat_new_stream(s, NULL);
104  if (!st)
105  return AVERROR(ENOMEM);
106 
107  avpriv_set_pts_info(st, 60, 1, fourxm->fps);
108 
109  fourxm->video_stream_index = st->index;
110 
111  st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
112  st->codec->codec_id = AV_CODEC_ID_4XM;
113 
114  st->codec->extradata = av_mallocz(4 + FF_INPUT_BUFFER_PADDING_SIZE);
115  if (!st->codec->extradata)
116  return AVERROR(ENOMEM);
117  st->codec->extradata_size = 4;
118  AV_WL32(st->codec->extradata, AV_RL32(buf + 16));
119  st->codec->width = AV_RL32(buf + 36);
120  st->codec->height = AV_RL32(buf + 40);
121 
122  return 0;
123 }
124 
125 
126 static int parse_strk(AVFormatContext *s,
127  FourxmDemuxContext *fourxm, uint8_t *buf, int size,
128  int left)
129 {
130  AVStream *st;
131  int track;
132  /* check that there is enough data */
133  if (size != strk_SIZE || left < size + 8)
134  return AVERROR_INVALIDDATA;
135 
136  track = AV_RL32(buf + 8);
137  if ((unsigned)track >= UINT_MAX / sizeof(AudioTrack) - 1) {
138  av_log(s, AV_LOG_ERROR, "current_track too large\n");
139  return AVERROR_INVALIDDATA;
140  }
141 
142  if (track + 1 > fourxm->track_count) {
143  if (av_reallocp_array(&fourxm->tracks, track + 1, sizeof(AudioTrack)))
144  return AVERROR(ENOMEM);
145  memset(&fourxm->tracks[fourxm->track_count], 0,
146  sizeof(AudioTrack) * (track + 1 - fourxm->track_count));
147  fourxm->track_count = track + 1;
148  }
149  fourxm->tracks[track].adpcm = AV_RL32(buf + 12);
150  fourxm->tracks[track].channels = AV_RL32(buf + 36);
151  fourxm->tracks[track].sample_rate = AV_RL32(buf + 40);
152  fourxm->tracks[track].bits = AV_RL32(buf + 44);
153  fourxm->tracks[track].audio_pts = 0;
154 
155  if (fourxm->tracks[track].channels <= 0 ||
156  fourxm->tracks[track].sample_rate <= 0 ||
157  fourxm->tracks[track].bits <= 0) {
158  av_log(s, AV_LOG_ERROR, "audio header invalid\n");
159  return AVERROR_INVALIDDATA;
160  }
161  if (!fourxm->tracks[track].adpcm && fourxm->tracks[track].bits<8) {
162  av_log(s, AV_LOG_ERROR, "bits unspecified for non ADPCM\n");
163  return AVERROR_INVALIDDATA;
164  }
165 
166  /* allocate a new AVStream */
167  st = avformat_new_stream(s, NULL);
168  if (!st)
169  return AVERROR(ENOMEM);
170 
171  st->id = track;
172  avpriv_set_pts_info(st, 60, 1, fourxm->tracks[track].sample_rate);
173 
174  fourxm->tracks[track].stream_index = st->index;
175 
176  st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
177  st->codec->codec_tag = 0;
178  st->codec->channels = fourxm->tracks[track].channels;
179  st->codec->sample_rate = fourxm->tracks[track].sample_rate;
180  st->codec->bits_per_coded_sample = fourxm->tracks[track].bits;
181  st->codec->bit_rate = st->codec->channels *
182  st->codec->sample_rate *
183  st->codec->bits_per_coded_sample;
184  st->codec->block_align = st->codec->channels *
185  st->codec->bits_per_coded_sample;
186 
187  if (fourxm->tracks[track].adpcm){
188  st->codec->codec_id = AV_CODEC_ID_ADPCM_4XM;
189  } else if (st->codec->bits_per_coded_sample == 8) {
190  st->codec->codec_id = AV_CODEC_ID_PCM_U8;
191  } else
192  st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;
193 
194  return 0;
195 }
196 
197 static int fourxm_read_header(AVFormatContext *s)
198 {
199  AVIOContext *pb = s->pb;
200  unsigned int fourcc_tag;
201  unsigned int size;
202  int header_size;
203  FourxmDemuxContext *fourxm = s->priv_data;
204  unsigned char *header;
205  int i, ret;
206 
207  fourxm->track_count = 0;
208  fourxm->tracks = NULL;
209  fourxm->fps = 1.0;
210 
211  /* skip the first 3 32-bit numbers */
212  avio_skip(pb, 12);
213 
214  /* check for LIST-HEAD */
215  GET_LIST_HEADER();
216  header_size = size - 4;
217  if (fourcc_tag != HEAD_TAG || header_size < 0)
218  return AVERROR_INVALIDDATA;
219 
220  /* allocate space for the header and load the whole thing */
221  header = av_malloc(header_size);
222  if (!header)
223  return AVERROR(ENOMEM);
224  if (avio_read(pb, header, header_size) != header_size) {
225  av_free(header);
226  return AVERROR(EIO);
227  }
228 
229  /* take the lazy approach and search for any and all vtrk and strk chunks */
230  for (i = 0; i < header_size - 8; i++) {
231  fourcc_tag = AV_RL32(&header[i]);
232  size = AV_RL32(&header[i + 4]);
