FFmpeg
mvha.c
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1 /*
2  * MidiVid Archive codec
3  *
4  * Copyright (c) 2019 Paul B Mahol
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 #define CACHED_BITSTREAM_READER !ARCH_X86_32
24 #include "libavutil/intreadwrite.h"
25 
26 #include "avcodec.h"
27 #include "codec_internal.h"
28 #include "decode.h"
29 #include "get_bits.h"
30 #include "lossless_videodsp.h"
31 #include "zlib_wrapper.h"
32 
33 #include <zlib.h>
34 
35 typedef struct MVHAContext {
38 
39  uint8_t symb[256];
40  uint32_t prob[256];
42 
45 } MVHAContext;
46 
47 typedef struct Node {
48  int16_t sym;
49  int16_t n0;
50  int16_t l, r;
51  uint32_t count;
52 } Node;
53 
54 static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat,
55  Node *nodes, int node,
56  uint32_t pfx, int pl, int *pos)
57 {
58  int s;
59 
60  s = nodes[node].sym;
61  if (s != -1) {
62  bits[*pos] = (~pfx) & ((1ULL << FFMAX(pl, 1)) - 1);
63  lens[*pos] = FFMAX(pl, 1);
64  xlat[*pos] = s + (pl == 0);
65  (*pos)++;
66  } else {
67  pfx <<= 1;
68  pl++;
69  get_tree_codes(bits, lens, xlat, nodes, nodes[node].l, pfx, pl,
70  pos);
71  pfx |= 1;
72  get_tree_codes(bits, lens, xlat, nodes, nodes[node].r, pfx, pl,
73  pos);
74  }
75 }
76 
77 static int build_vlc(AVCodecContext *avctx, VLC *vlc)
78 {
79  MVHAContext *s = avctx->priv_data;
80  Node nodes[512];
81  uint32_t bits[256];
82  int16_t lens[256];
83  uint8_t xlat[256];
84  int cur_node, i, j, pos = 0;
85 
86  ff_free_vlc(vlc);
87 
88  for (i = 0; i < s->nb_symbols; i++) {
89  nodes[i].count = s->prob[i];
90  nodes[i].sym = s->symb[i];
91  nodes[i].n0 = -2;
92  nodes[i].l = i;
93  nodes[i].r = i;
94  }
95 
96  cur_node = s->nb_symbols;
97  j = 0;
98  do {
99  for (i = 0; ; i++) {
100  int new_node = j;
101  int first_node = cur_node;
102  int second_node = cur_node;
103  unsigned nd, st;
104 
105  nodes[cur_node].count = -1;
106 
107  do {
108  int val = nodes[new_node].count;
109  if (val && (val < nodes[first_node].count)) {
110  if (val >= nodes[second_node].count) {
111  first_node = new_node;
112  } else {
113  first_node = second_node;
114  second_node = new_node;
115  }
116  }
117  new_node += 1;
118  } while (new_node != cur_node);
119 
120  if (first_node == cur_node)
121  break;
122 
123  nd = nodes[second_node].count;
124  st = nodes[first_node].count;
125  nodes[second_node].count = 0;
126  nodes[first_node].count = 0;
127  if (nd >= UINT32_MAX - st) {
128  av_log(avctx, AV_LOG_ERROR, "count overflow\n");
129  return AVERROR_INVALIDDATA;
130  }
131  nodes[cur_node].count = nd + st;
132  nodes[cur_node].sym = -1;
133  nodes[cur_node].n0 = cur_node;
134  nodes[cur_node].l = first_node;
135  nodes[cur_node].r = second_node;
136  cur_node++;
137  }
138  j++;
139  } while (cur_node - s->nb_symbols == j);
140 
141  get_tree_codes(bits, lens, xlat, nodes, cur_node - 1, 0, 0, &pos);
142 
143  return ff_init_vlc_sparse(vlc, 12, pos, lens, 2, 2, bits, 4, 4, xlat, 1, 1, 0);
144 }
145 
147  int *got_frame, AVPacket *avpkt)
148 {
149  MVHAContext *s = avctx->priv_data;
150  uint32_t type, size;
151  int ret;
152 
153  if (avpkt->size <= 8)
154  return AVERROR_INVALIDDATA;
155 
156  type = AV_RB32(avpkt->data);
157  size = AV_RL32(avpkt->data + 4);
158 
159  if (size < 1 || size >= avpkt->size)
160  return AVERROR_INVALIDDATA;
161 
162  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
163  return ret;
164 
165  if (type == MKTAG('L','Z','Y','V')) {
166  z_stream *const zstream = &s->zstream.zstream;
167  ret = inflateReset(zstream);
168  if (ret != Z_OK) {
169  av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
170  return AVERROR_EXTERNAL;
171  }
172 
173  zstream->next_in = avpkt->data + 8;
174  zstream->avail_in = avpkt->size - 8;
175 
176  for (int p = 0; p < 3; p++) {
177  for (int y = 0; y < avctx->height; y++) {
178  zstream->next_out = frame->data[p] + (avctx->height - y - 1) * frame->linesize[p];
