1 /*
2 * Copyright (c) 2021 Paul B Mahol
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "libavutil/common.h"
22 #include "avcodec.h"
23 #include "bytestream.h"
24 #include "internal.h"
25
26 typedef struct SimbiosisIMXContext {
27 AVFrame *frame;
28 uint32_t pal[256];
29 uint8_t history[32768];
30 int pos;
31 } SimbiosisIMXContext;
32
imx_decode_init(AVCodecContext * avctx)33 static av_cold int imx_decode_init(AVCodecContext *avctx)
34 {
35 SimbiosisIMXContext *imx = avctx->priv_data;
36
37 avctx->pix_fmt = AV_PIX_FMT_PAL8;
38 avctx->width = 320;
39 avctx->height = 160;
40
41 imx->frame = av_frame_alloc();
42 if (!imx->frame)
43 return AVERROR(ENOMEM);
44
45 return 0;
46 }
47
imx_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)48 static int imx_decode_frame(AVCodecContext *avctx, void *data,
49 int *got_frame, AVPacket *avpkt)
50 {
51 SimbiosisIMXContext *imx = avctx->priv_data;
52 int ret, x, y;
53 buffer_size_t pal_size;
54 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &pal_size);
55 AVFrame *frame = imx->frame;
56 GetByteContext gb;
57
58 if ((ret = ff_reget_buffer(avctx, frame, 0)) < 0)
59 return ret;
60
61 if (pal && pal_size == AVPALETTE_SIZE) {
62 memcpy(imx->pal, pal, pal_size);
63 frame->palette_has_changed = 1;
64 frame->key_frame = 1;
65 } else {
66 frame->key_frame = 0;
67 frame->palette_has_changed = 0;
68 }
69
70 bytestream2_init(&gb, avpkt->data, avpkt->size);
71
72 memcpy(frame->data[1], imx->pal, AVPALETTE_SIZE);
73
74 x = 0, y = 0;
75 while (bytestream2_get_bytes_left(&gb) > 0 &&
76 x < 320 && y < 160) {
77 int b = bytestream2_get_byte(&gb);
78 int len = b & 0x3f;
79 int op = b >> 6;
80 int fill;
81
82 switch (op) {
83 case 3:
84 len = len * 64 + bytestream2_get_byte(&gb);
85 case 0:
86 while (len > 0) {
87 x++;
88 len--;
89 if (x >= 320) {
90 x = 0;
91 y++;
92 }
93 if (y >= 160)
94 break;
95 }
96
97 frame->key_frame = 0;
98 break;
99 case 1:
100 if (len == 0) {
101 int offset = bytestream2_get_le16(&gb);
102
103 if (offset < 0 || offset >= 32768)
104 return AVERROR_INVALIDDATA;
105
106 len = bytestream2_get_byte(&gb);
107 while (len > 0 && offset < 32768) {
108 frame->data[0][x + y * frame->linesize[0]] = imx->history[offset++];
109 x++;
110 len--;
111 if (x >= 320) {
112 x = 0;
113 y++;
114 }
115 if (y >= 160)
116 break;
117 }
118
119 frame->key_frame = 0;
120 } else {
121 while (len > 0) {
122 fill = bytestream2_get_byte(&gb);
123 frame->data[0][x + y * frame->linesize[0]] = fill;
124 if (imx->pos < 32768)
125 imx->history[imx->pos++] = fill;
126 x++;
127 len--;
128 if (x >= 320) {
129 x = 0;
130 y++;
131 }
132 if (y >= 160)
133 break;
134 }
135 }
136 break;
137 case 2:
138 fill = bytestream2_get_byte(&gb);
139
140 while (len > 0) {
141 frame->data[0][x + y * frame->linesize[0]] = fill;
142 x++;
143 len--;
144 if (x >= 320) {
145 x = 0;
146 y++;
147 }
148 if (y >= 160)
149 break;
150 }
151 break;
152 }
153 }
154
155 frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
156
157 if ((ret = av_frame_ref(data, frame)) < 0)
158 return ret;
159
160 *got_frame = 1;
161
162 return avpkt->size;
163 }
164
imx_decode_flush(AVCodecContext * avctx)165 static void imx_decode_flush(AVCodecContext *avctx)
166 {
167 SimbiosisIMXContext *imx = avctx->priv_data;
168
169 av_frame_unref(imx->frame);
170 imx->pos = 0;
171 memset(imx->pal, 0, sizeof(imx->pal));
172 memset(imx->history, 0, sizeof(imx->history));
173 }
174
imx_decode_close(AVCodecContext * avctx)175 static int imx_decode_close(AVCodecContext *avctx)
176 {
177 SimbiosisIMXContext *imx = avctx->priv_data;
178
179 av_frame_free(&imx->frame);
180
181 return 0;
182 }
183
184 AVCodec ff_simbiosis_imx_decoder = {
185 .name = "simbiosis_imx",
186 .long_name = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX Video"),
187 .type = AVMEDIA_TYPE_VIDEO,
188 .id = AV_CODEC_ID_SIMBIOSIS_IMX,
189 .priv_data_size = sizeof(SimbiosisIMXContext),
190 .init = imx_decode_init,
191 .decode = imx_decode_frame,
192 .close = imx_decode_close,
193 .flush = imx_decode_flush,
194 .capabilities = AV_CODEC_CAP_DR1,
195 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
196 FF_CODEC_CAP_INIT_CLEANUP,
197 };
198