FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
8bps.c
Go to the documentation of this file.
1 /*
2  * Quicktime Planar RGB (8BPS) Video Decoder
3  * Copyright (C) 2003 Roberto Togni
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 8BPS Video Decoder by Roberto Togni
25  * For more information about the 8BPS format, visit:
26  * http://www.pcisys.net/~melanson/codecs/
27  *
28  * Supports: PAL8 (RGB 8bpp, paletted)
29  * : BGR24 (RGB 24bpp) (can also output it as RGB32)
30  * : RGB32 (RGB 32bpp, 4th plane is alpha)
31  *
32  */
33 
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 
38 #include "libavutil/internal.h"
39 #include "libavutil/intreadwrite.h"
40 #include "avcodec.h"
41 #include "internal.h"
42 
43 
44 static const enum AVPixelFormat pixfmt_rgb24[] = {
46 
47 typedef struct EightBpsContext {
49 
50  unsigned char planes;
51  unsigned char planemap[4];
52 
53  uint32_t pal[256];
55 
56 static int decode_frame(AVCodecContext *avctx, void *data,
57  int *got_frame, AVPacket *avpkt)
58 {
59  AVFrame *frame = data;
60  const uint8_t *buf = avpkt->data;
61  int buf_size = avpkt->size;
62  EightBpsContext * const c = avctx->priv_data;
63  const unsigned char *encoded = buf;
64  unsigned char *pixptr, *pixptr_end;
65  unsigned int height = avctx->height; // Real image height
66  unsigned int dlen, p, row;
67  const unsigned char *lp, *dp, *ep;
68  unsigned char count;
69  unsigned int planes = c->planes;
70  unsigned char *planemap = c->planemap;
71  int ret;
72 
73  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
74  return ret;
75 
76  ep = encoded + buf_size;
77 
78  /* Set data pointer after line lengths */
79  dp = encoded + planes * (height << 1);
80 
81  for (p = 0; p < planes; p++) {
82  /* Lines length pointer for this plane */
83  lp = encoded + p * (height << 1);
84 
85  /* Decode a plane */
86  for (row = 0; row < height; row++) {
87  pixptr = frame->data[0] + row * frame->linesize[0] + planemap[p];
88  pixptr_end = pixptr + frame->linesize[0];
89  if (ep - lp < row * 2 + 2)
90  return AVERROR_INVALIDDATA;
91  dlen = av_be2ne16(*(const unsigned short *)(lp + row * 2));
92  /* Decode a row of this plane */
93  while (dlen > 0) {
94  if (ep - dp <= 1)
95  return AVERROR_INVALIDDATA;
96  if ((count = *dp++) <= 127) {
97  count++;
98  dlen -= count + 1;
99  if (pixptr_end - pixptr < count * planes)
100  break;
101  if (ep - dp < count)
102  return AVERROR_INVALIDDATA;
103  while (count--) {
104  *pixptr = *dp++;
105  pixptr += planes;
106  }
107  } else {
108  count = 257 - count;
109  if (pixptr_end - pixptr < count * planes)
110  break;
111  while (count--) {
112  *pixptr = *dp;
113  pixptr += planes;
114  }
115  dp++;
116  dlen -= 2;
117  }
118  }
119  }
120  }
121 
122  if (avctx->bits_per_coded_sample <= 8) {
123  const uint8_t *pal = av_packet_get_side_data(avpkt,
125  NULL);
126  if (pal) {
127  frame->palette_has_changed = 1;
128  memcpy(c->pal, pal, AVPALETTE_SIZE);
129  }
130 
131  memcpy (frame->data[1], c->pal, AVPALETTE_SIZE);
132  }
133 
134  *got_frame = 1;
135 
136  /* always report that the buffer was completely consumed */
137  return buf_size;
138 }
139 
141 {
142  EightBpsContext * const c = avctx->priv_data;
143 
144  c->avctx = avctx;
145 
146  switch (avctx->bits_per_coded_sample) {
147  case 8:
148  avctx->pix_fmt = AV_PIX_FMT_PAL8;
149  c->planes = 1;
150  c->planemap[0] = 0; // 1st plane is palette indexes
151  break;
152  case 24:
153  avctx->pix_fmt = ff_get_format(avctx, pixfmt_rgb24);
154  c->planes = 3;
155  c->planemap[0] = 2; // 1st plane is red
156  c->planemap[1] = 1; // 2nd plane is green
157  c->planemap[2] = 0; // 3rd plane is blue
158  break;
159  case 32:
160  avctx->pix_fmt = AV_PIX_FMT_RGB32;
161  c->planes = 4;
162  /* handle planemap setup later for decoding rgb24 data as rbg32 */
163  break;
164  default:
165  av_log(avctx, AV_LOG_ERROR, "Error: Unsupported color depth: %u.\n",
166  avctx->bits_per_coded_sample);
167  return AVERROR_INVALIDDATA;
168  }
169 
170  if (avctx->pix_fmt == AV_PIX_FMT_RGB32) {
171  c->planemap[0] = HAVE_BIGENDIAN ? 1 : 2; // 1st plane is red
172  c->planemap[1] = HAVE_BIGENDIAN ? 2 : 1; // 2nd plane is green
173  c->planemap[2] = HAVE_BIGENDIAN ? 3 : 0; // 3rd plane is blue
174  c->planemap[3] = HAVE_BIGENDIAN ? 0 : 3; // 4th plane is alpha
175  }
176  return 0;
177 }
178 
180  .name = "8bps",
181  .long_name = NULL_IF_CONFIG_SMALL("QuickTime 8BPS video"),
182  .type = AVMEDIA_TYPE_VIDEO,
183  .id = AV_CODEC_ID_8BPS,
184  .priv_data_size = sizeof(EightBpsContext),
185  .init = decode_init,
186  .decode = decode_frame,
187  .capabilities = CODEC_CAP_DR1,
188 };