179  zstream->avail_out = avctx->width >> (p > 0);
180 
181  ret = inflate(zstream, Z_SYNC_FLUSH);
182  if (ret != Z_OK && ret != Z_STREAM_END) {
183  av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
184  return AVERROR_EXTERNAL;
185  }
186  }
187  }
188  } else if (type == MKTAG('H','U','F','Y')) {
189  GetBitContext *gb = &s->gb;
190  int first_symbol, symbol;
191 
192  ret = init_get_bits8(gb, avpkt->data + 8, avpkt->size - 8);
193  if (ret < 0)
194  return ret;
195 
196  skip_bits(gb, 24);
197 
198  first_symbol = get_bits(gb, 8);
199  s->nb_symbols = get_bits(gb, 8) + 1;
200 
201  symbol = first_symbol;
202  for (int i = 0; i < s->nb_symbols; symbol++) {
203  int prob;
204 
205  if (get_bits_left(gb) < 4)
206  return AVERROR_INVALIDDATA;
207 
208  if (get_bits1(gb)) {
209  prob = get_bits(gb, 12);
210  } else {
211  prob = get_bits(gb, 3);
212  }
213 
214  if (prob) {
215  s->symb[i] = symbol;
216  s->prob[i] = prob;
217  i++;
218  }
219  }
220 
221  ret = build_vlc(avctx, &s->vlc);
222  if (ret < 0)
223  return ret;
224 
225  for (int p = 0; p < 3; p++) {
226  int width = avctx->width >> (p > 0);
227  ptrdiff_t stride = frame->linesize[p];
228  uint8_t *dst;
229 
230  dst = frame->data[p] + (avctx->height - 1) * frame->linesize[p];
231  for (int y = 0; y < avctx->height; y++) {
232  if (get_bits_left(gb) < width)
233  return AVERROR_INVALIDDATA;
234  for (int x = 0; x < width; x++) {
235  int v = get_vlc2(gb, s->vlc.table, s->vlc.bits, 3);
236 
237  if (v < 0)
238  return AVERROR_INVALIDDATA;
239 
240  dst[x] = v;
241  }
242  dst -= stride;
243  }
244  }
245  } else {
246  return AVERROR_INVALIDDATA;
247  }
248 
249  for (int p = 0; p < 3; p++) {
250  int left, lefttop;
251  int width = avctx->width >> (p > 0);
252  ptrdiff_t stride = frame->linesize[p];
253  uint8_t *dst;
254 
255  dst = frame->data[p] + (avctx->height - 1) * frame->linesize[p];
256  s->llviddsp.add_left_pred(dst, dst, width, 0);
257  if (avctx->height > 1) {
258  dst -= stride;
259  lefttop = left = dst[0];
260  for (int y = 1; y < avctx->height; y++) {
261  s->llviddsp.add_median_pred(dst, dst + stride, dst, width, &left, &lefttop);
262  lefttop = left = dst[0];
263  dst -= stride;
264  }
265  }
266  }
267 
268  frame->pict_type = AV_PICTURE_TYPE_I;
269  frame->key_frame = 1;
270  *got_frame = 1;
271 
272  return avpkt->size;
273 }
274 
276 {
277  MVHAContext *s = avctx->priv_data;
278 
279  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
280 
281  ff_llviddsp_init(&s->llviddsp);
282 
283  return ff_inflate_init(&s->zstream, avctx);
284 }
285 
287 {
288  MVHAContext *s = avctx->priv_data;
289 
290  ff_inflate_end(&s->zstream);
291  ff_free_vlc(&s->vlc);
292 
293  return 0;
294 }
295 
297  .p.name = "mvha",
298  CODEC_LONG_NAME("MidiVid Archive Codec"),
299  .p.type = AVMEDIA_TYPE_VIDEO,
300  .p.id = AV_CODEC_ID_MVHA,
301  .priv_data_size = sizeof(MVHAContext),
302  .init = decode_init,
303  .close = decode_close,
305  .p.capabilities = AV_CODEC_CAP_DR1,
306  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
307 };
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
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:839
r
const char * r
Definition: vf_curves.c:126
MVHAContext::symb
uint8_t symb[256]
Definition: mvha.c:39
decode_close
static av_cold int decode_close(AVCodecContext *avctx)
Definition: mvha.c:286
Node
Definition: agm.c:897
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
MVHAContext::prob
uint32_t prob[256]
Definition: mvha.c:40
AVPacket::data
uint8_t * data
Definition: packet.h:374
FFCodec
Definition: codec_internal.h:119
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
inflate
static void inflate(uint8_t *dst, const uint8_t *p1, int width, int threshold, const uint8_t *coordinates[], int coord, int maxc)
Definition: vf_neighbor.c:195
GetBitContext
