FFmpeg
hnm4video.c
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1 /*
2  * Cryo Interactive Entertainment HNM4 video decoder
3  *
4  * Copyright (c) 2012 David Kment
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include <string.h>
24 
25 #include "libavutil/imgutils.h"
26 #include "libavutil/internal.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/mem.h"
29 #include "avcodec.h"
30 #include "bytestream.h"
31 #include "codec_internal.h"
32 #include "decode.h"
33 
34 #define HNM4_CHUNK_ID_PL 19536
35 #define HNM4_CHUNK_ID_IZ 23113
36 #define HNM4_CHUNK_ID_IU 21833
37 #define HNM4_CHUNK_ID_SD 17491
38 
39 typedef struct Hnm4VideoContext {
40  uint8_t version;
41  int width;
42  int height;
43  uint8_t *current;
44  uint8_t *previous;
45  uint8_t *buffer1;
46  uint8_t *buffer2;
47  uint8_t *processed;
48  uint32_t palette[256];
50 
51 static int getbit(GetByteContext *gb, uint32_t *bitbuf, int *bits)
52 {
53  int ret;
54 
55  if (!*bits) {
56  *bitbuf = bytestream2_get_le32(gb);
57  *bits = 32;
58  }
59 
60  ret = *bitbuf >> 31;
61  *bitbuf <<= 1;
62  (*bits)--;
63 
64  return ret;
65 }
66 
67 static void unpack_intraframe(AVCodecContext *avctx, const uint8_t *src,
68  uint32_t size)
69 {
70  Hnm4VideoContext *hnm = avctx->priv_data;
71  GetByteContext gb;
72  uint32_t bitbuf = 0, writeoffset = 0, count = 0;
73  uint16_t word;
75  int bits = 0;
76 
77  bytestream2_init(&gb, src, size);
78 
79  while (bytestream2_tell(&gb) < size) {
80  if (getbit(&gb, &bitbuf, &bits)) {
81  if (writeoffset >= hnm->width * hnm->height) {
82  av_log(avctx, AV_LOG_ERROR,
83  "Attempting to write out of bounds\n");
84  break;
85  }
86  hnm->current[writeoffset++] = bytestream2_get_byte(&gb);
87  } else {
88  if (getbit(&gb, &bitbuf, &bits)) {
89  word = bytestream2_get_le16(&gb);
90  count = word & 0x07;
91  offset = (word >> 3) - 0x2000;
92  if (!count)
93  count = bytestream2_get_byte(&gb);
94  if (!count)
95  return;
96  } else {
97  count = getbit(&gb, &bitbuf, &bits) * 2;
98  count += getbit(&gb, &bitbuf, &bits);
99  offset = bytestream2_get_byte(&gb) - 0x0100;
100  }
101  count += 2;
102  offset += writeoffset;
103  if (offset < 0 || offset + count >= hnm->width * hnm->height) {
104  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
105  break;
106  } else if (writeoffset + count >= hnm->width * hnm->height) {
107  av_log(avctx, AV_LOG_ERROR,
108  "Attempting to write out of bounds\n");
109  break;
110  }
111  while (count--) {
112  hnm->current[writeoffset++] = hnm->current[offset++];
113  }
114  }
115  }
116 }
117 
119 {
120  Hnm4VideoContext *hnm = avctx->priv_data;
121  uint32_t x, y, src_y;
122  int width = hnm->width;
123 
124  for (y = 0; y < hnm->height; y++) {
125  uint8_t *dst = hnm->processed + y * width;
126  const uint8_t *src = hnm->current;
127  src_y = y - (y % 2);
128  src += src_y * width + (y % 2);
129  for (x = 0; x < width; x++) {
130  dst[x] = *src;
131  src += 2;
132  }
133  }
134 }
135 
137 {
138  Hnm4VideoContext *hnm = avctx->priv_data;
139  uint8_t *src = hnm->processed;
140  uint8_t *dst = frame->data[0];
141  int y;
142 
143  for (y = 0; y < hnm->height; y++) {
144  memcpy(dst, src, hnm->width);
145  src += hnm->width;
146  dst += frame->linesize[0];
147  }
148 }
149 
150 static int decode_interframe_v4(AVCodecContext *avctx, const uint8_t *src, uint32_t size)
151 {
152  Hnm4VideoContext *hnm = avctx->priv_data;
153  GetByteContext gb;
154  uint32_t writeoffset = 0;
155  int count, left, offset;
156  uint8_t tag, previous, backline, backward, swap;
157 
158  bytestream2_init(&gb, src, size);
159 
160  while (bytestream2_tell(&gb) < size) {
161  count = bytestream2_peek_byte(&gb) & 0x1F;
162  if (count == 0) {
163  tag = bytestream2_get_byte(&gb) & 0xE0;
164  tag = tag >> 5;
165 
166  if (tag == 0) {
167  if (writeoffset + 2 > hnm->width * hnm->height) {
168  av_log(avctx, AV_LOG_ERROR, "writeoffset out of bounds\n");
169  return AVERROR_INVALIDDATA;
