ffmpeg/libavcodec/imx.c

154 lines
4.5 KiB
C

/*
* Copyright (c) 2021 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/common.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
typedef struct SimbiosisIMXContext {
uint32_t pal[256];
uint8_t history[32768];
int pos;
} SimbiosisIMXContext;
static av_cold int imx_decode_init(AVCodecContext *avctx)
{
avctx->pix_fmt = AV_PIX_FMT_PAL8;
avctx->width = 320;
avctx->height = 160;
return 0;
}
static int imx_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
SimbiosisIMXContext *imx = avctx->priv_data;
int ret, x, y, pal_size;
const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &pal_size);
AVFrame *frame = data;
GetByteContext gb;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
if (pal && pal_size == AVPALETTE_SIZE) {
memcpy(imx->pal, pal, pal_size);
frame->palette_has_changed = 1;
}
bytestream2_init(&gb, avpkt->data, avpkt->size);
memcpy(frame->data[1], imx->pal, AVPALETTE_SIZE);
x = 0, y = 0;
while (bytestream2_get_bytes_left(&gb) > 0 &&
x < 320 && y < 160) {
int b = bytestream2_get_byte(&gb);
int len = b & 0x3f;
int op = b >> 6;
int fill;
switch (op) {
case 3:
len = len * 64 + bytestream2_get_byte(&gb);
case 0:
while (len > 0) {
x++;
len--;
if (x >= 320) {
x = 0;
y++;
}
if (y >= 160)
break;
}
break;
case 1:
if (len == 0) {
int offset = bytestream2_get_le16(&gb);
if (offset < 0 || offset >= 32768)
return AVERROR_INVALIDDATA;
len = bytestream2_get_byte(&gb);
while (len > 0 && offset < 32768) {
frame->data[0][x + y * frame->linesize[0]] = imx->history[offset++];
x++;
len--;
if (x >= 320) {
x = 0;
y++;
}
if (y >= 160)
break;
}
} else {
while (len > 0) {
fill = bytestream2_get_byte(&gb);
frame->data[0][x + y * frame->linesize[0]] = fill;
if (imx->pos < 32768)
imx->history[imx->pos++] = fill;
x++;
len--;
if (x >= 320) {
x = 0;
y++;
}
if (y >= 160)
break;
}
}
break;
case 2:
fill = bytestream2_get_byte(&gb);
while (len > 0) {
frame->data[0][x + y * frame->linesize[0]] = fill;
x++;
len--;
if (x >= 320) {
x = 0;
y++;
}
if (y >= 160)
break;
}
break;
}
}
*got_frame = 1;
return avpkt->size;
}
AVCodec ff_simbiosis_imx_decoder = {
.name = "simbiosis_imx",
.long_name = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX Video"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_SIMBIOSIS_IMX,
.priv_data_size = sizeof(SimbiosisIMXContext),
.init = imx_decode_init,
.decode = imx_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};