text: /*
   * AU muxer and demuxer
   * Copyright (c) 2001 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
   */
  
  /*
   * First version by Francois Revol revol@free.fr
   *
   * Reference documents:
   * http://www.opengroup.org/public/pubs/external/auformat.html
   * http://www.goice.co.jp/member/mo/formats/au.html
   */
  
  #include "avformat.h"
  #include "internal.h"
  #include "avio_internal.h"
  #include "pcm.h"
  #include "riff.h"
  
  /* if we don't know the size in advance */
  #define AU_UNKNOWN_SIZE ((uint32_t)(~0))
  
  /* The libavcodec codecs we support, and the IDs they have in the file */
  static const AVCodecTag codec_au_tags[] = {
      { CODEC_ID_PCM_MULAW, 1 },
      { CODEC_ID_PCM_S8, 2 },
      { CODEC_ID_PCM_S16BE, 3 },
      { CODEC_ID_PCM_S24BE, 4 },
      { CODEC_ID_PCM_S32BE, 5 },
      { CODEC_ID_PCM_F32BE, 6 },
      { CODEC_ID_PCM_F64BE, 7 },
      { CODEC_ID_PCM_ALAW, 27 },
      { CODEC_ID_NONE, 0 },
  };
  
  #if CONFIG_AU_MUXER
  /* AUDIO_FILE header */
  static int put_au_header(AVIOContext *pb, AVCodecContext *enc)
  {
      if(!enc->codec_tag)
          return -1;
      ffio_wfourcc(pb, ".snd");    /* magic number */
      avio_wb32(pb, 24);           /* header size */
      avio_wb32(pb, AU_UNKNOWN_SIZE); /* data size */
      avio_wb32(pb, (uint32_t)enc->codec_tag);     /* codec ID */
      avio_wb32(pb, enc->sample_rate);
      avio_wb32(pb, (uint32_t)enc->channels);
      return 0;
  }
  
  static int au_write_header(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
  
      s->priv_data = NULL;
  
      /* format header */
      if (put_au_header(pb, s->streams[0]->codec) < 0) {
          return -1;
      }
  
      avio_flush(pb);
  
      return 0;
  }
  
  static int au_write_packet(AVFormatContext *s, AVPacket *pkt)
  {
      AVIOContext *pb = s->pb;
      avio_write(pb, pkt->data, pkt->size);
      return 0;
  }
  
  static int au_write_trailer(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      int64_t file_size;
  
      if (s->pb->seekable) {
  
          /* update file size */
          file_size = avio_tell(pb);
          avio_seek(pb, 8, SEEK_SET);
          avio_wb32(pb, (uint32_t)(file_size - 24));
          avio_seek(pb, file_size, SEEK_SET);
  
          avio_flush(pb);
      }
  
      return 0;
  }
  #endif /* CONFIG_AU_MUXER */
  
  static int au_probe(AVProbeData *p)
  {
      /* check file header */
      if (p->buf[0] == '.' && p->buf[1] == 's' &&
          p->buf[2] == 'n' && p->buf[3] == 'd')
          return AVPROBE_SCORE_MAX;
      else
          return 0;
  }
  
  /* au input */
  static int au_read_header(AVFormatContext *s)
  {
      int size, bps, data_size = 0;
      unsigned int tag;
      AVIOContext *pb = s->pb;
      unsigned int id, channels, rate;
      enum CodecID codec;
      AVStream *st;
  
      /* check ".snd" header */
      tag = avio_rl32(pb);
      if (tag != MKTAG('.', 's', 'n', 'd'))
          return -1;
      size = avio_rb32(pb); /* header size */
      data_size = avio_rb32(pb); /* data size in bytes */
  
      if (data_size < 0 && data_size != AU_UNKNOWN_SIZE) {
          av_log(s, AV_LOG_ERROR, "Invalid negative data size '%d' found\n", data_size);
          return AVERROR_INVALIDDATA;
      }
  
      id = avio_rb32(pb);
      rate = avio_rb32(pb);
      channels = avio_rb32(pb);
  
      codec = ff_codec_get_id(codec_au_tags, id);
  
      if (!(bps = av_get_bits_per_sample(codec))) {
          av_log_ask_for_sample(s, "could not determine bits per sample\n");
          return AVERROR_INVALIDDATA;
      }
  
      if (channels == 0 || channels > 64) {
          av_log(s, AV_LOG_ERROR, "Invalid number of channels %d\n", channels);
          return AVERROR_INVALIDDATA;
      }
  
      if (size >= 24) {
          /* skip unused data */
          avio_skip(pb, size - 24);
      }
  
      /* now we are ready: build format streams */
      st = avformat_new_stream(s, NULL);
      if (!st)
          return -1;
      st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
      st->codec->codec_tag = id;
      st->codec->codec_id = codec;
      st->codec->channels = channels;
      st->codec->sample_rate = rate;
      if (data_size != AU_UNKNOWN_SIZE)
      st->duration = (((int64_t)data_size)<<3) / (st->codec->channels * (int64_t)bps);
      avpriv_set_pts_info(st, 64, 1, rate);
      return 0;
  }
  
  #define BLOCK_SIZE 1024
  
  static int au_read_packet(AVFormatContext *s,
                            AVPacket *pkt)
  {
      int ret;
  
      ret= av_get_packet(s->pb, pkt, BLOCK_SIZE *
                         s->streams[0]->codec->channels *
                         av_get_bits_per_sample(s->streams[0]->codec->codec_id) >> 3);
      if (ret < 0)
          return ret;
      pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
      pkt->stream_index = 0;
      return 0;
  }
  
  #if CONFIG_AU_DEMUXER
  AVInputFormat ff_au_demuxer = {
      .name           = "au",
      .long_name      = NULL_IF_CONFIG_SMALL("SUN AU format"),
      .read_probe     = au_probe,
      .read_header    = au_read_header,
      .read_packet    = au_read_packet,
      .read_seek      = ff_pcm_read_seek,
      .codec_tag      = (const AVCodecTag* const []){ codec_au_tags, 0 },
  };
  #endif
  
  #if CONFIG_AU_MUXER
  AVOutputFormat ff_au_muxer = {
      .name              = "au",
      .long_name         = NULL_IF_CONFIG_SMALL("SUN AU format"),
      .mime_type         = "audio/basic",
      .extensions        = "au",
      .audio_codec       = CODEC_ID_PCM_S16BE,
      .video_codec       = CODEC_ID_NONE,
      .write_header      = au_write_header,
      .write_packet      = au_write_packet,
      .write_trailer     = au_write_trailer,
      .codec_tag         = (const AVCodecTag* const []){ codec_au_tags, 0 },
  };
  #endif //CONFIG_AU_MUXER
  