170  }
171  hnm->current[writeoffset++] = bytestream2_get_byte(&gb);
172  hnm->current[writeoffset++] = bytestream2_get_byte(&gb);
173  } else if (tag == 1) {
174  writeoffset += bytestream2_get_byte(&gb) * 2;
175  } else if (tag == 2) {
176  count = bytestream2_get_le16(&gb);
177  count *= 2;
178  writeoffset += count;
179  } else if (tag == 3) {
180  count = bytestream2_get_byte(&gb) * 2;
181  if (writeoffset + count > hnm->width * hnm->height) {
182  av_log(avctx, AV_LOG_ERROR, "writeoffset out of bounds\n");
183  return AVERROR_INVALIDDATA;
184  }
185  while (count > 0) {
186  hnm->current[writeoffset++] = bytestream2_peek_byte(&gb);
187  count--;
188  }
189  bytestream2_skip(&gb, 1);
190  } else {
191  break;
192  }
193  if (writeoffset > hnm->width * hnm->height) {
194  av_log(avctx, AV_LOG_ERROR, "writeoffset out of bounds\n");
195  return AVERROR_INVALIDDATA;
196  }
197  } else {
198  previous = bytestream2_peek_byte(&gb) & 0x20;
199  backline = bytestream2_peek_byte(&gb) & 0x40;
200  backward = bytestream2_peek_byte(&gb) & 0x80;
201  bytestream2_skip(&gb, 1);
202  swap = bytestream2_peek_byte(&gb) & 0x01;
203  offset = bytestream2_get_le16(&gb);
204  offset = (offset >> 1) & 0x7FFF;
205  offset = writeoffset + (offset * 2) - 0x8000;
206 
207  left = count;
208 
209  if (!backward && offset + 2*count > hnm->width * hnm->height) {
210  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
211  return AVERROR_INVALIDDATA;
212  } else if (backward && offset + 1 >= hnm->width * hnm->height) {
213  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
214  return AVERROR_INVALIDDATA;
215  } else if (writeoffset + 2*count > hnm->width * hnm->height) {
216  av_log(avctx, AV_LOG_ERROR,
217  "Attempting to write out of bounds\n");
218  return AVERROR_INVALIDDATA;
219 
220  }
221  if(backward) {
222  if (offset < (!!backline)*(2 * hnm->width - 1) + 2*(left-1)) {
223  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
224  return AVERROR_INVALIDDATA;
225  }
226  } else {
227  if (offset < (!!backline)*(2 * hnm->width - 1)) {
228  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
229  return AVERROR_INVALIDDATA;
230  }
231  }
232 
233  if (previous) {
234  while (left > 0) {
235  if (backline) {
236  hnm->current[writeoffset++] = hnm->previous[offset - (2 * hnm->width) + 1];
237  hnm->current[writeoffset++] = hnm->previous[offset++];
238  offset++;
239  } else {
240  hnm->current[writeoffset++] = hnm->previous[offset++];
241  hnm->current[writeoffset++] = hnm->previous[offset++];
242  }
243  if (backward)
244  offset -= 4;
245  left--;
246  }
247  } else {
248  while (left > 0) {
249  if (backline) {
250  hnm->current[writeoffset++] = hnm->current[offset - (2 * hnm->width) + 1];
251  hnm->current[writeoffset++] = hnm->current[offset++];
252  offset++;
253  } else {
254  hnm->current[writeoffset++] = hnm->current[offset++];
255  hnm->current[writeoffset++] = hnm->current[offset++];
256  }
257  if (backward)
258  offset -= 4;
259  left--;
260  }
261  }
262 
263  if (swap) {
264  left = count;
265  writeoffset -= count * 2;
266  while (left > 0) {
267  swap = hnm->current[writeoffset];
268  hnm->current[writeoffset] = hnm->current[writeoffset + 1];
269  hnm->current[writeoffset + 1] = swap;
270  left--;
271  writeoffset += 2;
272  }
273  }
274  }
275  }
276  return 0;
277 }
278 
279 static void decode_interframe_v4a(AVCodecContext *avctx, const uint8_t *src,
280  uint32_t size)
281 {
282  Hnm4VideoContext *hnm = avctx->priv_data;
283  GetByteContext gb;
284  uint32_t writeoffset = 0, offset;
285  uint8_t tag, count, previous, delta;
286 
287  bytestream2_init(&gb, src, size);
288 
289  while (bytestream2_tell(&gb) < size) {
290  count = bytestream2_peek_byte(&gb) & 0x3F;
291  if (count == 0) {
292  tag = bytestream2_get_byte(&gb) & 0xC0;
293  tag = tag >> 6;
294  if (tag == 0) {
295  writeoffset += bytestream2_get_byte(&gb);
296  } else if (tag == 1) {
