Diff: frame.cpp

Revision:

4:30b2cf4a8ee2

Parent:

3:6f07b5f52c38

Child:

5:50015f4868e2

--- a/frame.cpp	Wed Dec 19 06:01:00 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,502 +0,0 @@
-/*
- * libmad - MPEG audio decoder library
- * Copyright (C) 2000-2004 Underbit Technologies, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * $Id: frame.c,v 1.1 2010/11/23 20:12:57 andy Exp $
- */
-
-#  include "config.h"
-
-# include "global.h"
-
-# include <stdlib.h>
-
-# include "bit.h"
-# include "stream.h"
-# include "frame.h"
-# include "timer.h"
-# include "layer12.h"
-# include "layer3.h"
-
-static
-unsigned long const bitrate_table[5][15] = {
-  /* MPEG-1 */
-  { 0,  32000,  64000,  96000, 128000, 160000, 192000, 224000,  /* Layer I   */
-       256000, 288000, 320000, 352000, 384000, 416000, 448000 },
-  { 0,  32000,  48000,  56000,  64000,  80000,  96000, 112000,  /* Layer II  */
-       128000, 160000, 192000, 224000, 256000, 320000, 384000 },
-  { 0,  32000,  40000,  48000,  56000,  64000,  80000,  96000,  /* Layer III */
-       112000, 128000, 160000, 192000, 224000, 256000, 320000 },
-
-  /* MPEG-2 LSF */
-  { 0,  32000,  48000,  56000,  64000,  80000,  96000, 112000,  /* Layer I   */
-       128000, 144000, 160000, 176000, 192000, 224000, 256000 },
-  { 0,   8000,  16000,  24000,  32000,  40000,  48000,  56000,  /* Layers    */
-        64000,  80000,  96000, 112000, 128000, 144000, 160000 } /* II & III  */
-};
-
-static
-unsigned int const samplerate_table[3] = { 44100, 48000, 32000 };
-
-static
-int (*const decoder_table[3])(struct mad_stream *, struct mad_frame *) = {
-  mad_layer_I,
-  mad_layer_II,
-  mad_layer_III
-};
-
-/*
- * NAME:	header->init()
- * DESCRIPTION:	initialize header struct
- */
-void mad_header_init(struct mad_header *header)
-{
-  header->layer          = (enum mad_layer)0;
-  header->mode           = (enum mad_mode)0;
-  header->mode_extension = 0;
-  header->emphasis       = (enum mad_emphasis)0;
-
-  header->bitrate        = 0;
-  header->samplerate     = 0;
-
-  header->crc_check      = 0;
-  header->crc_target     = 0;
-
-  header->flags          = 0;
-  header->private_bits   = 0;
-
-  header->duration       = mad_timer_zero;
-}
-
-/*
- * NAME:	frame->init()
- * DESCRIPTION:	initialize frame struct
- */
-void mad_frame_init(struct mad_frame *frame)
-{
-  mad_header_init(&frame->header);
-
-  frame->options = 0;
-
-//###  frame->overlap = 0;
-  mad_frame_mute(frame);
-}
-
-/*
- * NAME:	frame->finish()
- * DESCRIPTION:	deallocate any dynamic memory associated with frame
- */
-void mad_frame_finish(struct mad_frame *frame)
-{
-  mad_header_finish(&frame->header);
-/* ###
-  if (frame->overlap) {
-    free(frame->overlap);
-    frame->overlap = 0;
-  }
-  */
-}
-
-/*
- * NAME:	decode_header()
- * DESCRIPTION:	read header data and following CRC word
- */
-static
-int decode_header(struct mad_header *header, struct mad_stream *stream)
-{
-  unsigned int index;
-
-  header->flags        = 0;
-  header->private_bits = 0;
-
-  /* header() */
-
-  /* syncword */
