FFmpeg: libavcodec/vble.c Source File

FFmpeg
vble.c
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1 /*
2  * VBLE Decoder
3  * Copyright (c) 2011 Derek Buitenhuis
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  * VBLE Decoder
25  */
26 
27  #define BITSTREAM_READER_LE
28 
29 #include "avcodec.h"
30 #include "get_bits.h"
31 #include "huffyuvdsp.h"
32 #include "internal.h"
33 #include "mathops.h"
34 
35  typedef struct VBLEContext {
36   AVCodecContext *avctx;
37   HuffYUVDSPContext hdsp;
38 
39   int size;
40   uint8_t *val; ///< This array first holds the lengths of vlc symbols and then their value.
41 } VBLEContext;
42 
43  static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
44 {
45  int i;
46  int allbits = 0;
47  static const uint8_t LUT[256] = {
48  8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
49  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
50  6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
51  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
52  7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
53  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
54  6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
55  5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
56  };
57 
58  /* Read all the lengths in first */
59  for (i = 0; i < ctx->size; i++) {
60  /* At most we need to read 9 bits total to get indices up to 8 */
61  int val = show_bits(gb, 8);
62 
63  // read reverse unary
64  if (val) {
65  val = LUT[val];
66  skip_bits(gb, val + 1);
67  ctx->val[i] = val;
68  } else {
69  skip_bits(gb, 8);
70  if (!get_bits1(gb))
71  return -1;
72  ctx->val[i] = 8;
73  }
74  allbits += ctx->val[i];
75  }
76 
77  /* Check we have enough bits left */
78  if (get_bits_left(gb) < allbits)
79  return -1;
80  return 0;
81 }
82 
83  static void vble_restore_plane(VBLEContext *ctx, AVFrame *pic,
84  GetBitContext *gb, int plane,
85  int offset, int width, int height)
86 {
87  uint8_t *dst = pic->data[plane];
88  uint8_t *val = ctx->val + offset;
89  int stride = pic->linesize[plane];
90  int i, j, left, left_top;
91 
92  for (i = 0; i < height; i++) {
93  for (j = 0; j < width; j++) {
94  /* get_bits can't take a length of 0 */
95  if (val[j]) {
96  int v = (1 << val[j]) + get_bits(gb, val[j]) - 1;
97  val[j] = (v >> 1) ^ -(v & 1);
98  }
99  }
100  if (i) {
101  left = 0;
102  left_top = dst[-stride];
103  ctx->hdsp.add_hfyu_median_pred(dst, dst - stride, val,
104  width, &left, &left_top);
105  } else {
106  dst[0] = val[0];
107  for (j = 1; j < width; j++)
108  dst[j] = val[j] + dst[j - 1];
109  }
110  dst += stride;
111  val += width;
112  }
113 }
114 
115  static int vble_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
116  AVPacket *avpkt)
117 {
118  VBLEContext *ctx = avctx->priv_data;
119  AVFrame *pic = data;
120  GetBitContext gb;
121  const uint8_t *src = avpkt->data;
122  int version;
123  int offset = 0;
124  int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
125  int ret;
126 
127  if (avpkt->size < 4 || avpkt->size - 4 > INT_MAX/8) {
128  av_log(avctx, AV_LOG_ERROR, "Invalid packet size\n");
129  return AVERROR_INVALIDDATA;
130  }
131 
132  /* Allocate buffer */
133  if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
134  return ret;
135 
136  /* Set flags */
137  pic->key_frame = 1;
138  pic->pict_type = AV_PICTURE_TYPE_I;
139 
140  /* Version should always be 1 */
141  version = AV_RL32(src);
142 
143  if (version != 1)
144  av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
145 
146  init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
147 
148  /* Unpack */
149  if (vble_unpack(ctx, &gb) < 0) {
150  av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
151  return AVERROR_INVALIDDATA;
152  }
153 
154  /* Restore planes. Should be almost identical to Huffyuv's. */
155  vble_restore_plane(ctx, pic, &gb, 0, offset, avctx->width, avctx->height);
156 
157  /* Chroma */
158  if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
159  offset += avctx->width * avctx->height;
160  vble_restore_plane(ctx, pic, &gb, 1, offset, width_uv, height_uv);
161 
162  offset += width_uv * height_uv;
163  vble_restore_plane(ctx, pic, &gb, 2, offset, width_uv, height_uv);
164  }
165 
166  *got_frame = 1;
167 
168  return avpkt->size;
169 }
170 
171  static av_cold int vble_decode_close(AVCodecContext *avctx)
172 {
173  VBLEContext *ctx = avctx->priv_data;
174  av_freep(&ctx->val);
175 
176  return 0;
177 }
178 
179  static av_cold int vble_decode_init(AVCodecContext *avctx)
180 {
181  VBLEContext *ctx = avctx->priv_data;
182 
183  /* Stash for later use */
184  ctx->avctx = avctx;
185  ff_huffyuvdsp_init(&ctx->hdsp);
186 
187  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
188  avctx->bits_per_raw_sample = 8;
189 
190  ctx->size = avpicture_get_size(avctx->pix_fmt,
191  avctx->width, avctx->height);
192 
193  ctx->val = av_malloc_array(ctx->size, sizeof(*ctx->val));
194 
195  if (!ctx->val) {
196  av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
197  vble_decode_close(avctx);
198  return AVERROR(ENOMEM);
199  }
200 
201  return 0;
202 }
203 
204  AVCodec ff_vble_decoder = {
205  .name = "vble",
206  .long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
207  .type = AVMEDIA_TYPE_VIDEO,
208  .id = AV_CODEC_ID_VBLE,
209  .priv_data_size = sizeof(VBLEContext),
210  .init = vble_decode_init,
211  .close = vble_decode_close,
212  .decode = vble_decode_frame,
213  .capabilities = CODEC_CAP_DR1,
214 };
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