297  if (writeoffset + hnm->width >= hnm->width * hnm->height) {
298  av_log(avctx, AV_LOG_ERROR, "writeoffset out of bounds\n");
299  break;
300  }
301  hnm->current[writeoffset] = bytestream2_get_byte(&gb);
302  hnm->current[writeoffset + hnm->width] = bytestream2_get_byte(&gb);
303  writeoffset++;
304  } else if (tag == 2) {
305  writeoffset += hnm->width;
306  } else if (tag == 3) {
307  break;
308  }
309  if (writeoffset > hnm->width * hnm->height) {
310  av_log(avctx, AV_LOG_ERROR, "writeoffset out of bounds\n");
311  break;
312  }
313  } else {
314  delta = bytestream2_peek_byte(&gb) & 0x80;
315  previous = bytestream2_peek_byte(&gb) & 0x40;
316  bytestream2_skip(&gb, 1);
317 
318  offset = writeoffset;
319  offset += bytestream2_get_le16(&gb);
320 
321  if (delta) {
322  if (offset < 0x10000) {
323  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
324  break;
325  }
326  offset -= 0x10000;
327  }
328 
329  if (offset + hnm->width + count >= hnm->width * hnm->height) {
330  av_log(avctx, AV_LOG_ERROR, "Attempting to read out of bounds\n");
331  break;
332  } else if (writeoffset + hnm->width + count >= hnm->width * hnm->height) {
333  av_log(avctx, AV_LOG_ERROR, "Attempting to write out of bounds\n");
334  break;
335  }
336 
337  if (previous) {
338  while (count > 0) {
339  hnm->current[writeoffset] = hnm->previous[offset];
340  hnm->current[writeoffset + hnm->width] = hnm->previous[offset + hnm->width];
341  writeoffset++;
342  offset++;
343  count--;
344  }
345  } else {
346  while (count > 0) {
347  hnm->current[writeoffset] = hnm->current[offset];
348  hnm->current[writeoffset + hnm->width] = hnm->current[offset + hnm->width];
349  writeoffset++;
350  offset++;
351  count--;
352  }
353  }
354  }
355  }
356 }
357 
358 static void hnm_update_palette(AVCodecContext *avctx, const uint8_t *src,
359  uint32_t size)
360 {
361  Hnm4VideoContext *hnm = avctx->priv_data;
362  GetByteContext gb;
363  uint8_t start, writeoffset;
364  uint16_t count;
365  int eight_bit_colors;
366 
367  eight_bit_colors = src[7] & 0x80 && hnm->version == 0x4a;
368 
369  // skip first 8 bytes
370  bytestream2_init(&gb, src + 8, size - 8);
371 
372  while (bytestream2_tell(&gb) < size - 8) {
373  start = bytestream2_get_byte(&gb);
374  count = bytestream2_get_byte(&gb);
375  if (start == 255 && count == 255)
376  break;
377  if (count == 0)
378  count = 256;
379  writeoffset = start;
380  while (count > 0) {
381  hnm->palette[writeoffset] = bytestream2_get_be24(&gb);
382  if (!eight_bit_colors)
383  hnm->palette[writeoffset] <<= 2;
384  hnm->palette[writeoffset] |= (0xFFU << 24);
385  count--;
386  writeoffset++;
387  }
388  }
389 }
390 
392  int *got_frame, AVPacket *avpkt)
393 {
394  Hnm4VideoContext *hnm = avctx->priv_data;
395  int ret;
396  uint16_t chunk_id;
397 
398  if (avpkt->size < 8) {
399  av_log(avctx, AV_LOG_ERROR, "packet too small\n");
400  return AVERROR_INVALIDDATA;
401  }
402 
403  chunk_id = AV_RL16(avpkt->data + 4);
404 
405  if (chunk_id == HNM4_CHUNK_ID_PL) {
406  hnm_update_palette(avctx, avpkt->data, avpkt->size);
407  } else if (chunk_id == HNM4_CHUNK_ID_IZ) {
408  if (avpkt->size < 12) {
409  av_log(avctx, AV_LOG_ERROR, "packet too small\n");
410  return AVERROR_INVALIDDATA;
411  }
412  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
413  return ret;
414 
415  unpack_intraframe(avctx, avpkt->data + 12, avpkt->size - 12);
416  memcpy(hnm->previous, hnm->current, hnm->width * hnm->height);
417  if (hnm->version == 0x4a)
418  memcpy(hnm->processed, hnm->current, hnm->width * hnm->height);
419  else
421  copy_processed_frame(avctx, frame);
422  frame->pict_type = AV_PICTURE_TYPE_I;
423  frame->key_frame = 1;
424  memcpy(frame->data[1], hnm->palette, 256 * 4);
425  *got_frame = 1;
426  } else if (chunk_id == HNM4_CHUNK_ID_IU) {
427  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
428  return ret;
429 
430  if (hnm->version == 0x4a) {
431  decode_interframe_v4a(avctx, avpkt->data + 8, avpkt->size - 8);
