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116 lines
3.3 KiB
116 lines
3.3 KiB
/* |
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* Microsoft Paint (MSP) demuxer |
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* Copyright (c) 2020 Peter Ross (pross@xvid.org) |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* Microsoft Paint (MSP) demuxer |
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*/ |
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#include "libavutil/intreadwrite.h" |
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#include "libavutil/imgutils.h" |
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#include "avformat.h" |
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#include "internal.h" |
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typedef struct { |
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int packet_size; |
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} MSPContext; |
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static int msp_probe(const AVProbeData *p) |
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{ |
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unsigned int i, sum; |
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if (p->buf_size <= 32 || (memcmp(p->buf, "DanM", 4) && memcmp(p->buf, "LinS", 4))) |
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return 0; |
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sum = 0; |
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for (i = 0; i < 24; i += 2) |
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sum ^= AV_RL16(p->buf + i); |
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return AV_RL16(p->buf + 24) == sum ? AVPROBE_SCORE_MAX : 0; |
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} |
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static int msp_read_header(AVFormatContext *s) |
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{ |
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MSPContext * cntx = s->priv_data; |
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AVIOContext *pb = s->pb; |
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AVStream *st; |
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st = avformat_new_stream(s, NULL); |
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if (!st) |
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return AVERROR(ENOMEM); |
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st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; |
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st->codecpar->codec_id = avio_rl32(pb) == MKTAG('D', 'a', 'n', 'M') ? AV_CODEC_ID_RAWVIDEO : AV_CODEC_ID_MSP2; |
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st->codecpar->width = avio_rl16(pb); |
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st->codecpar->height = avio_rl16(pb); |
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st->codecpar->format = AV_PIX_FMT_MONOBLACK; |
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st->sample_aspect_ratio.num = avio_rl16(pb); |
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st->sample_aspect_ratio.den = avio_rl16(pb); |
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avio_skip(pb, 20); |
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if (st->codecpar->codec_id == AV_CODEC_ID_RAWVIDEO) { |
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cntx->packet_size = av_image_get_buffer_size(st->codecpar->format, st->codecpar->width, st->codecpar->height, 1); |
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if (cntx->packet_size < 0) |
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return cntx->packet_size; |
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} else |
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cntx->packet_size = 2 * st->codecpar->height; |
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return 0; |
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} |
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static int msp_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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AVStream *st = s->streams[0]; |
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MSPContext *cntx = s->priv_data; |
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int ret; |
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ret = av_get_packet(s->pb, pkt, cntx->packet_size); |
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if (ret < 0) |
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return ret; |
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if (st->codecpar->codec_id == AV_CODEC_ID_MSP2) { |
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unsigned int size, i; |
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if (pkt->size != 2 * st->codecpar->height) |
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return AVERROR_INVALIDDATA; |
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size = 0; |
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for (i = 0; i < st->codecpar->height; i++) |
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size += AV_RL16(&pkt->data[i * 2]); |
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ret = av_append_packet(s->pb, pkt, size); |
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if (ret < 0) |
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return ret; |
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} |
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pkt->stream_index = 0; |
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pkt->flags |= AV_PKT_FLAG_KEY; |
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return 0; |
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} |
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AVInputFormat ff_msp_demuxer = { |
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.name = "msp", |
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.long_name = NULL_IF_CONFIG_SMALL("Microsoft Paint (MSP))"), |
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.read_probe = msp_probe, |
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.read_header = msp_read_header, |
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.read_packet = msp_read_packet, |
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.flags = AVFMT_NOTIMESTAMPS, |
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.priv_data_size = sizeof(MSPContext), |
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};
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