FFmpeg
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 "libavcodec/internal.h"
33 #include "avformat.h"
34 #include "internal.h"
35 
36 #define RIFF_TAG MKTAG('R', 'I', 'F', 'F')
37 #define FOURXMV_TAG MKTAG('4', 'X', 'M', 'V')
38 #define LIST_TAG MKTAG('L', 'I', 'S', 'T')
39 #define HEAD_TAG MKTAG('H', 'E', 'A', 'D')
40 #define TRK__TAG MKTAG('T', 'R', 'K', '_')
41 #define MOVI_TAG MKTAG('M', 'O', 'V', 'I')
42 #define VTRK_TAG MKTAG('V', 'T', 'R', 'K')
43 #define STRK_TAG MKTAG('S', 'T', 'R', 'K')
44 #define std__TAG MKTAG('s', 't', 'd', '_')
45 #define name_TAG MKTAG('n', 'a', 'm', 'e')
46 #define vtrk_TAG MKTAG('v', 't', 'r', 'k')
47 #define strk_TAG MKTAG('s', 't', 'r', 'k')
48 #define ifrm_TAG MKTAG('i', 'f', 'r', 'm')
49 #define pfrm_TAG MKTAG('p', 'f', 'r', 'm')
50 #define cfrm_TAG MKTAG('c', 'f', 'r', 'm')
51 #define ifr2_TAG MKTAG('i', 'f', 'r', '2')
52 #define pfr2_TAG MKTAG('p', 'f', 'r', '2')
53 #define cfr2_TAG MKTAG('c', 'f', 'r', '2')
54 #define snd__TAG MKTAG('s', 'n', 'd', '_')
55 
56 #define vtrk_SIZE 0x44
57 #define strk_SIZE 0x28
58 
59 #define GET_LIST_HEADER() \
60  fourcc_tag = avio_rl32(pb); \
61  size = avio_rl32(pb); \
62  if (fourcc_tag != LIST_TAG) \
63  return AVERROR_INVALIDDATA; \
64  fourcc_tag = avio_rl32(pb);
65 
66 typedef struct AudioTrack {
68  int bits;
69  int channels;
71  int adpcm;
72  int64_t audio_pts;
73 } AudioTrack;
74 
75 typedef struct FourxmDemuxContext {
79 
80  int64_t video_pts;
83 
84 static int fourxm_probe(const AVProbeData *p)
85 {
86  if ((AV_RL32(&p->buf[0]) != RIFF_TAG) ||
87  (AV_RL32(&p->buf[8]) != FOURXMV_TAG))
88  return 0;
89 
90  return AVPROBE_SCORE_MAX;
91 }
92 
94  FourxmDemuxContext *fourxm, uint8_t *buf, int size,
95  int left)
96 {
97  AVStream *st;
98  /* check that there is enough data */
99  if (size != vtrk_SIZE || left < size + 8) {
100  return AVERROR_INVALIDDATA;
101  }
102 
103  /* allocate a new AVStream */
104  st = avformat_new_stream(s, NULL);
105  if (!st)
106  return AVERROR(ENOMEM);
107 
108  avpriv_set_pts_info(st, 60, fourxm->fps.den, fourxm->fps.num);
109 
110  fourxm->video_stream_index = st->index;
111 
114 
116  if (!st->codecpar->extradata)
117  return AVERROR(ENOMEM);
118  st->codecpar->extradata_size = 4;
119  AV_WL32(st->codecpar->extradata, AV_RL32(buf + 16));
120  st->codecpar->width = AV_RL32(buf + 36);
121  st->codecpar->height = AV_RL32(buf + 40);
122 
123  return 0;
124 }
125 
126 
128  FourxmDemuxContext *fourxm, uint8_t *buf, int size,
129  int left)
130 {
131  AVStream *st;
132  int track;
133  /* check that there is enough data */
134  if (size != strk_SIZE || left < size + 8)
135  return AVERROR_INVALIDDATA;
136 
137  track = AV_RL32(buf + 8);
138  if ((unsigned)track >= UINT_MAX / sizeof(AudioTrack) - 1) {
139  av_log(s, AV_LOG_ERROR, "current_track too large\n");
140  return AVERROR_INVALIDDATA;
141  }
142 
143  if (track + 1 > fourxm->track_count) {
144  if (av_reallocp_array(&fourxm->tracks, track + 1, sizeof(AudioTrack)))
145  return AVERROR(ENOMEM);
146  memset(&fourxm->tracks[fourxm->track_count], 0,
147  sizeof(AudioTrack) * (track + 1 - fourxm->track_count));