432  memcpy(hnm->processed, hnm->current, hnm->width * hnm->height);
433  } else {
434  int ret = decode_interframe_v4(avctx, avpkt->data + 8, avpkt->size - 8);
435  if (ret < 0)
436  return ret;
438  }
439  copy_processed_frame(avctx, frame);
440  frame->pict_type = AV_PICTURE_TYPE_P;
441  frame->key_frame = 0;
442  memcpy(frame->data[1], hnm->palette, 256 * 4);
443  *got_frame = 1;
444  FFSWAP(uint8_t *, hnm->current, hnm->previous);
445  } else {
446  av_log(avctx, AV_LOG_ERROR, "invalid chunk id: %d\n", chunk_id);
447  return AVERROR_INVALIDDATA;
448  }
449 
450  return avpkt->size;
451 }
452 
454 {
455  Hnm4VideoContext *hnm = avctx->priv_data;
456  int ret;
457 
458  if (avctx->extradata_size < 1) {
459  av_log(avctx, AV_LOG_ERROR,
460  "Extradata missing, decoder requires version number\n");
461  return AVERROR_INVALIDDATA;
462  }
463 
464  ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
465  if (ret < 0)
466  return ret;
467  if (avctx->height & 1)
468  return AVERROR(EINVAL);
469 
470  hnm->version = avctx->extradata[0];
471  avctx->pix_fmt = AV_PIX_FMT_PAL8;
472  hnm->width = avctx->width;
473  hnm->height = avctx->height;
474  hnm->buffer1 = av_mallocz(avctx->width * avctx->height);
475  hnm->buffer2 = av_mallocz(avctx->width * avctx->height);
476  hnm->processed = av_mallocz(avctx->width * avctx->height);
477 
478  if (!hnm->buffer1 || !hnm->buffer2 || !hnm->processed) {
479  av_log(avctx, AV_LOG_ERROR, "av_mallocz() failed\n");
480  return AVERROR(ENOMEM);
481  }
482 
483  hnm->current = hnm->buffer1;
484  hnm->previous = hnm->buffer2;
485 
486  return 0;
487 }
488 
490 {
491  Hnm4VideoContext *hnm = avctx->priv_data;
492 
493  av_freep(&hnm->buffer1);
494  av_freep(&hnm->buffer2);
495  av_freep(&hnm->processed);
496 
497  return 0;
498 }
499 
501  .p.name = "hnm4video",
502  CODEC_LONG_NAME("HNM 4 video"),
503  .p.type = AVMEDIA_TYPE_VIDEO,
504  .p.id = AV_CODEC_ID_HNM4_VIDEO,
505  .priv_data_size = sizeof(Hnm4VideoContext),
507  .close = hnm_decode_end,
509  .p.capabilities = AV_CODEC_CAP_DR1,
510  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
511 };
copy_processed_frame
static void copy_processed_frame(AVCodecContext *avctx, AVFrame *frame)
Definition: hnm4video.c:136
HNM4_CHUNK_ID_IU
#define HNM4_CHUNK_ID_IU
Definition: hnm4video.c:36
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
AVERROR
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
GetByteContext
Definition: bytestream.h:33
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
AVPacket::data
uint8_t * data
Definition: packet.h:374
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uint8_t * buffer2
Definition: hnm4video.c:46
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uint8_t * processed
Definition: hnm4video.c:47
FFCodec
Definition: codec_internal.h:119
unpack_intraframe
static void unpack_intraframe(AVCodecContext *avctx, const uint8_t *src, uint32_t size)
Definition: hnm4video.c:67
HNM4_CHUNK_ID_PL
#define HNM4_CHUNK_ID_PL
Definition: hnm4video.c:34
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uint8_t version
Definition: hnm4video.c:40
ff_hnm4_video_decoder
const FFCodec ff_hnm4_video_decoder
Definition: hnm4video.c:500
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static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:168
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static void postprocess_current_frame(AVCodecContext *avctx)
Definition: hnm4video.c:118
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
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static av_cold int hnm_decode_end(AVCodecContext *avctx)
Definition: hnm4video.c:489
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
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int extradata_size
Definition: avcodec.h:500
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#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:298
