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  1. /*
  2.  * raw FLAC muxer
  3.  * Copyright (c) 2006-2009 Justin Ruggles
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include "libavcodec/flac.h"
  23. #include "avformat.h"
  24. #include "avio_internal.h"
  25. #include "flacenc.h"
  26. #include "vorbiscomment.h"
  27. #include "libavcodec/bytestream.h"
  28.  
  29.  
  30. static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
  31.                                     int last_block)
  32. {
  33.     avio_w8(pb, last_block ? 0x81 : 0x01);
  34.     avio_wb24(pb, n_padding_bytes);
  35.     ffio_fill(pb, 0, n_padding_bytes);
  36.     return 0;
  37. }
  38.  
  39. static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
  40.                                     int last_block, int bitexact)
  41. {
  42.     const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
  43.     unsigned int len, count;
  44.     uint8_t *p, *p0;
  45.  
  46.     ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
  47.  
  48.     len = ff_vorbiscomment_length(*m, vendor, &count);
  49.     p0 = av_malloc(len+4);
  50.     if (!p0)
  51.         return AVERROR(ENOMEM);
  52.     p = p0;
  53.  
  54.     bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
  55.     bytestream_put_be24(&p, len);
  56.     ff_vorbiscomment_write(&p, m, vendor, count);
  57.  
  58.     avio_write(pb, p0, len+4);
  59.     av_freep(&p0);
  60.     p = NULL;
  61.  
  62.     return 0;
  63. }
  64.  
  65. static int flac_write_header(struct AVFormatContext *s)
  66. {
  67.     int ret;
  68.     AVCodecContext *codec = s->streams[0]->codec;
  69.  
  70.     if (s->nb_streams > 1) {
  71.         av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
  72.         return AVERROR(EINVAL);
  73.     }
  74.     if (codec->codec_id != AV_CODEC_ID_FLAC) {
  75.         av_log(s, AV_LOG_ERROR, "unsupported codec\n");
  76.         return AVERROR(EINVAL);
  77.     }
  78.  
  79.     ret = ff_flac_write_header(s->pb, codec, 0);
  80.     if (ret)
  81.         return ret;
  82.  
  83.     ret = flac_write_block_comment(s->pb, &s->metadata, 0,
  84.                                    codec->flags & CODEC_FLAG_BITEXACT);
  85.     if (ret)
  86.         return ret;
  87.  
  88.     /* The command line flac encoder defaults to placing a seekpoint
  89.      * every 10s.  So one might add padding to allow that later
  90.      * but there seems to be no simple way to get the duration here.
  91.      * So let's try the flac default of 8192 bytes */
  92.     flac_write_block_padding(s->pb, 8192, 1);
  93.  
  94.     return ret;
  95. }
  96.  
  97. static int flac_write_trailer(struct AVFormatContext *s)
  98. {
  99.     AVIOContext *pb = s->pb;
  100.     uint8_t *streaminfo;
  101.     enum FLACExtradataFormat format;
  102.     int64_t file_size;
  103.  
  104.     if (!avpriv_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
  105.         return -1;
  106.  
  107.     if (pb->seekable) {
  108.         /* rewrite the STREAMINFO header block data */
  109.         file_size = avio_tell(pb);
  110.         avio_seek(pb, 8, SEEK_SET);
  111.         avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
  112.         avio_seek(pb, file_size, SEEK_SET);
  113.         avio_flush(pb);
  114.     } else {
  115.         av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
  116.     }
  117.     return 0;
  118. }
  119.  
  120. static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
  121. {
  122.     avio_write(s->pb, pkt->data, pkt->size);
  123.     return 0;
  124. }
  125.  
  126. AVOutputFormat ff_flac_muxer = {
  127.     .name              = "flac",
  128.     .long_name         = NULL_IF_CONFIG_SMALL("raw FLAC"),
  129.     .mime_type         = "audio/x-flac",
  130.     .extensions        = "flac",
  131.     .audio_codec       = AV_CODEC_ID_FLAC,
  132.     .video_codec       = AV_CODEC_ID_NONE,
  133.     .write_header      = flac_write_header,
  134.     .write_packet      = flac_write_packet,
  135.     .write_trailer     = flac_write_trailer,
  136.     .flags             = AVFMT_NOTIMESTAMPS,
  137. };
  138.