Add .bit (de)muxer

libavformat/bit.c

+#include "avformat.h"
+#include "libavcodec/get_bits.h"
+#include "libavcodec/put_bits.h"
+
+#define MAX_FRAME_SIZE 10
+
+#define SYNC_WORD  0x6b21
+#define BIT_0      0x7f
+#define BIT_1      0x81
+
+static int probe(AVProbeData *p)
+{
+    int i;
+    i=AV_RL16(&p->buf[0]);
+av_log(NULL, AV_LOG_ERROR, "bit probe: %x\n", i);
+    if(i != SYNC_WORD)
+        return 0;
+
+    switch(AV_RL16(&p->buf[2]))
+    {
+    case 0x40:
+    case 0x50:
+        return AVPROBE_SCORE_MAX/2;
+    default:
+        return 0;
+    }
+}
+
+static int read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    AVStream* st;
+    ByteIOContext *pb = s->pb;
+
+    st=av_new_stream(s, 0);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    url_fskip(pb, 2);
+    switch(get_le16(pb))
+    {
+        case 0x40:
+            st->codec->bit_rate = 6400;
+            break;
+        case 0x50:
+            st->codec->bit_rate = 8000;
+            break;
+    }
+
+    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->codec->codec_id=CODEC_ID_G729;
+    st->codec->sample_rate=8000;
+    st->codec->block_align = 16;
+    st->codec->channels=1;
+
+    av_set_pts_info(st, 64, 1, 100);
+    url_fseek(pb, 0, SEEK_SET);
+    return 0;
+}
+
+static int read_packet(AVFormatContext *s,
+                          AVPacket *pkt)
+{
+    ByteIOContext *pb = s->pb;
+    PutBitContext pbo;
+    uint16_t buf[8 * MAX_FRAME_SIZE + 2];
+    int packet_size;
+    int sync;
+    uint16_t* src=buf;
+    int i, j, ret;
+
+    if(url_feof(pb))
+        return AVERROR(EIO);
+
+    sync = get_le16(pb); // sync word
+    packet_size = get_le16(pb) / 8;
+    assert(packet_size < 8 * MAX_FRAME_SIZE);
+
+    ret = get_buffer(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t));
+    if(ret<0)
+        return ret;
+    if(ret != 8 * packet_size * sizeof(uint16_t))
+        return AVERROR(EIO);
+
+    av_new_packet(pkt, packet_size);
+
+    init_put_bits(&pbo, pkt->data, packet_size);
+    for(j=0; j < packet_size; j++)
+        for(i=0; i<8;i++)
+            put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0);
+
+    flush_put_bits(&pbo);
+
+    pkt->duration=1;
+    return 0;
+}
+
+AVInputFormat ff_bit_demuxer = {
+    "bit",
+    "G.729 BIT file format",
+    0,
+    probe,
+    read_header,
+    read_packet,
+    .extensions = "bit"
+};
+
+#ifdef CONFIG_MUXERS
+static int write_header(AVFormatContext *s)
+{
+    AVCodecContext *enc = s->streams[0]->codec;
+
+    enc->codec_id = CODEC_ID_G729;
+    enc->channels = 1;
+    enc->bits_per_coded_sample = 16;
+    enc->block_align = (enc->bits_per_coded_sample * enc->channels) >> 3;
+
+    return 0;
+}
+
+static int write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    ByteIOContext *pb = s->pb;
+    GetBitContext gb;
+    int i;
+    uint16_t b;
+
+    put_le16(pb, SYNC_WORD);
+    put_le16(pb, 8 * 10);
+
+    init_get_bits(&gb, pkt->data, 8*10);
+    for(i=0; i< 8 * 10; i++)
+        put_le16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
+    put_flush_packet(pb);
+
+    return 0;
+}
+
+AVOutputFormat ff_bit_muxer = {
+    "bit",
+    "G.729 BIT file format",
+    "audio/bit",
+    "bit",
+    0,
+    CODEC_ID_G729,
+    CODEC_ID_NONE,
+    write_header,
+    write_packet,
+    .extensions = "bit"
+};
+#endif