avformat/mspdec: Microsoft Paint (MSP) demuxer

Signed-off-by: Peter Ross <pross@xvid.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/libavformat/mspdec.c b/libavformat/mspdec.c
new file mode 100644
index 0000000000..b81d835a63
--- /dev/null
+++ b/libavformat/mspdec.c
@@ -0,0 +1,116 @@
+/*
+ * 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);
+        if (cntx->packet_size < 0)
+            return cntx->packet_size;
+    } else
+        cntx->packet_size = 2 * st->codecpar->height;
+
+    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),
+};