1/*
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
6 *
7 * Copyright (C) 2003 the ffmpeg project
8 *
9 * This file is part of FFmpeg.
10 *
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.
15 *
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.
20 *
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
24 */
25
26/**
27 * @file libavcodec/cyuv.c
28 * Creative YUV (CYUV) Video Decoder.
29 */
30
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34#include <unistd.h>
35
36#include "avcodec.h"
37#include "dsputil.h"
38
39
40typedef struct CyuvDecodeContext {
41    AVCodecContext *avctx;
42    int width, height;
43    AVFrame frame;
44} CyuvDecodeContext;
45
46static av_cold int cyuv_decode_init(AVCodecContext *avctx)
47{
48    CyuvDecodeContext *s = avctx->priv_data;
49
50    s->avctx = avctx;
51    s->width = avctx->width;
52    /* width needs to be divisible by 4 for this codec to work */
53    if (s->width & 0x3)
54        return -1;
55    s->height = avctx->height;
56    avctx->pix_fmt = PIX_FMT_YUV411P;
57
58    return 0;
59}
60
61static int cyuv_decode_frame(AVCodecContext *avctx,
62                             void *data, int *data_size,
63                             const uint8_t *buf, int buf_size)
64{
65    CyuvDecodeContext *s=avctx->priv_data;
66
67    unsigned char *y_plane;
68    unsigned char *u_plane;
69    unsigned char *v_plane;
70    int y_ptr;
71    int u_ptr;
72    int v_ptr;
73
74    /* prediction error tables (make it clear that they are signed values) */
75    const signed char *y_table = (const signed char*)buf +  0;
76    const signed char *u_table = (const signed char*)buf + 16;
77    const signed char *v_table = (const signed char*)buf + 32;
78
79    unsigned char y_pred, u_pred, v_pred;
80    int stream_ptr;
81    unsigned char cur_byte;
82    int pixel_groups;
83
84    /* sanity check the buffer size: A buffer has 3x16-bytes tables
85     * followed by (height) lines each with 3 bytes to represent groups
86     * of 4 pixels. Thus, the total size of the buffer ought to be:
87     *    (3 * 16) + height * (width * 3 / 4) */
88    if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
89      av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
90        buf_size,
91        48 + s->height * (s->width * 3 / 4));
92      return -1;
93    }
94
95    /* pixel data starts 48 bytes in, after 3x16-byte tables */
96    stream_ptr = 48;
97
98    if(s->frame.data[0])
99        avctx->release_buffer(avctx, &s->frame);
100
101    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
102    s->frame.reference = 0;
103    if(avctx->get_buffer(avctx, &s->frame) < 0) {
104        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
105        return -1;
106    }
107
108    y_plane = s->frame.data[0];
109    u_plane = s->frame.data[1];
110    v_plane = s->frame.data[2];
111
112    /* iterate through each line in the height */
113    for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
114         y_ptr < (s->height * s->frame.linesize[0]);
115         y_ptr += s->frame.linesize[0] - s->width,
116         u_ptr += s->frame.linesize[1] - s->width / 4,
117         v_ptr += s->frame.linesize[2] - s->width / 4) {
118
119        /* reset predictors */
120        cur_byte = buf[stream_ptr++];
121        u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
122        y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
123
124        cur_byte = buf[stream_ptr++];
125        v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
126        y_pred += y_table[cur_byte & 0x0F];
127        y_plane[y_ptr++] = y_pred;
128
129        cur_byte = buf[stream_ptr++];
130        y_pred += y_table[cur_byte & 0x0F];
131        y_plane[y_ptr++] = y_pred;
132        y_pred += y_table[(cur_byte & 0xF0) >> 4];
133        y_plane[y_ptr++] = y_pred;
134
135        /* iterate through the remaining pixel groups (4 pixels/group) */
136        pixel_groups = s->width / 4 - 1;
137        while (pixel_groups--) {
138
139            cur_byte = buf[stream_ptr++];
140            u_pred += u_table[(cur_byte & 0xF0) >> 4];
141            u_plane[u_ptr++] = u_pred;
142            y_pred += y_table[cur_byte & 0x0F];
143            y_plane[y_ptr++] = y_pred;
144
145            cur_byte = buf[stream_ptr++];
146            v_pred += v_table[(cur_byte & 0xF0) >> 4];
147            v_plane[v_ptr++] = v_pred;
148            y_pred += y_table[cur_byte & 0x0F];
149            y_plane[y_ptr++] = y_pred;
150
151            cur_byte = buf[stream_ptr++];
152            y_pred += y_table[cur_byte & 0x0F];
153            y_plane[y_ptr++] = y_pred;
154            y_pred += y_table[(cur_byte & 0xF0) >> 4];
155            y_plane[y_ptr++] = y_pred;
156
157        }
158    }
159
160    *data_size=sizeof(AVFrame);
161    *(AVFrame*)data= s->frame;
162
163    return buf_size;
164}
165
166AVCodec cyuv_decoder = {
167    "cyuv",
168    CODEC_TYPE_VIDEO,
169    CODEC_ID_CYUV,
170    sizeof(CyuvDecodeContext),
171    cyuv_decode_init,
172    NULL,
173    NULL,
174    cyuv_decode_frame,
175    CODEC_CAP_DR1,
176    NULL,
177    .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
178};
179
180