Definition: get_bits.h:61
val
static double val(void *priv, double ch)
Definition: aeval.c:77
type
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 type
Definition: writing_filters.txt:86
LLVidDSPContext
Definition: lossless_videodsp.h:28
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
zlib_wrapper.h
av_cold
#define av_cold
Definition: attributes.h:90
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:667
width
#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:298
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
MVHAContext::nb_symbols
int nb_symbols
Definition: mvha.c:37
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
bits
uint8_t bits
Definition: vp3data.h:128
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: mvha.c:275
decode.h
get_bits.h
ff_mvha_decoder
const FFCodec ff_mvha_decoder
Definition: mvha.c:296
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
Node::l
int16_t l
Definition: mvha.c:50
get_vlc2
static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, int bits, int max_depth)
Parse a vlc code.
Definition: get_bits.h:787
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1450
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:375
MVHAContext::llviddsp
LLVidDSPContext llviddsp
Definition: mvha.c:44
codec_internal.h
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
size
int size
Definition: twinvq_data.h:10344
AV_RB32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:96
MVHAContext::gb
GetBitContext gb
Definition: mvha.c:36
AVERROR_EXTERNAL
#define AVERROR_EXTERNAL
Generic error in an external library.
Definition: error.h:59
Node::r
int16_t r
Definition: mvha.c:50
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
ff_init_vlc_sparse
int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, const void *symbols, int symbols_wrap, int symbols_size, int flags)
Definition: vlc.c:272
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
ff_inflate_end
void ff_inflate_end(FFZStream *zstream)
Wrapper around inflateEnd().
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
AV_CODEC_ID_MVHA
@ AV_CODEC_ID_MVHA
Definition: codec_id.h:302
ff_free_vlc
void ff_free_vlc(VLC *vlc)
Definition: vlc.c:375
avcodec.h
stride
#define stride
Definition: h264pred_template.c:537
MVHAContext::zstream
FFZStream zstream
Definition: mvha.c:43
ret
ret
Definition: filter_design.txt:187
MVHAContext::vlc
VLC vlc
Definition: mvha.c:41
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
prob
#define prob(name, subs,...)
Definition: cbs_vp9.c:372
Node::n0
int16_t n0
Definition: huffman.h:35
pos
unsigned int pos
Definition: spdifenc.c:412
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
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
ff_llviddsp_init
void ff_llviddsp_init(LLVidDSPContext *c)
Definition: lossless_videodsp.c:113
AVCodecContext
main external API structure.
Definition: avcodec.h:398
VLC
Definition: vlc.h:31
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
FFZStream
Definition: zlib_wrapper.h:27
AV_PIX_FMT_YUV422P
@ AV_PIX_FMT_YUV422P
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
Node::sym
int16_t sym
Definition: huffman.h:34
get_tree_codes
static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, Node *nodes, int node, uint32_t pfx, int pl, int *pos)
Definition: mvha.c:54
lossless_videodsp.h
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
Definition: mvha.c:146
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:425
ff_inflate_init
int ff_inflate_init(FFZStream *zstream, void *logctx)
Wrapper around inflateInit().
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:571
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
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
Node::count
uint32_t count
Definition: huffman.h:36
build_vlc
static int build_vlc(AVCodecContext *avctx, VLC *vlc)
Definition: mvha.c:77
MVHAContext
Definition: mvha.c:35