2 * Creative YUV (CYUV) Video Decoder
3 * by Mike Melanson (melanson@pcisys.net)
4 * based on "Creative YUV (CYUV) stream format for AVI":
5 * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
7 * Copyright (C) 2003 the ffmpeg project
9 * This file is part of FFmpeg.
11 * FFmpeg is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
16 * FFmpeg is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with FFmpeg; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 * Creative YUV (CYUV) Video Decoder.
38 #include "mpegvideo.h"
41 typedef struct CyuvDecodeContext {
42 AVCodecContext *avctx;
47 static int cyuv_decode_init(AVCodecContext *avctx)
49 CyuvDecodeContext *s = avctx->priv_data;
52 s->width = avctx->width;
53 /* width needs to be divisible by 4 for this codec to work */
56 s->height = avctx->height;
57 avctx->pix_fmt = PIX_FMT_YUV411P;
62 static int cyuv_decode_frame(AVCodecContext *avctx,
63 void *data, int *data_size,
64 uint8_t *buf, int buf_size)
66 CyuvDecodeContext *s=avctx->priv_data;
68 unsigned char *y_plane;
69 unsigned char *u_plane;
70 unsigned char *v_plane;
75 /* prediction error tables (make it clear that they are signed values) */
76 signed char *y_table = (signed char*)buf + 0;
77 signed char *u_table = (signed char*)buf + 16;
78 signed char *v_table = (signed char*)buf + 32;
80 unsigned char y_pred, u_pred, v_pred;
82 unsigned char cur_byte;
85 /* sanity check the buffer size: A buffer has 3x16-bytes tables
86 * followed by (height) lines each with 3 bytes to represent groups
87 * of 4 pixels. Thus, the total size of the buffer ought to be:
88 * (3 * 16) + height * (width * 3 / 4) */
89 if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
90 av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
92 48 + s->height * (s->width * 3 / 4));
96 /* pixel data starts 48 bytes in, after 3x16-byte tables */
100 avctx->release_buffer(avctx, &s->frame);
102 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
103 s->frame.reference = 0;
104 if(avctx->get_buffer(avctx, &s->frame) < 0) {
105 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
109 y_plane = s->frame.data[0];
110 u_plane = s->frame.data[1];
111 v_plane = s->frame.data[2];
113 /* iterate through each line in the height */
114 for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
115 y_ptr < (s->height * s->frame.linesize[0]);
116 y_ptr += s->frame.linesize[0] - s->width,
117 u_ptr += s->frame.linesize[1] - s->width / 4,
118 v_ptr += s->frame.linesize[2] - s->width / 4) {
120 /* reset predictors */
121 cur_byte = buf[stream_ptr++];
122 u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
123 y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
125 cur_byte = buf[stream_ptr++];
126 v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
127 y_pred += y_table[cur_byte & 0x0F];
128 y_plane[y_ptr++] = y_pred;
130 cur_byte = buf[stream_ptr++];
131 y_pred += y_table[cur_byte & 0x0F];
132 y_plane[y_ptr++] = y_pred;
133 y_pred += y_table[(cur_byte & 0xF0) >> 4];
134 y_plane[y_ptr++] = y_pred;
136 /* iterate through the remaining pixel groups (4 pixels/group) */
137 pixel_groups = s->width / 4 - 1;
138 while (pixel_groups--) {
140 cur_byte = buf[stream_ptr++];
141 u_pred += u_table[(cur_byte & 0xF0) >> 4];
142 u_plane[u_ptr++] = u_pred;
143 y_pred += y_table[cur_byte & 0x0F];
144 y_plane[y_ptr++] = y_pred;
146 cur_byte = buf[stream_ptr++];
147 v_pred += v_table[(cur_byte & 0xF0) >> 4];
148 v_plane[v_ptr++] = v_pred;
149 y_pred += y_table[cur_byte & 0x0F];
150 y_plane[y_ptr++] = y_pred;
152 cur_byte = buf[stream_ptr++];
153 y_pred += y_table[cur_byte & 0x0F];
154 y_plane[y_ptr++] = y_pred;
155 y_pred += y_table[(cur_byte & 0xF0) >> 4];
156 y_plane[y_ptr++] = y_pred;
161 *data_size=sizeof(AVFrame);
162 *(AVFrame*)data= s->frame;
167 static int cyuv_decode_end(AVCodecContext *avctx)
169 /* CyuvDecodeContext *s = avctx->priv_data;*/
174 AVCodec cyuv_decoder = {
178 sizeof(CyuvDecodeContext),