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rpza.c
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1 /*
2  * Quicktime Video (RPZA) Video Decoder
3  * Copyright (C) 2003 the ffmpeg project
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  * QT RPZA Video Decoder by Roberto Togni
25  * For more information about the RPZA format, visit:
26  * http://www.pcisys.net/~melanson/codecs/
27  *
28  * The RPZA decoder outputs RGB555 colorspace data.
29  *
30  * Note that this decoder reads big endian RGB555 pixel values from the
31  * bytestream, arranges them in the host's endian order, and outputs
32  * them to the final rendered map in the same host endian order. This is
33  * intended behavior as the libavcodec documentation states that RGB555
34  * pixels shall be stored in native CPU endianness.
35  */
36 
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 
41 #include "libavutil/internal.h"
42 #include "libavutil/intreadwrite.h"
43 #include "avcodec.h"
44 
45 typedef struct RpzaContext {
46 
49 
50  const unsigned char *buf;
51  int size;
52 
53 } RpzaContext;
54 
55 #define ADVANCE_BLOCK() \
56 { \
57  pixel_ptr += 4; \
58  if (pixel_ptr >= width) \
59  { \
60  pixel_ptr = 0; \
61  row_ptr += stride * 4; \
62  } \
63  total_blocks--; \
64  if (total_blocks < 0) \
65  { \
66  av_log(s->avctx, AV_LOG_ERROR, "warning: block counter just went negative (this should not happen)\n"); \
67  return; \
68  } \
69 }
70 
72 {
73  int width = s->avctx->width;
74  int stride = s->frame.linesize[0] / 2;
75  int row_inc = stride - 4;
76  int stream_ptr = 0;
77  int chunk_size;
78  unsigned char opcode;
79  int n_blocks;
80  unsigned short colorA = 0, colorB;
81  unsigned short color4[4];
82  unsigned char index, idx;
83  unsigned short ta, tb;
84  unsigned short *pixels = (unsigned short *)s->frame.data[0];
85 
86  int row_ptr = 0;
87  int pixel_ptr = 0;
88  int block_ptr;
89  int pixel_x, pixel_y;
90  int total_blocks;
91 
92  /* First byte is always 0xe1. Warn if it's different */
93  if (s->buf[stream_ptr] != 0xe1)
94  av_log(s->avctx, AV_LOG_ERROR, "First chunk byte is 0x%02x instead of 0xe1\n",
95  s->buf[stream_ptr]);
96 
97  /* Get chunk size, ingnoring first byte */
98  chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
99  stream_ptr += 4;
100 
101  /* If length mismatch use size from MOV file and try to decode anyway */
102  if (chunk_size != s->size)
103  av_log(s->avctx, AV_LOG_ERROR, "MOV chunk size != encoded chunk size; using MOV chunk size\n");
104 
105  chunk_size = s->size;
106 
107  /* Number of 4x4 blocks in frame. */
108  total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
109 
110  /* Process chunk data */
111  while (stream_ptr < chunk_size) {
112  opcode = s->buf[stream_ptr++]; /* Get opcode */
113 
114  n_blocks = (opcode & 0x1f) + 1; /* Extract block counter from opcode */
115 
116  /* If opcode MSbit is 0, we need more data to decide what to do */
117  if ((opcode & 0x80) == 0) {
118  colorA = (opcode << 8) | (s->buf[stream_ptr++]);
119  opcode = 0;
120  if ((s->buf[stream_ptr] & 0x80) != 0) {
121  /* Must behave as opcode 110xxxxx, using colorA computed
122  * above. Use fake opcode 0x20 to enter switch block at
123  * the right place */
124  opcode = 0x20;
125  n_blocks = 1;
126  }
127  }
128 
129  switch (opcode & 0xe0) {
130 
131  /* Skip blocks */
132  case 0x80:
133  while (n_blocks--) {
134  ADVANCE_BLOCK();
135  }
136  break;
137 
138  /* Fill blocks with one color */
139  case 0xa0:
140  colorA = AV_RB16 (&s->buf[stream_ptr]);
141  stream_ptr += 2;
142  while (n_blocks--) {
