shithub: sox

ref: 7ecafdb3d70342eaf7e5299cb2989bf1967f1e64
dir: /src/flac.c/

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/*
 * Sound Tools File Format: FLAC
 *
 * Support for FLAC input and rudimentary support for FLAC output.
 *
 * (c) 2006 robs@users.sourceforge.net
 *
 * See LICENSE file for further copyright information.
 */



#include "st_i.h"

#if defined(HAVE_LIBFLAC)

#include <math.h>
#include <string.h>

#include <FLAC/all.h>

/* FIXME 
 * There are things that should be const but can't be because
 * of lack of const correctness elsewhere in SoX. 
 * Once Sox has been fixed up, then replace all occurences of 
 * const_ with const and remove this comment and the following
 * line.
 */
#define const_



typedef struct
{
  /* Info: */
  unsigned bits_per_sample;
  unsigned channels;
  unsigned sample_rate;
  unsigned total_samples;

  /* Decode buffer: */
  FLAC__int32 const * const * decoded_wide_samples;
  unsigned number_of_wide_samples;
  unsigned wide_sample_number;

  FLAC__FileDecoder * flac;
  FLAC__bool eof;
} Decoder;



assert_static(sizeof(Decoder) <= ST_MAX_FILE_PRIVSIZE, /* else */ Decoder__PRIVSIZE_too_big);



static void FLAC__decoder_metadata_callback(FLAC__FileDecoder const * const flac, FLAC__StreamMetadata const * const metadata, void * const client_data)
{
  ft_t format = (ft_t) client_data;
  Decoder * decoder = (Decoder *) format->priv;

  (void) flac;

  if (metadata->type == FLAC__METADATA_TYPE_STREAMINFO)
  {
    decoder->bits_per_sample = metadata->data.stream_info.bits_per_sample;
    decoder->channels = metadata->data.stream_info.channels;
    decoder->sample_rate = metadata->data.stream_info.sample_rate;
    decoder->total_samples = metadata->data.stream_info.total_samples;
  }
  else if (metadata->type == FLAC__METADATA_TYPE_VORBIS_COMMENT)
  {
    int i;
    int comment_size = 0;

    if (metadata->data.vorbis_comment.num_comments == 0)
    {
      return;
    }

    if (format->comment != NULL)
    {
      st_warn("FLAC: multiple Vorbis comment block ignored");
      return;
    }

    for (i = 0; i < metadata->data.vorbis_comment.num_comments; ++i)
    {
      comment_size += metadata->data.vorbis_comment.comments[i].length + 1;
    }

    if ((format->comment = (char *) calloc(comment_size, sizeof(char))) == NULL)
    {
      st_fail_errno(format, ST_ENOMEM, "FLAC: Could not allocate memory");
      decoder->eof = true;
      return;
    }

    for (i = 0; i < metadata->data.vorbis_comment.num_comments; ++i)
    {
      strcat(format->comment, (char const *) metadata->data.vorbis_comment.comments[i].entry);
      if (i != metadata->data.vorbis_comment.num_comments - 1)
      {
        strcat(format->comment, "\n");
      }
    }
  }
}



static void FLAC__decoder_error_callback(FLAC__FileDecoder const * const flac, FLAC__StreamDecoderErrorStatus const status, void * const client_data)
{
  ft_t format = (ft_t) client_data;

  (void) flac;

  st_fail_errno(format, ST_EINVAL, "%s", FLAC__StreamDecoderErrorStatusString[status]);
}



static FLAC__StreamDecoderWriteStatus FLAC__frame_decode_callback(FLAC__FileDecoder const * const flac, FLAC__Frame const * const frame, FLAC__int32 const * const buffer[], void * const client_data)
{
  ft_t format = (ft_t) client_data;
  Decoder * decoder = (Decoder *) format->priv;

  (void) flac;

  if (frame->header.bits_per_sample != decoder->bits_per_sample || frame->header.channels != decoder->channels || frame->header.sample_rate != decoder->sample_rate)
  {
    st_fail_errno(format, ST_EINVAL, "FLAC ERROR: parameters differ between frame and header");
    return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
  }

  decoder->decoded_wide_samples = buffer;
  decoder->number_of_wide_samples = frame->header.blocksize;
  decoder->wide_sample_number = 0;
  return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}



static int st_format_start_read(ft_t const format)
{
  Decoder * decoder = (Decoder *) format->priv;

  memset(decoder, 0, sizeof(*decoder));
  decoder->flac = FLAC__file_decoder_new();
  if (decoder->flac == NULL)
  {
    st_fail_errno(format, ST_ENOMEM, "FLAC ERROR creating the decoder instance");
    return ST_EOF;
  }