148  fourxm->track_count = track + 1;
149  }
150  fourxm->tracks[track].adpcm = AV_RL32(buf + 12);
151  fourxm->tracks[track].channels = AV_RL32(buf + 36);
152  fourxm->tracks[track].sample_rate = AV_RL32(buf + 40);
153  fourxm->tracks[track].bits = AV_RL32(buf + 44);
154  fourxm->tracks[track].audio_pts = 0;
155 
156  if (fourxm->tracks[track].channels <= 0 ||
157  fourxm->tracks[track].channels > FF_SANE_NB_CHANNELS ||
158  fourxm->tracks[track].sample_rate <= 0 ||
159  fourxm->tracks[track].bits <= 0 ||
160  fourxm->tracks[track].bits > INT_MAX / FF_SANE_NB_CHANNELS) {
161  av_log(s, AV_LOG_ERROR, "audio header invalid\n");
162  return AVERROR_INVALIDDATA;
163  }
164  if (!fourxm->tracks[track].adpcm && fourxm->tracks[track].bits<8) {
165  av_log(s, AV_LOG_ERROR, "bits unspecified for non ADPCM\n");
166  return AVERROR_INVALIDDATA;
167  }
168 
169  if (fourxm->tracks[track].sample_rate > INT64_MAX / fourxm->tracks[track].bits / fourxm->tracks[track].channels) {
170  av_log(s, AV_LOG_ERROR, "Overflow during bit rate calculation %d * %d * %d\n",
171  fourxm->tracks[track].sample_rate, fourxm->tracks[track].bits, fourxm->tracks[track].channels);
172  return AVERROR_INVALIDDATA;
173  }
174 
175  /* allocate a new AVStream */
176  st = avformat_new_stream(s, NULL);
177  if (!st)
178  return AVERROR(ENOMEM);
179 
180  st->id = track;
181  avpriv_set_pts_info(st, 60, 1, fourxm->tracks[track].sample_rate);
182 
183  fourxm->tracks[track].stream_index = st->index;
184 
186  st->codecpar->codec_tag = 0;
187  st->codecpar->channels = fourxm->tracks[track].channels;
188  st->codecpar->sample_rate = fourxm->tracks[track].sample_rate;
189  st->codecpar->bits_per_coded_sample = fourxm->tracks[track].bits;
190  st->codecpar->bit_rate = (int64_t)st->codecpar->channels *
191  st->codecpar->sample_rate *
193  st->codecpar->block_align = st->codecpar->channels *
195 
196  if (fourxm->tracks[track].adpcm){
198  } else if (st->codecpar->bits_per_coded_sample == 8) {
200  } else
202 
203  return 0;
204 }
205 
207 {
208  AVIOContext *pb = s->pb;
209  unsigned int fourcc_tag;
210  unsigned int size;
211  int header_size;
212  FourxmDemuxContext *fourxm = s->priv_data;
213  unsigned char *header;
214  int i, ret;
215 
216  fourxm->track_count = 0;
217  fourxm->tracks = NULL;
218  fourxm->fps = (AVRational){1,1};
219 
220  /* skip the first 3 32-bit numbers */
221  avio_skip(pb, 12);
222 
223  /* check for LIST-HEAD */
224  GET_LIST_HEADER();
225  header_size = size - 4;
226  if (fourcc_tag != HEAD_TAG || header_size < 0)
227  return AVERROR_INVALIDDATA;
228 
229  /* allocate space for the header and load the whole thing */
230  header = av_malloc(header_size);
231  if (!header)
232  return AVERROR(ENOMEM);
233  if (avio_read(pb, header, header_size) != header_size) {
234  av_free(header);
235  return AVERROR(EIO);
236  }
237 
238  /* take the lazy approach and search for any and all vtrk and strk chunks */
239  for (i = 0; i < header_size - 8; i++) {
240  fourcc_tag = AV_RL32(&header[i]);
241  size = AV_RL32(&header[i + 4]);
242  if (size > header_size - i - 8 && (fourcc_tag == vtrk_TAG || fourcc_tag == strk_TAG)) {
