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ffmpeg / libavformat / au.c @ 20f269dc

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/* 
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 * AU encoder and decoder
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 * Copyright (c) 2001 Fabrice Bellard.
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 */
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/*
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 * First version by Francois Revol revol@free.fr
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 *
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 * Reference documents:
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 * http://www.opengroup.org/public/pubs/external/auformat.html
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 * http://www.goice.co.jp/member/mo/formats/au.html
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 */
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#include "avformat.h"
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#include "avi.h"
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/* if we don't know the size in advance */
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#define AU_UNKOWN_SIZE ((uint32_t)(~0))
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/* The ffmpeg codecs we support, and the IDs they have in the file */
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static const CodecTag codec_au_tags[] = {
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    { CODEC_ID_PCM_MULAW, 1 },
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    { CODEC_ID_PCM_S16BE, 3 },
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    { CODEC_ID_PCM_ALAW, 27 },
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    { 0, 0 },
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};
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/* AUDIO_FILE header */
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static int put_au_header(ByteIOContext *pb, AVCodecContext *enc)
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{
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    if(!enc->codec_tag)
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       enc->codec_tag = codec_get_tag(codec_au_tags, enc->codec_id);
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    if(!enc->codec_tag)
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        return -1;
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    put_tag(pb, ".snd");       /* magic number */
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    put_be32(pb, 24);           /* header size */
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    put_be32(pb, AU_UNKOWN_SIZE); /* data size */
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    put_be32(pb, (uint32_t)enc->codec_tag);     /* codec ID */
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    put_be32(pb, enc->sample_rate);
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    put_be32(pb, (uint32_t)enc->channels);
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    return 0;
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}
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static int au_write_header(AVFormatContext *s)
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{
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    ByteIOContext *pb = &s->pb;
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    s->priv_data = NULL;
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    /* format header */
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    if (put_au_header(pb, &s->streams[0]->codec) < 0) {
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        return -1;
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    }
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    put_flush_packet(pb);
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    return 0;
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}
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static int au_write_packet(AVFormatContext *s, int stream_index_ptr,
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                           const uint8_t *buf, int size, int64_t pts)
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{
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    ByteIOContext *pb = &s->pb;
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    put_buffer(pb, buf, size);
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    return 0;
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}
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static int au_write_trailer(AVFormatContext *s)
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{
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    ByteIOContext *pb = &s->pb;
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    offset_t file_size;
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    if (!url_is_streamed(&s->pb)) {
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        /* update file size */
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        file_size = url_ftell(pb);
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        url_fseek(pb, 8, SEEK_SET);
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        put_be32(pb, (uint32_t)(file_size - 24));
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        url_fseek(pb, file_size, SEEK_SET);
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        put_flush_packet(pb);
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    }
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    return 0;
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}
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static int au_probe(AVProbeData *p)
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{
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    /* check file header */
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    if (p->buf_size <= 24)
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        return 0;
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    if (p->buf[0] == '.' && p->buf[1] == 's' &&
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        p->buf[2] == 'n' && p->buf[3] == 'd')
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        return AVPROBE_SCORE_MAX;
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    else
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        return 0;
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}
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/* au input */
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static int au_read_header(AVFormatContext *s,
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                           AVFormatParameters *ap)
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{
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    int size;
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    unsigned int tag;
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    ByteIOContext *pb = &s->pb;
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    unsigned int id, codec, channels, rate;
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    AVStream *st;
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    /* check ".snd" header */
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    tag = get_le32(pb);
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    if (tag != MKTAG('.', 's', 'n', 'd'))
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        return -1;
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    size = get_be32(pb); /* header size */
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    get_be32(pb); /* data size */
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    id = get_be32(pb);
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    rate = get_be32(pb);
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    channels = get_be32(pb);
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    codec = codec_get_id(codec_au_tags, id);
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    if (size >= 24) {
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        /* skip unused data */
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        url_fseek(pb, size - 24, SEEK_CUR);
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    }
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    /* now we are ready: build format streams */
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    st = av_new_stream(s, 0);
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    if (!st)
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        return -1;
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    st->codec.codec_type = CODEC_TYPE_AUDIO;
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    st->codec.codec_tag = id;
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    st->codec.codec_id = codec;
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    st->codec.channels = channels;
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    st->codec.sample_rate = rate;
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    return 0;
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}
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#define MAX_SIZE 4096
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static int au_read_packet(AVFormatContext *s,
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                          AVPacket *pkt)
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{
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    int ret;
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    if (url_feof(&s->pb))
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        return -EIO;
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    if (av_new_packet(pkt, MAX_SIZE))
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        return -EIO;
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    pkt->stream_index = 0;
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    ret = get_buffer(&s->pb, pkt->data, pkt->size);
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    if (ret < 0)
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        av_free_packet(pkt);
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    /* note: we need to modify the packet size here to handle the last
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       packet */
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    pkt->size = ret;
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    return 0;
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}
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static int au_read_close(AVFormatContext *s)
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{
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    return 0;
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}
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static AVInputFormat au_iformat = {
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    "au",
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    "SUN AU Format",
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    0,
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    au_probe,
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    au_read_header,
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    au_read_packet,
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    au_read_close,
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};
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static AVOutputFormat au_oformat = {
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    "au",
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    "SUN AU Format",
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    "audio/basic",
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    "au",
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    0,
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    CODEC_ID_PCM_S16BE,
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    CODEC_ID_NONE,
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    au_write_header,
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    au_write_packet,
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    au_write_trailer,
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};
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int au_init(void)
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{
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    av_register_input_format(&au_iformat);
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    av_register_output_format(&au_oformat);
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    return 0;
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}