233  if (size > header_size - i - 8 && (fourcc_tag == vtrk_TAG || fourcc_tag == strk_TAG)) {
234  av_log(s, AV_LOG_ERROR, "chunk larger than array %d>%d\n", size, header_size - i - 8);
235  return AVERROR_INVALIDDATA;
236  }
237 
238  if (fourcc_tag == std__TAG) {
239  if (header_size - i < 16) {
240  av_log(s, AV_LOG_ERROR, "std TAG truncated\n");
241  ret = AVERROR_INVALIDDATA;
242  goto fail;
243  }
244  fourxm->fps = av_int2float(AV_RL32(&header[i + 12]));
245  } else if (fourcc_tag == vtrk_TAG) {
246  if ((ret = parse_vtrk(s, fourxm, header + i, size,
247  header_size - i)) < 0)
248  goto fail;
249 
250  i += 8 + size;
251  } else if (fourcc_tag == strk_TAG) {
252  if ((ret = parse_strk(s, fourxm, header + i, size,
253  header_size - i)) < 0)
254  goto fail;
255 
256  i += 8 + size;
257  }
258  }
259 
260  /* skip over the LIST-MOVI chunk (which is where the stream should be */
261  GET_LIST_HEADER();
262  if (fourcc_tag != MOVI_TAG) {
263  ret = AVERROR_INVALIDDATA;
264  goto fail;
265  }
266 
267  av_free(header);
268  /* initialize context members */
269  fourxm->video_pts = -1; /* first frame will push to 0 */
270 
271  return 0;
272 fail:
273  av_freep(&fourxm->tracks);
274  av_free(header);
275  return ret;
276 }
277 
278 static int fourxm_read_packet(AVFormatContext *s,
279  AVPacket *pkt)
280 {
281  FourxmDemuxContext *fourxm = s->priv_data;
282  AVIOContext *pb = s->pb;
283  unsigned int fourcc_tag;
284  unsigned int size;
285  int ret = 0;
286  unsigned int track_number;
287  int packet_read = 0;
288  unsigned char header[8];
289  int audio_frame_count;
290 
291  while (!packet_read) {
292  if ((ret = avio_read(s->pb, header, 8)) < 0)
293  return ret;
294  fourcc_tag = AV_RL32(&header[0]);
295  size = AV_RL32(&header[4]);
296  if (avio_feof(pb))
297  return AVERROR(EIO);
298  switch (fourcc_tag) {
299  case LIST_TAG:
300  /* this is a good time to bump the video pts */
301  fourxm->video_pts++;
302 
303  /* skip the LIST-* tag and move on to the next fourcc */
304  avio_rl32(pb);
305  break;
306 
307  case ifrm_TAG:
308  case pfrm_TAG:
309  case cfrm_TAG:
310  case ifr2_TAG:
311  case pfr2_TAG:
312  case cfr2_TAG:
313  /* allocate 8 more bytes than 'size' to account for fourcc
314  * and size */
315  if (size + 8 < size || av_new_packet(pkt, size + 8))
316  return AVERROR(EIO);
317  pkt->stream_index = fourxm->video_stream_index;
318  pkt->pts = fourxm->video_pts;
319  pkt->pos = avio_tell(s->pb);
320  memcpy(pkt->data, header, 8);
321  ret = avio_read(s->pb, &pkt->data[8], size);
322 
323  if (ret < 0) {
324  av_free_packet(pkt);
325  } else {
326  packet_read = 1;
327  av_shrink_packet(pkt, ret + 8);
328  }
329  break;
330 
331  case snd__TAG:
332  track_number = avio_rl32(pb);
333  avio_skip(pb, 4);
334  size -= 8;
335 
336  if (track_number < fourxm->track_count &&
337  fourxm->tracks[track_number].channels > 0) {
338  ret = av_get_packet(s->pb, pkt, size);
339  if (ret < 0)
340  return AVERROR(EIO);
341  pkt->stream_index =
342  fourxm->tracks[track_number].stream_index;
343  pkt->pts = fourxm->tracks[track_number].audio_pts;
344  packet_read = 1;
345 
346  /* pts accounting */
347  audio_frame_count = size;
348  if (fourxm->tracks[track_number].adpcm)
349  audio_frame_count -= 2 * (fourxm->tracks[track_number].channels);
350  audio_frame_count /= fourxm->tracks[track_number].channels;
351  if (fourxm->tracks[track_number].adpcm) {
352  audio_frame_count *= 2;
353  } else
354  audio_frame_count /=
355  (fourxm->tracks[track_number].bits / 8);
356  fourxm->tracks[track_number].audio_pts += audio_frame_count;
357  } else {
358  avio_skip(pb, size);
359  }
360  break;
361 
362  default:
363  avio_skip(pb, size);
364  break;
365  }
366  }
367  return ret;
368 }
369 
370 static int fourxm_read_close(AVFormatContext *s)
371 {
372  FourxmDemuxContext *fourxm = s->priv_data;
373 
374  av_freep(&fourxm->tracks);
375 
376  return 0;
377 }
378 
379 AVInputFormat ff_fourxm_demuxer = {
380  .name = "4xm",
381  .long_name = NULL_IF_CONFIG_SMALL("4X Technologies"),
382  .priv_data_size = sizeof(FourxmDemuxContext),
383  .read_probe = fourxm_probe,
384  .read_header = fourxm_read_header,
385  .read_packet = fourxm_read_packet,
386  .read_close = fourxm_read_close,
387 };
Generated on Sun Mar 8 2015 02:34:46 for FFmpeg by   doxygen 1.8.2