3 * Copyright (C) 2003 the ffmpeg project
5 * This file is part of FFmpeg.
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.
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.
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
21 * Creative YUV (CYUV) Video Decoder
22 * by Mike Melanson (melanson@pcisys.net)
23 * based on "Creative YUV (CYUV) stream format for AVI":
24 * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
30 * Creative YUV (CYUV) Video Decoder.
41 #include "mpegvideo.h"
44 typedef struct CyuvDecodeContext {
45 AVCodecContext *avctx;
50 static int cyuv_decode_init(AVCodecContext *avctx)
52 CyuvDecodeContext *s = avctx->priv_data;
55 s->width = avctx->width;
56 /* width needs to be divisible by 4 for this codec to work */
59 s->height = avctx->height;
60 avctx->pix_fmt = PIX_FMT_YUV411P;
61 avctx->has_b_frames = 0;
66 static int cyuv_decode_frame(AVCodecContext *avctx,
67 void *data, int *data_size,
68 uint8_t *buf, int buf_size)
70 CyuvDecodeContext *s=avctx->priv_data;
72 unsigned char *y_plane;
73 unsigned char *u_plane;
74 unsigned char *v_plane;
79 /* prediction error tables (make it clear that they are signed values) */
80 signed char *y_table = (signed char*)buf + 0;
81 signed char *u_table = (signed char*)buf + 16;
82 signed char *v_table = (signed char*)buf + 32;
84 unsigned char y_pred, u_pred, v_pred;
86 unsigned char cur_byte;
89 /* sanity check the buffer size: A buffer has 3x16-bytes tables
90 * followed by (height) lines each with 3 bytes to represent groups
91 * of 4 pixels. Thus, the total size of the buffer ought to be:
92 * (3 * 16) + height * (width * 3 / 4) */
93 if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
94 av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
96 48 + s->height * (s->width * 3 / 4));
100 /* pixel data starts 48 bytes in, after 3x16-byte tables */
104 avctx->release_buffer(avctx, &s->frame);
106 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
107 s->frame.reference = 0;
108 if(avctx->get_buffer(avctx, &s->frame) < 0) {
109 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
113 y_plane = s->frame.data[0];
114 u_plane = s->frame.data[1];
115 v_plane = s->frame.data[2];
117 /* iterate through each line in the height */
118 for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
119 y_ptr < (s->height * s->frame.linesize[0]);
120 y_ptr += s->frame.linesize[0] - s->width,
121 u_ptr += s->frame.linesize[1] - s->width / 4,
122 v_ptr += s->frame.linesize[2] - s->width / 4) {
124 /* reset predictors */
125 cur_byte = buf[stream_ptr++];
126 u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
127 y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
129 cur_byte = buf[stream_ptr++];
130 v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
131 y_pred += y_table[cur_byte & 0x0F];
132 y_plane[y_ptr++] = y_pred;
134 cur_byte = buf[stream_ptr++];
135 y_pred += y_table[cur_byte & 0x0F];
136 y_plane[y_ptr++] = y_pred;
137 y_pred += y_table[(cur_byte & 0xF0) >> 4];
138 y_plane[y_ptr++] = y_pred;
140 /* iterate through the remaining pixel groups (4 pixels/group) */
141 pixel_groups = s->width / 4 - 1;
142 while (pixel_groups--) {
144 cur_byte = buf[stream_ptr++];
145 u_pred += u_table[(cur_byte & 0xF0) >> 4];
146 u_plane[u_ptr++] = u_pred;
147 y_pred += y_table[cur_byte & 0x0F];
148 y_plane[y_ptr++] = y_pred;
150 cur_byte = buf[stream_ptr++];
151 v_pred += v_table[(cur_byte & 0xF0) >> 4];
152 v_plane[v_ptr++] = v_pred;
153 y_pred += y_table[cur_byte & 0x0F];
154 y_plane[y_ptr++] = y_pred;
156 cur_byte = buf[stream_ptr++];
157 y_pred += y_table[cur_byte & 0x0F];
158 y_plane[y_ptr++] = y_pred;
159 y_pred += y_table[(cur_byte & 0xF0) >> 4];
160 y_plane[y_ptr++] = y_pred;
165 *data_size=sizeof(AVFrame);
166 *(AVFrame*)data= s->frame;
171 static int cyuv_decode_end(AVCodecContext *avctx)
173 /* CyuvDecodeContext *s = avctx->priv_data;*/
178 AVCodec cyuv_decoder = {
182 sizeof(CyuvDecodeContext),