  FLAC__file_decoder_set_md5_checking(decoder->flac, true);
  FLAC__file_decoder_set_filename(decoder->flac, format->filename);
  FLAC__file_decoder_set_write_callback(decoder->flac, FLAC__frame_decode_callback);
  FLAC__file_decoder_set_metadata_callback(decoder->flac, FLAC__decoder_metadata_callback);
  FLAC__file_decoder_set_error_callback(decoder->flac, FLAC__decoder_error_callback);
  FLAC__file_decoder_set_metadata_respond_all(decoder->flac);
  FLAC__file_decoder_set_client_data(decoder->flac, format);

  if (FLAC__file_decoder_init(decoder->flac) != FLAC__FILE_DECODER_OK)
  {
    st_fail_errno(format, ST_EHDR, "FLAC ERROR initialising decoder");
    return ST_EOF;
  }

  if (!FLAC__file_decoder_process_until_end_of_metadata(decoder->flac))
  {
    st_fail_errno(format, ST_EHDR, "FLAC ERROR whilst decoding metadata");
    return ST_EOF;
  }

  if (FLAC__file_decoder_get_state(decoder->flac) != FLAC__FILE_DECODER_OK && FLAC__file_decoder_get_state(decoder->flac) != FLAC__FILE_DECODER_END_OF_FILE)
  {
    st_fail_errno(format, ST_EHDR, "FLAC ERROR during metadata decoding");
    return ST_EOF;
  }

  format->info.encoding = ST_ENCODING_FLAC;
  format->info.rate = decoder->sample_rate;
  format->info.size = decoder->bits_per_sample >> 3;
  format->info.channels = decoder->channels;
  format->length = decoder->total_samples * decoder->channels;
  return ST_SUCCESS;
}


static st_ssize_t st_format_read(ft_t const format, st_sample_t * sampleBuffer, st_ssize_t const requested)
{
  Decoder * decoder = (Decoder *) format->priv;
  int actual = 0;

  while (!decoder->eof && actual < requested)
  {
    if (decoder->wide_sample_number >= decoder->number_of_wide_samples)
    {
      FLAC__file_decoder_process_single(decoder->flac);
    }
    if (decoder->wide_sample_number >= decoder->number_of_wide_samples)
    {
      decoder->eof = true;
    }
    else
    {
      unsigned channel;

      for (channel = 0; channel < decoder->channels; ++channel)
      {
        FLAC__int32 d = decoder->decoded_wide_samples[channel][decoder->wide_sample_number];
        switch (decoder->bits_per_sample)
        {
          case  8: *sampleBuffer++ = ST_SIGNED_BYTE_TO_SAMPLE(d); break;
          case 16: *sampleBuffer++ = ST_SIGNED_WORD_TO_SAMPLE(d); break;
          case 24: *sampleBuffer++ = ST_SIGNED_24BIT_TO_SAMPLE(d); break;
          case 32: *sampleBuffer++ = ST_SIGNED_DWORD_TO_SAMPLE(d); break;
        }
        ++actual;
      }
      ++decoder->wide_sample_number;
    }
  }
  return actual;
}



static int st_format_stop_read(ft_t const format)
{
  Decoder * decoder = (Decoder *) format->priv;

  int result = FLAC__file_decoder_finish(decoder->flac) ? ST_SUCCESS : ST_EOF;

  if (result == ST_SUCCESS)
  {
    FLAC__file_decoder_delete(decoder->flac);
  }
  return result;
}



typedef struct
{
  /* Info: */
  unsigned bits_per_sample;

  /* Encode buffer: */
  FLAC__int32 * decoded_samples;
  unsigned number_of_samples;

  FLAC__StreamEncoder * flac;
} Encoder;



assert_static(sizeof(Encoder) <= ST_MAX_FILE_PRIVSIZE, /* else */ Encoder__PRIVSIZE_too_big);