-  mad_bit_skip(&stream->ptr, 11);
-
-  /* MPEG 2.5 indicator (really part of syncword) */
-  if (mad_bit_read(&stream->ptr, 1) == 0)
-    header->flags |= MAD_FLAG_MPEG_2_5_EXT;
-
-  /* ID */
-  if (mad_bit_read(&stream->ptr, 1) == 0)
-    header->flags |= MAD_FLAG_LSF_EXT;
-  else if (header->flags & MAD_FLAG_MPEG_2_5_EXT) {
-    stream->error = MAD_ERROR_LOSTSYNC;
-    return -1;
-  }
-
-  /* layer */
-  header->layer = (enum mad_layer)(4 - mad_bit_read(&stream->ptr, 2));
-
-  if (header->layer == 4) {
-    stream->error = MAD_ERROR_BADLAYER;
-    return -1;
-  }
-
-  /* protection_bit */
-  if (mad_bit_read(&stream->ptr, 1) == 0) {
-    header->flags    |= MAD_FLAG_PROTECTION;
-    header->crc_check = mad_bit_crc(stream->ptr, 16, 0xffff);
-  }
-
-  /* bitrate_index */
-  index = mad_bit_read(&stream->ptr, 4);
-
-  if (index == 15) {
-    stream->error = MAD_ERROR_BADBITRATE;
-    return -1;
-  }
-
-  if (header->flags & MAD_FLAG_LSF_EXT)
-    header->bitrate = bitrate_table[3 + (header->layer >> 1)][index];
-  else
-    header->bitrate = bitrate_table[header->layer - 1][index];
-
-  /* sampling_frequency */
-  index = mad_bit_read(&stream->ptr, 2);
-
-  if (index == 3) {
-    stream->error = MAD_ERROR_BADSAMPLERATE;
-    return -1;
-  }
-
-  header->samplerate = samplerate_table[index];
-
-  if (header->flags & MAD_FLAG_LSF_EXT) {
-    header->samplerate /= 2;
-
-    if (header->flags & MAD_FLAG_MPEG_2_5_EXT)
-      header->samplerate /= 2;
-  }
-
-  /* padding_bit */
-  if (mad_bit_read(&stream->ptr, 1))
-    header->flags |= MAD_FLAG_PADDING;
-
-  /* private_bit */
-  if (mad_bit_read(&stream->ptr, 1))
-    header->private_bits |= MAD_PRIVATE_HEADER;
-
-  /* mode */
-  header->mode = (enum mad_mode)(3 - mad_bit_read(&stream->ptr, 2));
-
-  /* mode_extension */
-  header->mode_extension = mad_bit_read(&stream->ptr, 2);
-
-  /* copyright */
-  if (mad_bit_read(&stream->ptr, 1))
-    header->flags |= MAD_FLAG_COPYRIGHT;
-
-  /* original/copy */
-  if (mad_bit_read(&stream->ptr, 1))
-    header->flags |= MAD_FLAG_ORIGINAL;
-
-  /* emphasis */
-  header->emphasis = (enum mad_emphasis)mad_bit_read(&stream->ptr, 2);
-
-# if defined(OPT_STRICT)
-  /*
-   * ISO/IEC 11172-3 says this is a reserved emphasis value, but
-   * streams exist which use it anyway. Since the value is not important
-   * to the decoder proper, we allow it unless OPT_STRICT is defined.
-   */
-  if (header->emphasis == MAD_EMPHASIS_RESERVED) {
-    stream->error = MAD_ERROR_BADEMPHASIS;
-    return -1;
-  }
-# endif
-
-  /* error_check() */
-
-  /* crc_check */
-  if (header->flags & MAD_FLAG_PROTECTION)
-    header->crc_target = mad_bit_read(&stream->ptr, 16);
-
-  return 0;
-}
-
-/*
- * NAME:	free_bitrate()
- * DESCRIPTION:	attempt to discover the bitstream's free bitrate
- */
-static
-int free_bitrate(struct mad_stream *stream, struct mad_header const *header)
-{
-  struct mad_bitptr keep_ptr;
-  unsigned long rate = 0;
-  unsigned int pad_slot, slots_per_frame;
-  unsigned char const *ptr = 0;
-
-  keep_ptr = stream->ptr;
-