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int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
bits
uint8_t bits
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AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
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#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
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uint8_t * buffer1
Definition: hnm4video.c:45
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uint8_t * current
Definition: hnm4video.c:43
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Definition: hnm4video.c:39
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
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Definition: avutil.h:274
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uint8_t * previous
Definition: hnm4video.c:44
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static av_always_inline int bytestream2_tell(GetByteContext *g)
Definition: bytestream.h:192
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int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1420
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#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
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int size
Definition: packet.h:375
codec_internal.h
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static void decode_interframe_v4a(AVCodecContext *avctx, const uint8_t *src, uint32_t size)
Definition: hnm4video.c:279
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int size
Definition: twinvq_data.h:10344
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static int getbit(GetByteContext *gb, uint32_t *bitbuf, int *bits)
Definition: hnm4video.c:51
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
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int width
Definition: hnm4video.c:41
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some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:499
internal.h
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#define HNM4_CHUNK_ID_IZ
Definition: hnm4video.c:35
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float delta
Definition: vorbis_enc_data.h:430
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@ AV_CODEC_ID_HNM4_VIDEO
Definition: codec_id.h:225
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:264
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
AVCodecContext::height
int height
Definition: avcodec.h:571
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:608
avcodec.h
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
tag
uint32_t tag
Definition: movenc.c:1647
ret
ret
Definition: filter_design.txt:187
FFSWAP
#define FFSWAP(type, a, b)
Definition: macros.h:52
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
left
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:386
U
#define U(x)
Definition: vpx_arith.h:37
AVCodecContext
main external API structure.
Definition: avcodec.h:398
hnm_decode_frame
static int hnm_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
Definition: hnm4video.c:391
decode_interframe_v4
static int decode_interframe_v4(AVCodecContext *avctx, const uint8_t *src, uint32_t size)
Definition: hnm4video.c:150
Hnm4VideoContext::height
int height
Definition: hnm4video.c:42
Hnm4VideoContext::palette
uint32_t palette[256]
Definition: hnm4video.c:48
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
hnm_decode_init
static av_cold int hnm_decode_init(AVCodecContext *avctx)
Definition: hnm4video.c:453
mem.h
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:425
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:571
int32_t
int32_t
Definition: audioconvert.c:56
bytestream.h
imgutils.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
av_image_check_size
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:318
hnm_update_palette
static void hnm_update_palette(AVCodecContext *avctx, const uint8_t *src, uint32_t size)
Definition: hnm4video.c:358