ffmpeg/libavformat/imx.c

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/*
* Simbiosis game demuxer
*
* 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 "avformat.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/avassert.h"
#include "libavutil/internal.h"
#define IMX_TAG MKTAG('I', 'M', 'A', 'X')
typedef struct SimbiosisIMXDemuxContext {
uint8_t pal[AVPALETTE_SIZE];
int pal_changed;
int64_t first_video_packet_pos;
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} SimbiosisIMXDemuxContext;
static int simbiosis_imx_probe(const AVProbeData *p)
{
if (AV_RL32(p->buf) != IMX_TAG)
return 0;
if (AV_RN32(p->buf+4) == 0)
return 0;
if (AV_RN16(p->buf+8) == 0)
return 0;
if (AV_RL16(p->buf+10) != 0x102)
return 0;
return AVPROBE_SCORE_EXTENSION + 10;
}
static int simbiosis_imx_read_header(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
AVStream *vst, *ast;
int rate;
vst = avformat_new_stream(s, NULL);
ast = avformat_new_stream(s, NULL);
if (!vst || !ast)
return AVERROR(ENOMEM);
avio_skip(pb, 4);
vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
vst->codecpar->codec_tag = 0;
vst->codecpar->format = AV_PIX_FMT_PAL8;
vst->codecpar->codec_id = AV_CODEC_ID_SIMBIOSIS_IMX;
vst->start_time = 0;
vst->duration =
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vst->nb_frames = avio_rl32(pb);
rate = avio_rl16(pb);
avio_skip(pb, 12);
avpriv_set_pts_info(vst, 64, 1, rate);
ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
ast->codecpar->codec_tag = 0;
ast->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
ast->codecpar->channels = 1;
ast->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
ast->codecpar->sample_rate = 22050;
ast->start_time = 0;
avpriv_set_pts_info(ast, 64, 1, 22050);
return 0;
}
static int simbiosis_imx_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AVIOContext *pb = s->pb;
SimbiosisIMXDemuxContext *imx = s->priv_data;
uint32_t chunk_size, chunk_type;
int64_t pos = avio_tell(pb);
int ret, idx = -1;
retry:
if (avio_feof(pb))
return AVERROR_EOF;
chunk_size = avio_rl32(pb);
chunk_type = avio_rl32(pb);
switch (chunk_type) {
case 0xAAFF:
return AVERROR_EOF;
case 0xAA99:
idx = 1;
break;
case 0xAA97:
idx = 0;
if (!imx->first_video_packet_pos)
imx->first_video_packet_pos = pos;
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break;
case 0xAA98:
if (chunk_size > 256 * 3)
return AVERROR_INVALIDDATA;
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for (int i = 0; i < chunk_size / 3; i++) {
unsigned r = avio_r8(pb) << 18;
unsigned g = avio_r8(pb) << 10;
unsigned b = avio_r8(pb) << 2;
AV_WL32(imx->pal + i * 4, (0xFFU << 24) | r | g | b);
}
imx->pal_changed = 1;
idx = -1;
break;
default:
return AVERROR_INVALIDDATA;
}
if (idx == -1)
goto retry;
ret = av_get_packet(pb, pkt, chunk_size);
if (ret < 0)
return ret;
if (imx->pal_changed && idx == 0) {
uint8_t *pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
AVPALETTE_SIZE);
if (!pal)
return AVERROR(ENOMEM);
memcpy(pal, imx->pal, AVPALETTE_SIZE);
imx->pal_changed = 0;
if (pos <= imx->first_video_packet_pos)
pkt->flags |= AV_PKT_FLAG_KEY;
} else if (idx == 1) {
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pkt->flags |= AV_PKT_FLAG_KEY;
}
pkt->pos = pos;
pkt->stream_index = idx;
pkt->duration = idx ? chunk_size : 1;
return ret;
}
AVInputFormat ff_simbiosis_imx_demuxer = {
.name = "simbiosis_imx",
.long_name = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX"),
.priv_data_size = sizeof(SimbiosisIMXDemuxContext),
.read_probe = simbiosis_imx_probe,
.read_header = simbiosis_imx_read_header,
.read_packet = simbiosis_imx_read_packet,
.extensions = "imx",
.flags = AVFMT_GENERIC_INDEX,
};