-  pad_slot = (header->flags & MAD_FLAG_PADDING) ? 1 : 0;
-  slots_per_frame = (header->layer == MAD_LAYER_III &&
-		     (header->flags & MAD_FLAG_LSF_EXT)) ? 72 : 144;
-
-  while (mad_stream_sync(stream) == 0) {
-    struct mad_stream peek_stream;
-    struct mad_header peek_header;
-
-    peek_stream = *stream;
-    peek_header = *header;
-
-    if (decode_header(&peek_header, &peek_stream) == 0 &&
-	peek_header.layer == header->layer &&
-	peek_header.samplerate == header->samplerate) {
-      unsigned int N;
-
-      ptr = mad_bit_nextbyte(&stream->ptr);
-
-      N = ptr - stream->this_frame;
-
-      if (header->layer == MAD_LAYER_I) {
-	rate = (unsigned long) header->samplerate *
-	  (N - 4 * pad_slot + 4) / 48 / 1000;
-      }
-      else {
-	rate = (unsigned long) header->samplerate *
-	  (N - pad_slot + 1) / slots_per_frame / 1000;
-      }
-
-      if (rate >= 8)
-	break;
-    }
-
-    mad_bit_skip(&stream->ptr, 8);
-  }
-
-  stream->ptr = keep_ptr;
-
-  if (rate < 8 || (header->layer == MAD_LAYER_III && rate > 640)) {
-    stream->error = MAD_ERROR_LOSTSYNC;
-    return -1;
-  }
-
-  stream->freerate = rate * 1000;
-
-  return 0;
-}
-
-/*
- * NAME:	header->decode()
- * DESCRIPTION:	read the next frame header from the stream
- */
-int mad_header_decode(struct mad_header *header, struct mad_stream *stream)
-{
-  register unsigned char const *ptr, *end;
-  unsigned int pad_slot, N;
-
-  ptr = stream->next_frame;
-  end = stream->bufend;
-
-  if (ptr == 0) {
-    stream->error = MAD_ERROR_BUFPTR;
-    goto fail;
-  }
-
-  /* stream skip */
-  if (stream->skiplen) {
-    if (!stream->sync)
-      ptr = stream->this_frame;
-
-    if (end - ptr < stream->skiplen) {
-      stream->skiplen   -= end - ptr;
-      stream->next_frame = end;
-
-      stream->error = MAD_ERROR_BUFLEN;
-      goto fail;
-    }
-
-    ptr += stream->skiplen;
-    stream->skiplen = 0;
-
-    stream->sync = 1;
-  }
-
- sync:
-  /* synchronize */
-  if (stream->sync) {
-    if (end - ptr < MAD_BUFFER_GUARD) {
-      stream->next_frame = ptr;
-
-      stream->error = MAD_ERROR_BUFLEN;
-      goto fail;
-    }
-    else if (!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0)) {
-      /* mark point where frame sync word was expected */
-      stream->this_frame = ptr;
-      stream->next_frame = ptr + 1;
-
-      stream->error = MAD_ERROR_LOSTSYNC;
-      goto fail;
-    }
-  }
-  else {
-    mad_bit_init(&stream->ptr, ptr);
-
-    if (mad_stream_sync(stream) == -1) {
-      if (end - stream->next_frame >= MAD_BUFFER_GUARD)
-	stream->next_frame = end - MAD_BUFFER_GUARD;
-
-      stream->error = MAD_ERROR_BUFLEN;
-      goto fail;
-    }
-
-    ptr = mad_bit_nextbyte(&stream->ptr);
-  }
-
-  /* begin processing */
-  stream->this_frame = ptr;
-  stream->next_frame = ptr + 1;  /* possibly bogus sync word */
-
-  mad_bit_init(&stream->ptr, stream->this_frame);
-
-  if (decode_header(header, stream) == -1)
-    goto fail;
-
-  /* calculate frame duration */
-  mad_timer_set(&header->duration, 0,
-		32 * MAD_NSBSAMPLES(header), header->samplerate);
