FFmpeg: libavcodec/jvdec.c Source File

FFmpeg
jvdec.c
Go to the documentation of this file.
1 /*
2  * Bitmap Brothers JV video decoder
3  * Copyright (c) 2011 Peter Ross <pross@xvid.org>
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  * Bitmap Brothers JV video decoder
25  * @author Peter Ross <pross@xvid.org>
26  */
27 
28 #include "avcodec.h"
29 #include "dsputil.h"
30 #include "get_bits.h"
31 #include "internal.h"
32 #include "libavutil/intreadwrite.h"
33 
34  typedef struct JvContext {
35   DSPContext dsp;
36   AVFrame *frame;
37   uint32_t palette[AVPALETTE_COUNT];
38   int palette_has_changed;
39 } JvContext;
40 
41  static av_cold int decode_init(AVCodecContext *avctx)
42 {
43  JvContext *s = avctx->priv_data;
44 
45  s->frame = av_frame_alloc();
46  if (!s->frame)
47  return AVERROR(ENOMEM);
48 
49  avctx->pix_fmt = AV_PIX_FMT_PAL8;
50  ff_dsputil_init(&s->dsp, avctx);
51  return 0;
52 }
53 
54 /**
55  * Decode 2x2 block
56  */
57  static inline void decode2x2(GetBitContext *gb, uint8_t *dst, int linesize)
58 {
59  int i, j, v[2];
60 
61  switch (get_bits(gb, 2)) {
62  case 1:
63  v[0] = get_bits(gb, 8);
64  for (j = 0; j < 2; j++)
65  memset(dst + j*linesize, v[0], 2);
66  break;
67  case 2:
68  v[0] = get_bits(gb, 8);
69  v[1] = get_bits(gb, 8);
70  for (j = 0; j < 2; j++)
71  for (i = 0; i < 2; i++)
72  dst[j*linesize + i] = v[get_bits1(gb)];
73  break;
74  case 3:
75  for (j = 0; j < 2; j++)
76  for (i = 0; i < 2; i++)
77  dst[j*linesize + i] = get_bits(gb, 8);
78  }
79 }
80 
81 /**
82  * Decode 4x4 block
83  */
84  static inline void decode4x4(GetBitContext *gb, uint8_t *dst, int linesize)
85 {
86  int i, j, v[2];
87 
88  switch (get_bits(gb, 2)) {
89  case 1:
90  v[0] = get_bits(gb, 8);
91  for (j = 0; j < 4; j++)
92  memset(dst + j*linesize, v[0], 4);
93  break;
94  case 2:
95  v[0] = get_bits(gb, 8);
96  v[1] = get_bits(gb, 8);
97  for (j = 2; j >= 0; j -= 2) {
98  for (i = 0; i < 4; i++)
99  dst[j*linesize + i] = v[get_bits1(gb)];
100  for (i = 0; i < 4; i++)
101  dst[(j+1)*linesize + i] = v[get_bits1(gb)];
102  }
103  break;
104  case 3:
105  for (j = 0; j < 4; j += 2)
106  for (i = 0; i < 4; i += 2)
107  decode2x2(gb, dst + j*linesize + i, linesize);
108  }
109 }
110 
111 /**
112  * Decode 8x8 block
113  */
114  static inline void decode8x8(GetBitContext *gb, uint8_t *dst, int linesize, DSPContext *dsp)
115 {
116  int i, j, v[2];
117 
118  switch (get_bits(gb, 2)) {
119  case 1:
120  v[0] = get_bits(gb, 8);
121  dsp->fill_block_tab[1](dst, v[0], linesize, 8);
122  break;
123  case 2:
124  v[0] = get_bits(gb, 8);
125  v[1] = get_bits(gb, 8);
126  for (j = 7; j >= 0; j--)
127  for (i = 0; i < 8; i++)
128  dst[j*linesize + i] = v[get_bits1(gb)];
129  break;
130  case 3:
131  for (j = 0; j < 8; j += 4)
132  for (i = 0; i < 8; i += 4)
133  decode4x4(gb, dst + j*linesize + i, linesize);
134  }
135 }
136 
137  static int decode_frame(AVCodecContext *avctx,
138  void *data, int *got_frame,
139  AVPacket *avpkt)
140 {
141  JvContext *s = avctx->priv_data;
142  const uint8_t *buf = avpkt->data;
143  const uint8_t *buf_end = buf + avpkt->size;
144  int video_size, video_type, i, j, ret;
145 
146  if (avpkt->size < 6)
147  return AVERROR_INVALIDDATA;
148 
149  video_size = AV_RL32(buf);
150  video_type = buf[4];
151  buf += 5;
152 
153  if (video_size) {
154  if (video_size < 0 || video_size > avpkt->size - 5) {
155  av_log(avctx, AV_LOG_ERROR, "video size %d invalid\n", video_size);
156  return AVERROR_INVALIDDATA;
157  }
158  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
159  return ret;
160 
161  if (video_type == 0 || video_type == 1) {
162  GetBitContext gb;
163  init_get_bits(&gb, buf, 8 * video_size);
164 
165  for (j = 0; j < avctx->height; j += 8)
166  for (i = 0; i < avctx->width; i += 8)
167  decode8x8(&gb, s->frame->data[0] + j * s->frame->linesize[0] + i,
168  s->frame->linesize[0], &s->dsp);
169 
170  buf += video_size;
171  } else if (video_type == 2) {
172  int v = *buf++;
173  for (j = 0; j < avctx->height; j++)
174  memset(s->frame->data[0] + j * s->frame->linesize[0], v, avctx->width);
175  } else {
176  av_log(avctx, AV_LOG_WARNING, "unsupported frame type %i\n", video_type);
177  return AVERROR_INVALIDDATA;
178  }
179  }
180 
181  if (buf_end - buf >= AVPALETTE_COUNT * 3) {
182  for (i = 0; i < AVPALETTE_COUNT; i++) {
183  uint32_t pal = AV_RB24(buf);
184  s->palette[i] = 0xFFU << 24 | pal << 2 | ((pal >> 4) & 0x30303);
185  buf += 3;
186  }
187  s->palette_has_changed = 1;
188  }
189 
190  if (video_size) {
191  s->frame->key_frame = 1;
192  s->frame->pict_type = AV_PICTURE_TYPE_I;
193  s->frame->palette_has_changed = s->palette_has_changed;
194  s->palette_has_changed = 0;
195  memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
196 
197  if ((ret = av_frame_ref(data, s->frame)) < 0)
198  return ret;
199  *got_frame = 1;
200  }
201 
202  return avpkt->size;
203 }
204 
205  static av_cold int decode_close(AVCodecContext *avctx)
206 {
207  JvContext *s = avctx->priv_data;
208 
209  av_frame_free(&s->frame);
210 
211  return 0;
212 }
213 
214  AVCodec ff_jv_decoder = {
215  .name = "jv",
216  .long_name = NULL_IF_CONFIG_SMALL("Bitmap Brothers JV video"),
217  .type = AVMEDIA_TYPE_VIDEO,
218  .id = AV_CODEC_ID_JV,
219  .priv_data_size = sizeof(JvContext),
220  .init = decode_init,
221  .close = decode_close,
222  .decode = decode_frame,
223  .capabilities = CODEC_CAP_DR1,
224 };
Generated on Sat Jan 25 2014 19:51:50 for FFmpeg by   doxygen 1.8.2

AltStyle によって変換されたページ (->オリジナル) /