vble.c
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1 /*
2  * VBLE Decoder
3  * Copyright (c) 2011 Derek Buitenhuis
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #define BITSTREAM_READER_LE
28 
29 #include "avcodec.h"
30 #include "dsputil.h"
31 #include "get_bits.h"
32 #include "internal.h"
33 #include "mathops.h"
34 
35 typedef struct {
38 
39  int size;
40  uint8_t *val; /* First holds the lengths of vlc symbols and then their values */
41 } VBLEContext;
42 
44 {
45  /* At most we need to read 9 bits total to get indices up to 8 */
46  uint8_t val = show_bits(gb, 8);
47 
48  if (val) {
49  val = 7 - av_log2_16bit(ff_reverse[val]);
50  skip_bits(gb, val + 1);
51  return val;
52  } else {
53  skip_bits(gb, 8);
54  if (get_bits1(gb))
55  return 8;
56  }
57 
58  /* Return something larger than 8 on error */
59  return UINT8_MAX;
60 }
61 
62 static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
63 {
64  int i;
65 
66  /* Read all the lengths in first */
67  for (i = 0; i < ctx->size; i++) {
68  ctx->val[i] = vble_read_reverse_unary(gb);
69 
70  if (ctx->val[i] == UINT8_MAX)
71  return -1;
72  }
73 
74  for (i = 0; i < ctx->size; i++) {
75  /* Check we have enough bits left */
76  if (get_bits_left(gb) < ctx->val[i])
77  return -1;
78 
79  /* get_bits can't take a length of 0 */
80  if (ctx->val[i])
81  ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1;
82  }
83 
84  return 0;
85 }
86 
87 static void vble_restore_plane(VBLEContext *ctx, int plane, int offset,
88  int width, int height)
89 {
90  AVFrame *pic = ctx->avctx->coded_frame;
91  uint8_t *dst = pic->data[plane];
92  uint8_t *val = ctx->val + offset;
93  int stride = pic->linesize[plane];
94  int i, j, left, left_top;
95 
96  for (i = 0; i < height; i++) {
97  for (j = 0; j < width; j++)
98  val[j] = (val[j] >> 1) ^ -(val[j] & 1);
99 
100  if (i) {
101  left = 0;
102  left_top = dst[-stride];
103  ctx->dsp.add_hfyu_median_prediction(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 = avctx->coded_frame;
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 
126  pic->reference = 0;
127 
128  /* Clear buffer if need be */
129  if (pic->data[0])
130  avctx->release_buffer(avctx, pic);
131 
132  /* Allocate buffer */
133  if (ff_get_buffer(avctx, pic) < 0) {
134  av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
135  return AVERROR(ENOMEM);
136  }
137 
138  /* Set flags */
139  pic->key_frame = 1;
141 
142  /* Version should always be 1 */
143  version = AV_RL32(src);
144 
145  if (version != 1)
146  av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
147 
148  init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
149 
150  /* Unpack */
151  if (vble_unpack(ctx, &gb) < 0) {
152  av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
153  return AVERROR_INVALIDDATA;
154  }
155 
156  /* Restore planes. Should be almost identical to Huffyuv's. */
157  vble_restore_plane(ctx, 0, offset, avctx->width, avctx->height);
158 
159  /* Chroma */
160  if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
161  offset += avctx->width * avctx->height;
162  vble_restore_plane(ctx, 1, offset, width_uv, height_uv);
163 
164  offset += width_uv * height_uv;
165  vble_restore_plane(ctx, 2, offset, width_uv, height_uv);
166  }
167 
168  *got_frame = 1;
169  *(AVFrame *)data = *pic;
170 
171  return avpkt->size;
172 }
173 
175 {
176  VBLEContext *ctx = avctx->priv_data;
177  AVFrame *pic = avctx->coded_frame;
178 
179  if (pic->data[0])
180  avctx->release_buffer(avctx, pic);
181 
182  av_freep(&avctx->coded_frame);
183  av_freep(&ctx->val);
184 
185  return 0;
186 }
187 
189 {
190  VBLEContext *ctx = avctx->priv_data;
191 
192  /* Stash for later use */
193  ctx->avctx = avctx;
194  ff_dsputil_init(&ctx->dsp, avctx);
195 
196  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
197  avctx->bits_per_raw_sample = 8;
198  avctx->coded_frame = avcodec_alloc_frame();
199 
200  if (!avctx->coded_frame) {
201  av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
202  return AVERROR(ENOMEM);
203  }
204 
205  ctx->size = avpicture_get_size(avctx->pix_fmt,
206  avctx->width, avctx->height);
207 
208  ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
209 
210  if (!ctx->val) {
211  av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
212  vble_decode_close(avctx);
213  return AVERROR(ENOMEM);
214  }
215 
216  return 0;
217 }
218 
220  .name = "vble",
221  .type = AVMEDIA_TYPE_VIDEO,
222  .id = AV_CODEC_ID_VBLE,
223  .priv_data_size = sizeof(VBLEContext),
227  .capabilities = CODEC_CAP_DR1,
228  .long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
229 };