* amr format - by Johannes Carlsson

Originally committed as revision 1934 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/amr.c

+/* 
+ * amr file format
+ * Copyright (c) 2001 ffmpeg project
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/*
+Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
+
+Only amr narrowband (not amr-wb) is supported for now.
+
+*/
+#include "avformat.h"
+#include "avi.h"
+
+static const unsigned char AMR_header [] = "#!AMR\n";
+
+/* AMR_FILE header */
+static int put_amr_header(ByteIOContext *pb, AVCodecContext *enc)
+{
+    put_tag(pb, AMR_header);       /* magic number */
+    return 0;
+}
+
+static int amr_write_header(AVFormatContext *s)
+{
+    ByteIOContext *pb = &s->pb;
+
+    s->priv_data = NULL;
+
+    /* format header */
+    if (put_amr_header(pb, &s->streams[0]->codec) < 0) {
+        return -1;
+    }
+
+    put_flush_packet(pb);
+
+    return 0;
+}
+
+static int amr_write_packet(AVFormatContext *s, int stream_index_ptr,
+                           uint8_t *buf, int size, int force_pts)
+{
+    put_buffer(&s->pb, buf, size);
+    put_flush_packet(&s->pb);
+    return 0;
+}
+
+static int amr_write_trailer(AVFormatContext *s)
+{
+    return 0;
+}
+
+static int amr_probe(AVProbeData *p)
+{
+    /* check file header */
+    if (p->buf_size < 6)
+        return 0;
+    if(memcmp(p->buf,AMR_header,6)==0)
+        return AVPROBE_SCORE_MAX;
+    else
+        return 0;
+}
+
+/* amr input */
+static int amr_read_header(AVFormatContext *s,
+                           AVFormatParameters *ap)
+{
+    ByteIOContext *pb = &s->pb;
+    AVStream *st;
+    u_int8_t header[6];
+
+    get_buffer(pb, header, 6);
+
+    if(memcmp(header,AMR_header,6)!=0)
+    {
+        return -1;
+    }
+
+    st = av_new_stream(s, 0);
+    if (!st)
+        return AVERROR_NOMEM;
+
+    st->codec.codec_type = CODEC_TYPE_AUDIO;
+    st->codec.codec_tag = CODEC_ID_AMR_NB;
+    st->codec.codec_id = CODEC_ID_AMR_NB;
+    st->codec.channels = 1;
+    st->codec.sample_rate = 8000;
+    return 0;
+}
+
+#define MAX_SIZE 32
+
+static int amr_read_packet(AVFormatContext *s,
+                          AVPacket *pkt)
+{
+    static u_int16_t packed_size[16] = {12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0};
+    u_int8_t toc, q, ft;
+    int read;
+    int size;
+
+    if (url_feof(&s->pb))
+        return -EIO;
+
+    toc=0;
+
+    toc=get_byte(&s->pb);
+
+    q  = (toc >> 2) & 0x01;
+    ft = (toc >> 3) & 0x0F;
+
+    size=packed_size[ft];
+    //printf("amr_read_packet size=%d\n",size);
+
+    if (av_new_packet(pkt, size+1))
+        return -EIO;
+    pkt->stream_index = 0;
+    
+    pkt->data[0]=toc;
+
+    read = get_buffer(&s->pb, pkt->data+1, size);
+
+    if (read != size)
+    {
+        av_free_packet(pkt);
+        return -EIO;
+    }
+
+    return 0;
+}
+
+static int amr_read_close(AVFormatContext *s)
+{
+    return 0;
+}
+
+static AVInputFormat amr_iformat = {
+    "amr",
+    "3gpp amr file format",
+    0,
+    amr_probe,
+    amr_read_header,
+    amr_read_packet,
+    amr_read_close,
+};
+
+static AVOutputFormat amr_oformat = {
+    "amr",
+    "3gpp amr file format",
+    "audio/amr",
+    "amr",
+    0,
+    CODEC_ID_AMR_NB,
+    CODEC_ID_NONE,
+    amr_write_header,
+    amr_write_packet,
+    amr_write_trailer,
+};
+
+int amr_init(void)
+{
+    av_register_input_format(&amr_iformat);
+    av_register_output_format(&amr_oformat);
+    return 0;
+}