243  av_log(s, AV_LOG_ERROR, "chunk larger than array %d>%d\n", size, header_size - i - 8);
244  return AVERROR_INVALIDDATA;
245  }
246 
247  if (fourcc_tag == std__TAG) {
248  if (header_size - i < 16) {
249  av_log(s, AV_LOG_ERROR, "std TAG truncated\n");
250  ret = AVERROR_INVALIDDATA;
251  goto fail;
252  }
253  fourxm->fps = av_d2q(av_int2float(AV_RL32(&header[i + 12])), 10000);
254  } else if (fourcc_tag == vtrk_TAG) {
255  if ((ret = parse_vtrk(s, fourxm, header + i, size,
256  header_size - i)) < 0)
257  goto fail;
258 
259  i += 8 + size;
260  } else if (fourcc_tag == strk_TAG) {
261  if ((ret = parse_strk(s, fourxm, header + i, size,
262  header_size - i)) < 0)
263  goto fail;
264 
265  i += 8 + size;
266  }
267  }
268 
269  /* skip over the LIST-MOVI chunk (which is where the stream should be */
270  GET_LIST_HEADER();
271  if (fourcc_tag != MOVI_TAG) {
272  ret = AVERROR_INVALIDDATA;
273  goto fail;
274  }
275 
276  av_free(header);
277  /* initialize context members */
278  fourxm->video_pts = -1; /* first frame will push to 0 */
279 
280  return 0;
281 fail:
282  av_freep(&fourxm->tracks);
283  av_free(header);
284  return ret;
285 }
286 
288  AVPacket *pkt)
289 {
290  FourxmDemuxContext *fourxm = s->priv_data;
291  AVIOContext *pb = s->pb;
292  unsigned int fourcc_tag;
293  unsigned int size;
294  int ret = 0;
295  unsigned int track_number;
296  int packet_read = 0;
297  unsigned char header[8];
298  int audio_frame_count;
299 
300  while (!packet_read) {
301  if ((ret = avio_read(s->pb, header, 8)) < 0)
302  return ret;
303  fourcc_tag = AV_RL32(&header[0]);
304  size = AV_RL32(&header[4]);
305  if (avio_feof(pb))
306  return AVERROR(EIO);
307  switch (fourcc_tag) {
308  case LIST_TAG:
309  /* this is a good time to bump the video pts */
310  fourxm->video_pts++;
311 
312  /* skip the LIST-* tag and move on to the next fourcc */
313  avio_rl32(pb);
314  break;
315 
316  case ifrm_TAG:
317  case pfrm_TAG:
318  case cfrm_TAG:
319  case ifr2_TAG:
320  case pfr2_TAG:
321  case cfr2_TAG:
322  /* allocate 8 more bytes than 'size' to account for fourcc
323  * and size */
324  if (size + 8 < size || av_new_packet(pkt, size + 8))
325  return AVERROR(EIO);
326  pkt->stream_index = fourxm->video_stream_index;
327  pkt->pts = fourxm->video_pts;
328  pkt->pos = avio_tell(s->pb);
329  memcpy(pkt->data, header, 8);
330  ret = avio_read(s->pb, &pkt->data[8], size);
331 
332  if (ret < 0) {
333  av_packet_unref(pkt);
334  } else {
335  packet_read = 1;
336  av_shrink_packet(pkt, ret + 8);
337  }
338  break;
339 
340  case snd__TAG:
341  track_number = avio_rl32(pb);
342  avio_skip(pb, 4);
343  size -= 8;
344 
345  if (track_number < fourxm->track_count &&
346  fourxm->tracks[track_number].channels > 0) {
347  ret = av_get_packet(s->pb, pkt, size);
348  if (ret < 0)
349  return AVERROR(EIO);
350  pkt->stream_index =
351  fourxm->tracks[track_number].stream_index;
352  pkt->pts = fourxm->tracks[track_number].audio_pts;
353  packet_read = 1;
354 
355  /* pts accounting */
356  audio_frame_count = size;
357  if (fourxm->tracks[track_number].adpcm)
