Split mp3 demuxer and muxer into separate files.

Signed-off-by: Mans Rullgard <mans@mansr.com>

1 files changed, 192 insertions, 0 deletions

diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c
new file mode 100644
index 0000000000..ab6aabe0b5
--- /dev/null
+++ b/libavformat/mp3dec.c
@@ -0,0 +1,192 @@
+/*
+ * MP3 demuxer
+ * Copyright (c) 2003 Fabrice Bellard
+ *
+ * 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 "libavutil/avstring.h"
+#include "libavutil/intreadwrite.h"
+#include "avformat.h"
+#include "id3v2.h"
+#include "id3v1.h"
+#include "libavcodec/mpegaudiodecheader.h"
+
+/* mp3 read */
+
+static int mp3_read_probe(AVProbeData *p)
+{
+    int max_frames, first_frames = 0;
+    int fsize, frames, sample_rate;
+    uint32_t header;
+    uint8_t *buf, *buf0, *buf2, *end;
+    AVCodecContext avctx;
+
+    buf0 = p->buf;
+    end = p->buf + p->buf_size - sizeof(uint32_t);
+    while(buf0 < end && !*buf0)
+        buf0++;
+
+    max_frames = 0;
+    buf = buf0;
+
+    for(; buf < end; buf= buf2+1) {
+        buf2 = buf;
+
+        for(frames = 0; buf2 < end; frames++) {
+            header = AV_RB32(buf2);
+            fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
+            if(fsize < 0)
+                break;
+            buf2 += fsize;
+        }
+        max_frames = FFMAX(max_frames, frames);
+        if(buf == buf0)
+            first_frames= frames;
+    }
+    // keep this in sync with ac3 probe, both need to avoid
+    // issues with MPEG-files!
+    if   (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
+    else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
+    else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
+    else if(max_frames>=1) return 1;
+    else                   return 0;
+//mpegps_mp3_unrecognized_format.mpg has max_frames=3
+}
+
+/**
+ * Try to find Xing/Info/VBRI tags and compute duration from info therein
+ */
+static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
+{
+    uint32_t v, spf;
+    unsigned frames = 0; /* Total number of frames in file */
+    unsigned size = 0; /* Total number of bytes in the stream */
+    const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
+    MPADecodeHeader c;
+    int vbrtag_size = 0;
+
+    v = get_be32(s->pb);
+    if(ff_mpa_check_header(v) < 0)
+      return -1;
+
+    if (ff_mpegaudio_decode_header(&c, v) == 0)
+        vbrtag_size = c.frame_size;
+    if(c.layer != 3)
+        return -1;
+
+    /* Check for Xing / Info tag */
+    url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
+    v = get_be32(s->pb);
+    if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
+        v = get_be32(s->pb);
+        if(v & 0x1)
+            frames = get_be32(s->pb);
+        if(v & 0x2)
+            size = get_be32(s->pb);
+    }
+
+    /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
+    url_fseek(s->pb, base + 4 + 32, SEEK_SET);
+    v = get_be32(s->pb);
+    if(v == MKBETAG('V', 'B', 'R', 'I')) {
+        /* Check tag version */
+        if(get_be16(s->pb) == 1) {
+            /* skip delay and quality */
+            url_fseek(s->pb, 4, SEEK_CUR);
+            frames = get_be32(s->pb);
+            size = get_be32(s->pb);
+        }
+    }
+
+    if(!frames && !size)
+        return -1;
+
+    /* Skip the vbr tag frame */
+    url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
+
+    spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
+    if(frames)
+        st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
+                                    st->time_base);
+    if(size && frames)
+        st->codec->bit_rate = av_rescale(size, 8 * c.sample_rate, frames * (int64_t)spf);
+
+    return 0;
+}
+
+static int mp3_read_header(AVFormatContext *s,
+                           AVFormatParameters *ap)
+{
+    AVStream *st;
+    int64_t off;
+
+    st = av_new_stream(s, 0);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->codec->codec_id = CODEC_ID_MP3;
+    st->need_parsing = AVSTREAM_PARSE_FULL;
+    st->start_time = 0;
+
+    // lcm of all mp3 sample rates
+    av_set_pts_info(st, 64, 1, 14112000);
+
+    off = url_ftell(s->pb);
+
+    if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
+        ff_id3v1_read(s);
+
+    if (mp3_parse_vbr_tags(s, st, off) < 0)
+        url_fseek(s->pb, off, SEEK_SET);
+
+    /* the parameters will be extracted from the compressed bitstream */
+    return 0;
+}
+
+#define MP3_PACKET_SIZE 1024
+
+static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int ret, size;
+    //    AVStream *st = s->streams[0];
+
+    size= MP3_PACKET_SIZE;
+
+    ret= av_get_packet(s->pb, pkt, size);
+
+    pkt->stream_index = 0;
+    if (ret <= 0) {
+        return AVERROR(EIO);
+    }
+    /* note: we need to modify the packet size here to handle the last
+       packet */
+    pkt->size = ret;
+    return ret;
+}
+
+AVInputFormat mp3_demuxer = {
+    "mp3",
+    NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
+    0,
+    mp3_read_probe,
+    mp3_read_header,
+    mp3_read_packet,
+    .flags= AVFMT_GENERIC_INDEX,
+    .extensions = "mp2,mp3,m2a", /* XXX: use probe */
+};