FLAC__StreamEncoderWriteStatus flac_stream_encoder_write_callback(FLAC__StreamEncoder const * const flac, const FLAC__byte buffer[], unsigned const bytes, unsigned const samples, unsigned const current_frame, void * const client_data)
{
  ft_t const format = (ft_t) client_data;
  (void) flac, (void) samples, (void) current_frame;

  return st_writebuf(format, buffer, 1, bytes) == bytes ? FLAC__STREAM_ENCODER_WRITE_STATUS_OK : FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
}



void flac_stream_encoder_metadata_callback(FLAC__StreamEncoder const * encoder, FLAC__StreamMetadata const * metadata, void * client_data)
{
  (void) encoder, (void) metadata, (void) client_data;
}



static int st_format_start_write(ft_t const format)
{
  Encoder * encoder = (Encoder *) format->priv;
  FLAC__StreamEncoderState status;

  memset(encoder, 0, sizeof(*encoder));
  encoder->flac = FLAC__stream_encoder_new();
  encoder->decoded_samples = malloc(ST_BUFSIZ * sizeof(FLAC__int32));
  if (encoder->flac == NULL || encoder->decoded_samples == NULL)
  {
    st_fail_errno(format, ST_ENOMEM, "FLAC ERROR creating the encoder instance");
    return ST_EOF;
  }

  {     /* Select and set FLAC encoder options: */
    static struct
    {
      int blocksize;
      FLAC__bool do_exhaustive_model_search;
      FLAC__bool do_mid_side_stereo;
      FLAC__bool loose_mid_side_stereo;
      unsigned max_lpc_order;
      int max_residual_partition_order;
      int min_residual_partition_order;
    } const options[] = {
      {1152, false, false, false, 0, 2, 2},
      {1152, false, true, true, 0, 2, 2},
      {1152, false, true, false, 0, 3, 0},
      {4608, false, false, false, 6, 3, 3},
      {4608, false, true, true, 8, 3, 3},
      {4608, false, true, false, 8, 3, 3},
      {4608, false, true, false, 8, 4, 0},
      {4608, true, true, false, 8, 6, 0},
      {4608, true, true, false, 12, 6, 0},
    };
    unsigned compression_level = array_length(options) - 1; /* Default to "best" */

    if (format->info.compression != HUGE_VAL)
    {
      compression_level = format->info.compression;
      if (compression_level != format->info.compression || 
          compression_level >= array_length(options))
      {
        st_fail_errno(format, ST_EINVAL,
                      "FLAC compression level must be a whole number from 0 to %i",
                      array_length(options) - 1);
        return ST_EOF;
      }
    }

#define SET_OPTION(x) do {\
  st_report("FLAC "#x" = %i", options[compression_level].x); \
  FLAC__stream_encoder_set_##x(encoder->flac, options[compression_level].x);\
} while (0)
    SET_OPTION(blocksize);
    SET_OPTION(do_exhaustive_model_search);
    SET_OPTION(max_lpc_order);
    SET_OPTION(max_residual_partition_order);
    SET_OPTION(min_residual_partition_order);
    if (format->info.channels == 2)
    {
      SET_OPTION(do_mid_side_stereo);
      SET_OPTION(loose_mid_side_stereo);
    }
#undef SET_OPTION
  }

  encoder->bits_per_sample = (format->info.size > 4 ? 4 : format->info.size) << 3;
  st_report("FLAC encoding at %i bits per sample", encoder->bits_per_sample);

  FLAC__stream_encoder_set_channels(encoder->flac, format->info.channels);
  FLAC__stream_encoder_set_bits_per_sample(encoder->flac, encoder->bits_per_sample);
  FLAC__stream_encoder_set_sample_rate(encoder->flac, format->info.rate);

  { /* Check if rate is streamable: */
    static const unsigned streamable_rates[] =
      {8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000};
    int i;
    bool streamable = false;
    for (i = 0; !streamable && i < array_length(streamable_rates); ++i)
    {
       streamable = (streamable_rates[i] == format->info.rate);
    }
    if (!streamable)
    {
      st_report("FLAC: non-standard rate; output may not be streamable");
      FLAC__stream_encoder_set_streamable_subset(encoder->flac, false);
    }
  }

  if (format->length != 0)
  {
    FLAC__stream_encoder_set_total_samples_estimate(encoder->flac, format->length);
  }

  if (format->comment != NULL && * format->comment != '\0')
  {
    FLAC__StreamMetadata * metadata[1];
    FLAC__StreamMetadata_VorbisComment_Entry entry;
    char * comments, * comment, * end_of_comment;