-
-  /* calculate free bit rate */
-  if (header->bitrate == 0) {
-    if ((stream->freerate == 0 || !stream->sync ||
-	 (header->layer == MAD_LAYER_III && stream->freerate > 640000)) &&
-	free_bitrate(stream, header) == -1)
-      goto fail;
-
-    header->bitrate = stream->freerate;
-    header->flags  |= MAD_FLAG_FREEFORMAT;
-  }
-
-  /* calculate beginning of next frame */
-  pad_slot = (header->flags & MAD_FLAG_PADDING) ? 1 : 0;
-
-  if (header->layer == MAD_LAYER_I)
-    N = ((12 * header->bitrate / header->samplerate) + pad_slot) * 4;
-  else {
-    unsigned int slots_per_frame;
-
-    slots_per_frame = (header->layer == MAD_LAYER_III &&
-		       (header->flags & MAD_FLAG_LSF_EXT)) ? 72 : 144;
-
-    N = (slots_per_frame * header->bitrate / header->samplerate) + pad_slot;
-  }
-
-  /* verify there is enough data left in buffer to decode this frame */
-  if (N + MAD_BUFFER_GUARD > end - stream->this_frame) {
-    stream->next_frame = stream->this_frame;
-
-    stream->error = MAD_ERROR_BUFLEN;
-    goto fail;
-  }
-
-  stream->next_frame = stream->this_frame + N;
-
-  if (!stream->sync) {
-    /* check that a valid frame header follows this frame */
-
-    ptr = stream->next_frame;
-    if (!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0)) {
-      ptr = stream->next_frame = stream->this_frame + 1;
-      goto sync;
-    }
-
-    stream->sync = 1;
-  }
-
-  header->flags |= MAD_FLAG_INCOMPLETE;
-
-  return 0;
-
- fail:
-  stream->sync = 0;
-
-  return -1;
-}
-
-/*
- * NAME:	frame->decode()
- * DESCRIPTION:	decode a single frame from a bitstream
- */
-int mad_frame_decode(struct mad_frame *frame, struct mad_stream *stream)
-{
-  frame->options = stream->options;
-
-  /* header() */
-  /* error_check() */
-
-  if (!(frame->header.flags & MAD_FLAG_INCOMPLETE) &&
-      mad_header_decode(&frame->header, stream) == -1)
-    goto fail;
-
-  /* audio_data() */
-
-  frame->header.flags &= ~MAD_FLAG_INCOMPLETE;
-
-  if (decoder_table[frame->header.layer - 1](stream, frame) == -1) {
-    if (!MAD_RECOVERABLE(stream->error))
-      stream->next_frame = stream->this_frame;
-
-    goto fail;
-  }
-
-  /* ancillary_data() */
-
-  if (frame->header.layer != MAD_LAYER_III) {
-    struct mad_bitptr next_frame;
-
-    mad_bit_init(&next_frame, stream->next_frame);
-
-    stream->anc_ptr    = stream->ptr;
-    stream->anc_bitlen = mad_bit_length(&stream->ptr, &next_frame);
-
-    mad_bit_finish(&next_frame);
-  }
-
-  return 0;
-
- fail:
-  stream->anc_bitlen = 0;
-  return -1;
-}
-
-/*
- * NAME:	frame->mute()
- * DESCRIPTION:	zero all subband values so the frame becomes silent
- */
-void mad_frame_mute(struct mad_frame *frame)
-{
-  unsigned int s, sb;
-
-  for (s = 0; s < 36; ++s) {
-    for (sb = 0; sb < 32; ++sb) {
-      frame->sbsample[0][s][sb] =
-      frame->sbsample[1][s][sb] = 0;
-    }
-  }
-
-  if (frame->overlap) {
-    for (s = 0; s < 18; ++s) {
-      for (sb = 0; sb < 32; ++sb) {
-	(frame->overlap)[0][sb][s] =
-	(frame->overlap)[1][sb][s] = 0;
-      }
-    }
-  }
-}