358  audio_frame_count -= 2 * (fourxm->tracks[track_number].channels);
359  audio_frame_count /= fourxm->tracks[track_number].channels;
360  if (fourxm->tracks[track_number].adpcm) {
361  audio_frame_count *= 2;
362  } else
363  audio_frame_count /=
364  (fourxm->tracks[track_number].bits / 8);
365  fourxm->tracks[track_number].audio_pts += audio_frame_count;
366  } else {
367  avio_skip(pb, size);
368  }
369  break;
370 
371  default:
372  avio_skip(pb, size);
373  break;
374  }
375  }
376  return ret;
377 }
378 
380 {
381  FourxmDemuxContext *fourxm = s->priv_data;
382 
383  av_freep(&fourxm->tracks);
384 
385  return 0;
386 }
387 
389  .name = "4xm",
390  .long_name = NULL_IF_CONFIG_SMALL("4X Technologies"),
391  .priv_data_size = sizeof(FourxmDemuxContext),
396 };
#define FF_SANE_NB_CHANNELS
Definition: internal.h:86
#define NULL
Definition: coverity.c:32
int sample_rate
Definition: 4xm.c:67
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int64_t audio_pts
Definition: 4xm.c:72
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1497
void av_shrink_packet(AVPacket *pkt, int size)
Reduce packet size, correctly zeroing padding.
Definition: avpacket.c:101
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4892
#define ifr2_TAG
Definition: 4xm.c:51
static av_always_inline float av_int2float(uint32_t i)
Reinterpret a 32-bit integer as a float.
Definition: intfloat.h:40
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int num
Numerator.
Definition: rational.h:59
int index
stream index in AVFormatContext
Definition: avformat.h:882
static int audio_frame_count
#define strk_SIZE
Definition: 4xm.c:57
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
static int parse_vtrk(AVFormatContext *s, FourxmDemuxContext *fourxm, uint8_t *buf, int size, int left)
Definition: 4xm.c:93
int channels
Definition: 4xm.c:69
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
static AVPacket pkt
AVRational fps
Definition: 4xm.c:81
static int fourxm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: 4xm.c:287
int adpcm
Definition: 4xm.c:71
Format I/O context.
Definition: avformat.h:1358
#define cfrm_TAG
Definition: 4xm.c:50
uint8_t
#define av_malloc(s)
int width
Video only.
Definition: avcodec.h:4023
#define FOURXMV_TAG
Definition: 4xm.c:37
int id
Format-specific stream ID.
Definition: avformat.h:888
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4465
static int fourxm_probe(const AVProbeData *p)
Definition: 4xm.c:84
#define vtrk_SIZE
Definition: 4xm.c:56
#define strk_TAG
Definition: 4xm.c:47
uint8_t * data
Definition: avcodec.h:1477
Definition: 4xm.c:66
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
AVInputFormat ff_fourxm_demuxer
Definition: 4xm.c:388
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:650
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3986
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:772
#define RIFF_TAG
Definition: 4xm.c:36
int video_stream_index
Definition: 4xm.c:76
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
#define fail()
Definition: checkasm.h:120
int extradata_size
Size of the extradata content in bytes.
