added demuxer for FunCom ISS audio files,

extended ADPCM decoder by ISS specific IMA variant

Originally committed as revision 16658 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 130 insertions, 0 deletions

diff --git a/libavformat/iss.c b/libavformat/iss.c
new file mode 100644
index 0000000000..4a16318481
--- /dev/null
+++ b/libavformat/iss.c
@@ -0,0 +1,130 @@
+/*
+ * ISS (.iss) file demuxer
+ * Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
+ *
+ * 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 iss.c
+ * Funcom ISS file demuxer
+ * @author Jaikrishnan Menon
+ * for more information on the .iss file format, visit:
+ * http://wiki.multimedia.cx/index.php?title=FunCom_ISS
+ */
+
+#include "avformat.h"
+#include "libavutil/avstring.h"
+
+#define ISS_SIG "IMA_ADPCM_Sound"
+#define ISS_SIG_LEN 15
+#define MAX_TOKEN_SIZE 20
+
+typedef struct {
+    int packet_size;
+    int sample_start_pos;
+} IssDemuxContext;
+
+static void get_token(ByteIOContext *s, char *buf, int maxlen)
+{
+    int i = 0;
+    char c;
+
+    while ((c = get_byte(s))) {
+        if(c == ' ')
+            break;
+        if (i < maxlen-1)
+            buf[i++] = c;
+    }
+
+    buf[i] = 0; /* Ensure null terminated, but may be truncated */
+}
+
+static int iss_probe(AVProbeData *p)
+{
+    if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))
+        return 0;
+
+    return AVPROBE_SCORE_MAX;
+}
+
+static av_cold int iss_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    IssDemuxContext *iss = s->priv_data;
+    ByteIOContext *pb = s->pb;
+    AVStream *st;
+    char token[MAX_TOKEN_SIZE];
+    int stereo, rate_divisor;
+
+    get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"
+    get_token(pb, token, sizeof(token)); //packet size
+    sscanf(token, "%d", &iss->packet_size);
+    get_token(pb, token, sizeof(token)); //File ID
+    get_token(pb, token, sizeof(token)); //out size
+    get_token(pb, token, sizeof(token)); //stereo
+    sscanf(token, "%d", &stereo);
+    get_token(pb, token, sizeof(token)); //Unknown1
+    get_token(pb, token, sizeof(token)); //RateDivisor
+    sscanf(token, "%d", &rate_divisor);
+    get_token(pb, token, sizeof(token)); //Unknown2
+    get_token(pb, token, sizeof(token)); //Version ID
+    get_token(pb, token, sizeof(token)); //Size
+
+    iss->sample_start_pos = url_ftell(pb);
+
+    st = av_new_stream(s, 0);
+    if (!st)
+        return AVERROR(ENOMEM);
+    st->codec->codec_type = CODEC_TYPE_AUDIO;
+    st->codec->codec_id = CODEC_ID_ADPCM_IMA_ISS;
+    st->codec->channels = stereo ? 2 : 1;
+    st->codec->sample_rate = 44100;
+    if(rate_divisor > 0)
+         st->codec->sample_rate /= rate_divisor;
+    st->codec->bits_per_coded_sample = 4;
+    st->codec->bit_rate = st->codec->channels * st->codec->sample_rate
+                                      * st->codec->bits_per_coded_sample;
+    st->codec->block_align = iss->packet_size;
+    av_set_pts_info(st, 32, 1, st->codec->sample_rate);
+
+    return 0;
+}
+
+static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    IssDemuxContext *iss = s->priv_data;
+    int ret = av_get_packet(s->pb, pkt, iss->packet_size);
+
+    if(ret < 0)
+        return ret;
+
+    pkt->stream_index = 0;
+    pkt->pts = url_ftell(s->pb) - iss->sample_start_pos;
+    if(s->streams[0]->codec->channels > 0)
+        pkt->pts /= s->streams[0]->codec->channels*2;
+    return 0;
+}
+
+AVInputFormat iss_demuxer = {
+    "ISS",
+    NULL_IF_CONFIG_SMALL("Funcom ISS format"),
+    sizeof(IssDemuxContext),
+    iss_probe,
+    iss_read_header,
+    iss_read_packet,
+};
+