Implement the iLBC storage file format

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 141 insertions, 0 deletions

diff --git a/libavformat/ilbc.c b/libavformat/ilbc.c
new file mode 100644
index 0000000000..33aed77163
--- /dev/null
+++ b/libavformat/ilbc.c
@@ -0,0 +1,141 @@
+/*
+ * iLBC storage file format
+ * Copyright (c) 2012 Martin Storsjo
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avformat.h"
+#include "internal.h"
+
+static const char mode20_header[] = "#!iLBC20\n";
+static const char mode30_header[] = "#!iLBC30\n";
+
+static int ilbc_write_header(AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    AVCodecContext *enc;
+
+    if (s->nb_streams != 1) {
+        av_log(s, AV_LOG_ERROR, "Unsupported number of streams\n");
+        return AVERROR(EINVAL);
+    }
+    enc = s->streams[0]->codec;
+
+    if (enc->codec_id != CODEC_ID_ILBC) {
+        av_log(s, AV_LOG_ERROR, "Unsupported codec\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (enc->block_align == 50) {
+        avio_write(pb, mode30_header, sizeof(mode30_header) - 1);
+    } else if (enc->block_align == 38) {
+        avio_write(pb, mode20_header, sizeof(mode20_header) - 1);
+    } else {
+        av_log(s, AV_LOG_ERROR, "Unsupported mode\n");
+        return AVERROR(EINVAL);
+    }
+    avio_flush(pb);
+    return 0;
+}
+
+static int ilbc_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    avio_write(s->pb, pkt->data, pkt->size);
+    avio_flush(s->pb);
+    return 0;
+}
+
+static int ilbc_probe(AVProbeData *p)
+{
+    // Only check for "#!iLBC" which matches both formats
+    if (!memcmp(p->buf, mode20_header, 6))
+        return AVPROBE_SCORE_MAX;
+    else
+        return 0;
+}
+
+static int ilbc_read_header(AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    AVStream *st;
+    uint8_t header[9];
+
+    avio_read(pb, header, 9);
+
+    st = avformat_new_stream(s, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+    st->codec->codec_id = CODEC_ID_ILBC;
+    st->codec->sample_rate = 8000;
+    st->codec->channels = 1;
+    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->start_time = 0;
+    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+    if (!memcmp(header, mode20_header, sizeof(mode20_header) - 1)) {
+        st->codec->block_align = 38;
+        st->codec->bit_rate = 15200;
+    } else if (!memcmp(header, mode30_header, sizeof(mode30_header) - 1)) {
+        st->codec->block_align = 50;
+        st->codec->bit_rate = 13333;
+    } else {
+        av_log(s, AV_LOG_ERROR, "Unrecognized iLBC file header\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
+static int ilbc_read_packet(AVFormatContext *s,
+                          AVPacket *pkt)
+{
+    AVCodecContext *enc = s->streams[0]->codec;
+    int ret;
+
+    if ((ret = av_new_packet(pkt, enc->block_align)) < 0)
+        return ret;
+
+    pkt->stream_index = 0;
+    pkt->pos = avio_tell(s->pb);
+    pkt->duration = enc->block_align == 38 ? 160 : 240;
+    if ((ret = avio_read(s->pb, pkt->data, enc->block_align)) != enc->block_align) {
+        av_free_packet(pkt);
+        return ret < 0 ? ret : AVERROR(EIO);
+    }
+
+    return 0;
+}
+
+AVInputFormat ff_ilbc_demuxer = {
+    .name         = "ilbc",
+    .long_name    = NULL_IF_CONFIG_SMALL("iLBC storage file format"),
+    .read_probe   = ilbc_probe,
+    .read_header  = ilbc_read_header,
+    .read_packet  = ilbc_read_packet,
+    .flags        = AVFMT_GENERIC_INDEX,
+};
+
+AVOutputFormat ff_ilbc_muxer = {
+    .name         = "ilbc",
+    .long_name    = NULL_IF_CONFIG_SMALL("iLBC storage file format"),
+    .mime_type    = "audio/iLBC",
+    .extensions   = "lbc",
+    .audio_codec  = CODEC_ID_ILBC,
+    .write_header = ilbc_write_header,
+    .write_packet = ilbc_write_packet,
+    .flags        = AVFMT_NOTIMESTAMPS,
+};