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
27 * @file libavcodec/cyuv.c
28 * Creative YUV (CYUV) Video Decoder.
39 typedef struct CyuvDecodeContext
{
40 AVCodecContext
*avctx
;
45 static av_cold
int cyuv_decode_init(AVCodecContext
*avctx
)
47 CyuvDecodeContext
*s
= avctx
->priv_data
;
50 s
->width
= avctx
->width
;
51 /* width needs to be divisible by 4 for this codec to work */
54 s
->height
= avctx
->height
;
55 avctx
->pix_fmt
= PIX_FMT_YUV411P
;
60 static int cyuv_decode_frame(AVCodecContext
*avctx
,
61 void *data
, int *data_size
,
64 const uint8_t *buf
= avpkt
->data
;
65 int buf_size
= avpkt
->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 const signed char *y_table
= (const signed char*)buf
+ 0;
77 const signed char *u_table
= (const signed char*)buf
+ 16;
78 const signed char *v_table
= (const 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 AVCodec cyuv_decoder
= {
171 sizeof(CyuvDecodeContext
),
178 .long_name
= NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),