Definition: avcodec.h:3975
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
Allocate, reallocate, or free an array through a pointer to a pointer.
Definition: mem.c:205
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
int block_align
Audio only.
Definition: avcodec.h:4074
static int fourxm_read_close(AVFormatContext *s)
Definition: 4xm.c:379
static int parse_strk(AVFormatContext *s, FourxmDemuxContext *fourxm, uint8_t *buf, int size, int left)
Definition: 4xm.c:127
int stream_index
Definition: 4xm.c:70
int64_t video_pts
Definition: 4xm.c:80
int track_count
Definition: 4xm.c:77
#define pfrm_TAG
Definition: 4xm.c:49
#define s(width, name)
Definition: cbs_vp9.c:257
AudioTrack * tracks
Definition: 4xm.c:78
#define MOVI_TAG
Definition: 4xm.c:41
static int fourxm_read_header(AVFormatContext *s)
Definition: 4xm.c:206
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
if(ret)
Stream structure.
Definition: avformat.h:881
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2]...the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so...,+,-,+,-,+,+,-,+,-,+,...hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32-hcoeff[1]-hcoeff[2]-...a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2}an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||.........intra?||||:Block01:yes no||||:Block02:.................||||:Block03::y DC::ref index:||||:Block04::cb DC::motion x:||||.........:cr DC::motion y:||||.................|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------------------------------|||Y subbands||Cb subbands||Cr subbands||||------||------||------|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||------||------||------||||------||------||------|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||------||------||------||||------||------||------|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||------||------||------||||------||------||------|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------------------------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction------------|\Dequantization-------------------\||Reference frames|\IDWT|--------------|Motion\|||Frame 0||Frame 1||Compensation.OBMC v-------|--------------|--------------.\------> Frame n output Frame Frame<----------------------------------/|...|-------------------Range Coder:============Binary Range Coder:-------------------The implemented range coder is an adapted version based upon"Range encoding: an algorithm for removing redundancy from a digitised message."by G.N.N.Martin.The symbols encoded by the Snow range coder are bits(0|1).The associated probabilities are not fix but change depending on the symbol mix seen so far.bit seen|new state---------+-----------------------------------------------0|256-state_transition_table[256-old_state];1|state_transition_table[old_state];state_transition_table={0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:-------------------------FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1.the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:206
void * buf
Definition: avisynth_c.h:766
#define LIST_TAG
Definition: 4xm.c:38
#define std__TAG
Definition: 4xm.c:44
Rational number (pair of numerator and denominator).
Definition: rational.h:58
#define ifrm_TAG
Definition: 4xm.c:48
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define snd__TAG
Definition: 4xm.c:54
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVRational av_d2q(double d, int max)
Convert a double precision floating point number to a rational.
Definition: rational.c:106
int sample_rate
Audio only.
Definition: avcodec.h:4067
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
common internal api header.
#define vtrk_TAG
Definition: 4xm.c:46
int bits
Definition: 4xm.c:68
int den
Denominator.
Definition: rational.h:60
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:790
#define GET_LIST_HEADER()
Definition: 4xm.c:59
#define av_free(p)
void * priv_data
Format private data.
Definition: avformat.h:1386
#define cfr2_TAG
Definition: 4xm.c:53
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3999
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3971
#define pfr2_TAG
Definition: 4xm.c:52
int channels
Audio only.
Definition: avcodec.h:4063
#define av_freep(p)
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: avcodec.h:3961
int stream_index
Definition: avcodec.h:1479
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
This structure stores compressed data.
Definition: avcodec.h:1454
#define HEAD_TAG
Definition: 4xm.c:39
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
#define AV_WL32(p, v)
Definition: intreadwrite.h:426