    /* FIXME This is never deleted; does it matter? */
    metadata[0] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT);

    /* Check if there is a FIELD=value pair already in the comment; if not, add one */
    if (strchr(format->comment, '=') == NULL) 
    {
      static const char prepend[] = "COMMENT=";
      comments = malloc(strlen(format->comment) + sizeof(prepend));
      if (comments != NULL)
      {
        strcpy(comments, prepend);
        strcat(comments, format->comment);
      }
    }
    else
    {
      comments = strdup(format->comment);
    }
    if (comments == NULL)
    {
      st_fail_errno(format, ST_ENOMEM, "FLAC ERROR initialising encoder");
      return ST_EOF;
    }
    comment = comments;

    do
    {
      entry.entry = (FLAC__byte *) comment;
      end_of_comment = strchr(comment, '\n');
      if (end_of_comment != NULL)
      {
        *end_of_comment = '\0';
        comment = end_of_comment + 1;
      }
      entry.length = strlen((char const *) entry.entry);

      FLAC__metadata_object_vorbiscomment_append_comment(metadata[0], entry, /*copy= */ true);
    } while (end_of_comment != NULL);

    FLAC__stream_encoder_set_metadata(encoder->flac, metadata, 1);
    free(comments);
  }

  FLAC__stream_encoder_set_write_callback(encoder->flac, flac_stream_encoder_write_callback);
  FLAC__stream_encoder_set_metadata_callback(encoder->flac, flac_stream_encoder_metadata_callback);
  FLAC__stream_encoder_set_client_data(encoder->flac, format);

  status = FLAC__stream_encoder_init(encoder->flac);
  if (status != FLAC__STREAM_ENCODER_OK)
  {
    st_fail_errno(format, ST_EINVAL, "%s", FLAC__StreamEncoderStateString[status]);
    return ST_EOF;
  }
  return ST_SUCCESS;
}



static st_ssize_t st_format_write(ft_t const format, st_sample_t const_ * const sampleBuffer, st_ssize_t const len)
{
  Encoder * encoder = (Encoder *) format->priv;
  unsigned i;

  for (i = 0; i < len; ++i)
  {
    switch (encoder->bits_per_sample)
    {
      case  8: encoder->decoded_samples[i] = ST_SAMPLE_TO_SIGNED_BYTE(sampleBuffer[i]); break;
      case 16: encoder->decoded_samples[i] = ST_SAMPLE_TO_SIGNED_WORD(sampleBuffer[i]); break;
      case 24: encoder->decoded_samples[i] = ST_SAMPLE_TO_SIGNED_24BIT(sampleBuffer[i]); break;
      case 32: encoder->decoded_samples[i] = ST_SAMPLE_TO_SIGNED_DWORD(sampleBuffer[i]); break;
    }
  }
  FLAC__stream_encoder_process_interleaved(encoder->flac, encoder->decoded_samples, len / format->info.channels);
  return FLAC__stream_encoder_get_state(encoder->flac) == FLAC__STREAM_ENCODER_OK ? len : -1;
}



static int st_format_stop_write(ft_t const format)
{
  Encoder * encoder = (Encoder *) format->priv;
  FLAC__StreamEncoderState state = FLAC__stream_encoder_get_state(encoder->flac);

  FLAC__stream_encoder_finish(encoder->flac);
  FLAC__stream_encoder_delete(encoder->flac);
  free(encoder->decoded_samples);
  if (state != FLAC__STREAM_ENCODER_OK)
  {
    st_fail_errno(format, ST_EINVAL, "FLAC ERROR: failed to encode to end of stream");
    return ST_EOF;
  }
  return ST_SUCCESS;
}



static char const_ * const_ st_format_names[] =
{
  "flac",
  NULL
};



static st_format_t const st_format =
{
  st_format_names,
  NULL,
  ST_FILE_STEREO,
  st_format_start_read,
  st_format_read,
  st_format_stop_read,
  st_format_start_write,
  st_format_write,
  st_format_stop_write,
  st_format_nothing_seek
};



st_format_t const * st_flac_format_fn(void)
{
  return &st_format;
}



#endif /* HAVE_LIBFLAC */