09c2d08c
 Hu Chunming
arm交付版
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/*
* Microsoft Paint (MSP) demuxer
* Copyright (c) 2020 Peter Ross (pross@xvid.org)
*
* 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
*/
/**
* @file
* Microsoft Paint (MSP) demuxer
*/
#include "libavutil/intreadwrite.h"
#include "libavutil/imgutils.h"
#include "avformat.h"
#include "internal.h"
typedef struct {
int packet_size;
} MSPContext;
static int msp_probe(const AVProbeData *p)
{
unsigned int i, sum;
if (p->buf_size <= 32 || (memcmp(p->buf, "DanM", 4) && memcmp(p->buf, "LinS", 4)))
return 0;
sum = 0;
for (i = 0; i < 24; i += 2)
sum ^= AV_RL16(p->buf + i);
return AV_RL16(p->buf + 24) == sum ? AVPROBE_SCORE_MAX : 0;
}
static int msp_read_header(AVFormatContext *s)
{
MSPContext * cntx = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = avio_rl32(pb) == MKTAG('D', 'a', 'n', 'M') ? AV_CODEC_ID_RAWVIDEO : AV_CODEC_ID_MSP2;
st->codecpar->width = avio_rl16(pb);
st->codecpar->height = avio_rl16(pb);
st->codecpar->format = AV_PIX_FMT_MONOBLACK;
st->sample_aspect_ratio.num = avio_rl16(pb);
st->sample_aspect_ratio.den = avio_rl16(pb);
avio_skip(pb, 20);
if (st->codecpar->codec_id == AV_CODEC_ID_RAWVIDEO) {
cntx->packet_size = av_image_get_buffer_size(st->codecpar->format, st->codecpar->width, st->codecpar->height, 1);
} else
cntx->packet_size = 2 * st->codecpar->height;
if (cntx->packet_size <= 0)
return cntx->packet_size < 0 ? cntx->packet_size : AVERROR_INVALIDDATA;
return 0;
}
static int msp_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AVStream *st = s->streams[0];
MSPContext *cntx = s->priv_data;
int ret;
ret = av_get_packet(s->pb, pkt, cntx->packet_size);
if (ret < 0)
return ret;
if (st->codecpar->codec_id == AV_CODEC_ID_MSP2) {
unsigned int size, i;
if (pkt->size != 2 * st->codecpar->height)
return AVERROR_INVALIDDATA;
size = 0;
for (i = 0; i < st->codecpar->height; i++)
size += AV_RL16(&pkt->data[i * 2]);
ret = av_append_packet(s->pb, pkt, size);
if (ret < 0)
return ret;
}
pkt->stream_index = 0;
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
}
AVInputFormat ff_msp_demuxer = {
.name = "msp",
.long_name = NULL_IF_CONFIG_SMALL("Microsoft Paint (MSP))"),
.read_probe = msp_probe,
.read_header = msp_read_header,
.read_packet = msp_read_packet,
.flags = AVFMT_NOTIMESTAMPS,
.priv_data_size = sizeof(MSPContext),
};
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