flacenc.c 3.8 KB

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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. #include "libavcodec/flac.h"
  22. #include "avformat.h"
  23. #include "flacenc.h"
  24. #include "vorbiscomment.h"
  25. #include "libavcodec/bytestream.h"
  26. static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
  27. int last_block)
  28. {
  29. avio_w8(pb, last_block ? 0x81 : 0x01);
  30. avio_wb24(pb, n_padding_bytes);
  31. while (n_padding_bytes > 0) {
  32. avio_w8(pb, 0);
  33. n_padding_bytes--;
  34. }
  35. return 0;
  36. }
  37. static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
  38. int last_block, int bitexact)
  39. {
  40. const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
  41. unsigned int len, count;
  42. uint8_t *p, *p0;
  43. ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
  44. len = ff_vorbiscomment_length(*m, vendor, &count);
  45. p0 = av_malloc(len+4);
  46. if (!p0)
  47. return AVERROR(ENOMEM);
  48. p = p0;
  49. bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
  50. bytestream_put_be24(&p, len);
  51. ff_vorbiscomment_write(&p, m, vendor, count);
  52. avio_write(pb, p0, len+4);
  53. av_freep(&p0);
  54. p = NULL;
  55. return 0;
  56. }
  57. static int flac_write_header(struct AVFormatContext *s)
  58. {
  59. int ret;
  60. AVCodecContext *codec = s->streams[0]->codec;
  61. ret = ff_flac_write_header(s->pb, codec, 0);
  62. if (ret)
  63. return ret;
  64. ret = flac_write_block_comment(s->pb, &s->metadata, 0,
  65. codec->flags & CODEC_FLAG_BITEXACT);
  66. if (ret)
  67. return ret;
  68. /* The command line flac encoder defaults to placing a seekpoint
  69. * every 10s. So one might add padding to allow that later
  70. * but there seems to be no simple way to get the duration here.
  71. * So let's try the flac default of 8192 bytes */
  72. flac_write_block_padding(s->pb, 8192, 1);
  73. return ret;
  74. }
  75. static int flac_write_trailer(struct AVFormatContext *s)
  76. {
  77. AVIOContext *pb = s->pb;
  78. uint8_t *streaminfo;
  79. enum FLACExtradataFormat format;
  80. int64_t file_size;
  81. if (!avpriv_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
  82. return -1;
  83. if (pb->seekable) {
  84. /* rewrite the STREAMINFO header block data */
  85. file_size = avio_tell(pb);
  86. avio_seek(pb, 8, SEEK_SET);
  87. avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
  88. avio_seek(pb, file_size, SEEK_SET);
  89. avio_flush(pb);
  90. } else {
  91. av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
  92. }
  93. return 0;
  94. }
  95. static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
  96. {
  97. avio_write(s->pb, pkt->data, pkt->size);
  98. avio_flush(s->pb);
  99. return 0;
  100. }
  101. AVOutputFormat ff_flac_muxer = {
  102. .name = "flac",
  103. .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
  104. .mime_type = "audio/x-flac",
  105. .extensions = "flac",
  106. .audio_codec = CODEC_ID_FLAC,
  107. .video_codec = CODEC_ID_NONE,
  108. .write_header = flac_write_header,
  109. .write_packet = flac_write_packet,
  110. .write_trailer = flac_write_trailer,
  111. .flags= AVFMT_NOTIMESTAMPS,
  112. };