From 670c78479d88c86ebf1828f31a5716c54d74d257 Mon Sep 17 00:00:00 2001
From: Ivo van Poorten <ivop@euronet.nl>
Date: Mon, 7 Jan 2008 23:52:51 +0000
Subject: Linux Media Labs MPEG-4 (LMLM4) demuxer

Originally committed as revision 11456 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavformat/lmlm4.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 libavformat/lmlm4.c

(limited to 'libavformat/lmlm4.c')

diff --git a/libavformat/lmlm4.c b/libavformat/lmlm4.c
new file mode 100644
index 0000000000..6646a412bc
--- /dev/null
+++ b/libavformat/lmlm4.c
@@ -0,0 +1,126 @@
+/*
+ * Linux Media Labs MPEG-4 demuxer
+ * Copyright (c) 2008 Ivo van Poorten
+ *
+ * Due to a lack of sample files, only files with one channel are supported.
+ * u-law and ADPCM audio are unsupported for the same reason.
+ *
+ * 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"
+
+#define LMLM4_I_FRAME   0x00
+#define LMLM4_P_FRAME   0x01
+#define LMLM4_B_FRAME   0x02
+#define LMLM4_INVALID   0x03
+#define LMLM4_MPEG1L2   0x04
+
+#define LMLM4_MAX_PACKET_SIZE   1024 * 1024
+
+static int lmlm4_probe(AVProbeData * pd) {
+    unsigned char *buf = pd->buf;
+    unsigned int frame_type, packet_size;
+
+    frame_type  = AV_RB16(buf+2);
+    packet_size = AV_RB32(buf+4);
+
+    if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
+        frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
+
+        if (frame_type == LMLM4_MPEG1L2) {
+            if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
+                return 0;
+            /* I could calculate the audio framesize and compare with
+             * packet_size-8, but that seems overkill */
+            return AVPROBE_SCORE_MAX / 3;
+        } else if (AV_RB24(buf+8) == 0x000001) {    /* PES Signal */
+            return AVPROBE_SCORE_MAX / 5;
+        }
+    }
+
+    return 0;
+}
+
+static int lmlm4_read_header(AVFormatContext *s, AVFormatParameters *ap) {
+    AVStream *st;
+
+    if (!(st = av_new_stream(s, 0)))
+        return AVERROR(ENOMEM);
+    st->codec->codec_type = CODEC_TYPE_VIDEO;
+    st->codec->codec_id   = CODEC_ID_MPEG4;
+    st->need_parsing      = AVSTREAM_PARSE_HEADERS;
+    av_set_pts_info(st, 64, 1001, 30000);
+
+    if (!(st = av_new_stream(s, 1)))
+        return AVERROR(ENOMEM);
+    st->codec->codec_type = CODEC_TYPE_AUDIO;
+    st->codec->codec_id   = CODEC_ID_MP2;
+    st->need_parsing      = AVSTREAM_PARSE_HEADERS;
+
+    /* the parameters will be extracted from the compressed bitstream */
+    return 0;
+}
+
+static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
+    ByteIOContext *pb = s->pb;
+    int ret;
+    unsigned int frame_type, packet_size, padding, frame_size;
+
+    get_be16(pb);                       /* channel number */
+    frame_type  = get_be16(pb);
+    packet_size = get_be32(pb);
+    padding     = -packet_size & 511;
+    frame_size  = packet_size - 8;
+
+    if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
+        av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
+        return AVERROR(EIO);
+    }
+    if (packet_size > LMLM4_MAX_PACKET_SIZE) {
+        av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");
+        return AVERROR(EIO);
+    }
+
+    if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
+        return AVERROR(EIO);
+
+    url_fskip(pb, padding);
+
+    switch (frame_type) {
+        case LMLM4_I_FRAME:
+            pkt->flags = PKT_FLAG_KEY;
+        case LMLM4_P_FRAME:
+        case LMLM4_B_FRAME:
+            pkt->stream_index = 0;
+            break;
+        case LMLM4_MPEG1L2:
+            pkt->stream_index = 1;
+            break;
+    }
+
+    return ret;
+}
+
+AVInputFormat lmlm4_demuxer = {
+    "lmlm4",
+    "lmlm4 raw format",
+    0,
+    lmlm4_probe,
+    lmlm4_read_header,
+    lmlm4_read_packet,
+};
-- 
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