143  block_ptr = row_ptr + pixel_ptr;
144  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
145  for (pixel_x = 0; pixel_x < 4; pixel_x++){
146  pixels[block_ptr] = colorA;
147  block_ptr++;
148  }
149  block_ptr += row_inc;
150  }
151  ADVANCE_BLOCK();
152  }
153  break;
154 
155  /* Fill blocks with 4 colors */
156  case 0xc0:
157  colorA = AV_RB16 (&s->buf[stream_ptr]);
158  stream_ptr += 2;
159  case 0x20:
160  colorB = AV_RB16 (&s->buf[stream_ptr]);
161  stream_ptr += 2;
162 
163  /* sort out the colors */
164  color4[0] = colorB;
165  color4[1] = 0;
166  color4[2] = 0;
167  color4[3] = colorA;
168 
169  /* red components */
170  ta = (colorA >> 10) & 0x1F;
171  tb = (colorB >> 10) & 0x1F;
172  color4[1] |= ((11 * ta + 21 * tb) >> 5) << 10;
173  color4[2] |= ((21 * ta + 11 * tb) >> 5) << 10;
174 
175  /* green components */
176  ta = (colorA >> 5) & 0x1F;
177  tb = (colorB >> 5) & 0x1F;
178  color4[1] |= ((11 * ta + 21 * tb) >> 5) << 5;
179  color4[2] |= ((21 * ta + 11 * tb) >> 5) << 5;
180 
181  /* blue components */
182  ta = colorA & 0x1F;
183  tb = colorB & 0x1F;
184  color4[1] |= ((11 * ta + 21 * tb) >> 5);
185  color4[2] |= ((21 * ta + 11 * tb) >> 5);
186 
187  if (s->size - stream_ptr < n_blocks * 4)
188  return;
189  while (n_blocks--) {
190  block_ptr = row_ptr + pixel_ptr;
191  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
192  index = s->buf[stream_ptr++];
193  for (pixel_x = 0; pixel_x < 4; pixel_x++){
194  idx = (index >> (2 * (3 - pixel_x))) & 0x03;
195  pixels[block_ptr] = color4[idx];
196  block_ptr++;
197  }
198  block_ptr += row_inc;
199  }
200  ADVANCE_BLOCK();
201  }
202  break;
203 
204  /* Fill block with 16 colors */
205  case 0x00:
206  if (s->size - stream_ptr < 16)
207  return;
208  block_ptr = row_ptr + pixel_ptr;
209  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
210  for (pixel_x = 0; pixel_x < 4; pixel_x++){
211  /* We already have color of upper left pixel */
212  if ((pixel_y != 0) || (pixel_x !=0)) {
213  colorA = AV_RB16 (&s->buf[stream_ptr]);
214  stream_ptr += 2;
215  }
216  pixels[block_ptr] = colorA;
217  block_ptr++;
218  }
219  block_ptr += row_inc;
220  }
221  ADVANCE_BLOCK();
222  break;
223 
224  /* Unknown opcode */
225  default:
226  av_log(s->avctx, AV_LOG_ERROR, "Unknown opcode %d in rpza chunk."
227  " Skip remaining %d bytes of chunk data.\n", opcode,
228  chunk_size - stream_ptr);
229  return;
230  } /* Opcode switch */
231  }
232 }
233 
235 {
236  RpzaContext *s = avctx->priv_data;
237 
238  s->avctx = avctx;
239  avctx->pix_fmt = AV_PIX_FMT_RGB555;
240 
242  s->frame.data[0] = NULL;
243 
244  return 0;
245 }
246 
248  void *data, int *got_frame,
249  AVPacket *avpkt)
250 {
251  const uint8_t *buf = avpkt->data;
252  int buf_size = avpkt->size;
253  RpzaContext *s = avctx->priv_data;
254 
255  s->buf = buf;
256  s->size = buf_size;
257 
258  s->frame.reference = 3;
260  if (avctx->reget_buffer(avctx, &s->frame)) {
261  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
262  return -1;
263  }
264 
266 
267  *got_frame = 1;
268  *(AVFrame*)data = s->frame;
269 
270  /* always report that the buffer was completely consumed */
271  return buf_size;
272 }
273 
275 {
276  RpzaContext *s = avctx->priv_data;
277 
278  if (s->frame.data[0])
279  avctx->release_buffer(avctx, &s->frame);
280 
281  return 0;
282 }
283 
285  .name = "rpza",
286  .type = AVMEDIA_TYPE_VIDEO,
287  .id = AV_CODEC_ID_RPZA,
288  .priv_data_size = sizeof(RpzaContext),
292  .capabilities = CODEC_CAP_DR1,
293  .long_name = NULL_IF_CONFIG_SMALL("QuickTime video (RPZA)"),
294 };