demux_audio.c

来自「君正早期ucos系统(只有早期的才不没有打包成库),MPLAYER,文件系统,图」· C语言 代码 · 共 796 行 · 第 1/2 页

#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"

#include <mplaylib.h>
#include <mplaylib.h>
#include "stream/stream.h"
#include "demuxer.h"
#include "stheader.h"
#include "genres.h"
#include "mp3_hdr.h"
#include "libavutil/intreadwrite.h"

#include <mplaylib.h>
#undef memcpy
#define memcpy uc_memcpy
#define MP3 1
#define WAV 2
#define fLaC 3


#define HDR_SIZE 4

typedef struct da_priv {
  int frmt;
  double next_pts;
} da_priv_t;

//! rather arbitrary value for maximum length of wav-format headers
#define MAX_WAVHDR_LEN (1 * 1024 * 1024)

//! how many valid frames in a row we need before accepting as valid MP3
#define MIN_MP3_HDRS 12

//! Used to describe a potential (chain of) MP3 headers we found
typedef struct mp3_hdr {
  off_t frame_pos; // start of first frame in this "chain" of headers
  off_t next_frame_pos; // here we expect the next header with same parameters
  int mp3_chans;
  int mp3_freq;
  int mpa_spf;
  int mpa_layer;
  int mpa_br;
  int cons_hdrs; // if this reaches MIN_MP3_HDRS we accept as MP3 file
  struct mp3_hdr *next;
} mp3_hdr_t;

extern void print_wave_header(WAVEFORMATEX *h, int verbose_level);

int hr_mp3_seek = 1;
static float mp3_totaltime = 0;
/**
 * \brief free a list of MP3 header descriptions
 * \param list pointer to the head-of-list pointer
 */
static void free_mp3_hdrs(mp3_hdr_t **list) {
  mp3_hdr_t *tmp;
  while (*list) {
    tmp = (*list)->next;
    free(*list);
    *list = tmp;
  }
}

/**
 * \brief add another potential MP3 header to our list
 * If it fits into an existing chain this one is expanded otherwise
 * a new one is created.
 * All entries that expected a MP3 header before the current position
 * are discarded.
 * The list is expected to be and will be kept sorted by next_frame_pos
 * and when those are equal by frame_pos.
 * \param list pointer to the head-of-list pointer
 * \param st_pos stream position where the described header starts
 * \param mp3_chans number of channels as specified by the header (*)
 * \param mp3_freq sampling frequency as specified by the header (*)
 * \param mpa_spf frame size as specified by the header
 * \param mpa_layer layer type ("version") as specified by the header (*)
 * \param mpa_br bitrate as specified by the header
 * \param mp3_flen length of the frame as specified by the header
 * \return If non-null the current file is accepted as MP3 and the
 * mp3_hdr struct describing the valid chain is returned. Must be
 * freed independent of the list.
 *
 * parameters marked by (*) must be the same for all headers in the same chain
 */
static mp3_hdr_t *add_mp3_hdr(mp3_hdr_t **list, off_t st_pos,
                               int mp3_chans, int mp3_freq, int mpa_spf,
                               int mpa_layer, int mpa_br, int mp3_flen) {
  mp3_hdr_t *tmp;
  int in_list = 0;
  while (*list && (*list)->next_frame_pos <= st_pos) {
    if (((*list)->next_frame_pos < st_pos) || ((*list)->mp3_chans != mp3_chans)
         || ((*list)->mp3_freq != mp3_freq) || ((*list)->mpa_layer != mpa_layer) ) {
      // wasn't valid!
      tmp = (*list)->next;
      free(*list);
      *list = tmp;
    } else {
      (*list)->cons_hdrs++;
      (*list)->next_frame_pos = st_pos + mp3_flen;
      (*list)->mpa_spf = mpa_spf;
      (*list)->mpa_br = mpa_br;
      if ((*list)->cons_hdrs >= MIN_MP3_HDRS) {
        // copy the valid entry, so that the list can be easily freed
        tmp = malloc(sizeof(mp3_hdr_t));
        memcpy(tmp, *list, sizeof(mp3_hdr_t));
        tmp->next = NULL;
        return tmp;
      }
      in_list = 1;
      list = &((*list)->next);
    }
  }
  if (!in_list) { // does not belong into an existing chain, insert
    // find right position to insert to keep sorting
    while (*list && (*list)->next_frame_pos <= st_pos + mp3_flen)
      list = &((*list)->next);
    tmp = malloc(sizeof(mp3_hdr_t));
    tmp->frame_pos = st_pos;
    tmp->next_frame_pos = st_pos + mp3_flen;
    tmp->mp3_chans = mp3_chans;
    tmp->mp3_freq = mp3_freq;
    tmp->mpa_spf = mpa_spf;
    tmp->mpa_layer = mpa_layer;
    tmp->mpa_br = mpa_br;
    tmp->cons_hdrs = 1;
    tmp->next = *list;
    *list = tmp;
  }
  return NULL;
}

#define FLAC_SIGNATURE_SIZE 4
#define FLAC_STREAMINFO_SIZE 34
#define FLAC_SEEKPOINT_SIZE 18

enum {
  FLAC_STREAMINFO = 0,
  FLAC_PADDING,
  FLAC_APPLICATION,
  FLAC_SEEKTABLE,
  FLAC_VORBIS_COMMENT,
  FLAC_CUESHEET
} flac_preamble_t;

static void
get_flac_metadata (demuxer_t* demuxer)
{
  uint8_t preamble[4];
  unsigned int blk_len;
  stream_t *s = NULL;

  if (!demuxer)
    return;

  s = demuxer->stream;
  if (!s)
    return;
  
  /* file is qualified; skip over the signature bytes in the stream */
  stream_seek (s, 4);

  /* loop through the metadata blocks; use a do-while construct since there
   * will always be 1 metadata block */
  do {
    int r;
    
    r = stream_read (s, (char *) preamble, FLAC_SIGNATURE_SIZE);
    if (r != FLAC_SIGNATURE_SIZE)
      return;

    blk_len = (preamble[1] << 16) | (preamble[2] << 8) | (preamble[3] << 0);

    switch (preamble[0] & 0x7F)
    {
    case FLAC_STREAMINFO:
    {
      if (blk_len != FLAC_STREAMINFO_SIZE)
        return;

      stream_skip (s, FLAC_STREAMINFO_SIZE);
      break;
    }

    case FLAC_PADDING:
      stream_skip (s, blk_len);
      break;

    case FLAC_APPLICATION:
      stream_skip (s, blk_len);
      break;

    case FLAC_SEEKTABLE:
    {
      int seekpoint_count, i;

      seekpoint_count = blk_len / FLAC_SEEKPOINT_SIZE;
      for (i = 0; i < seekpoint_count; i++)
        if (stream_skip (s, FLAC_SEEKPOINT_SIZE) != 1)
          return;
      break;
    }

    case FLAC_VORBIS_COMMENT:
    {
      /* For a description of the format please have a look at */
      /* http://www.xiph.org/vorbis/doc/v-comment.html */

      uint32_t length, comment_list_len;
      char comments[blk_len];
      uint8_t *ptr = comments;
      char *comment;
      int cn;
      char c;

      if (stream_read (s, comments, blk_len) == blk_len)
      {
        length = AV_RL32(ptr);
        ptr += 4 + length;

        comment_list_len = AV_RL32(ptr);
        ptr += 4;

        cn = 0;
        for (; cn < comment_list_len; cn++)
        {
          length = AV_RL32(ptr);
          ptr += 4;

          comment = ptr;
          c = comment[length];
          comment[length] = 0;

          if (!strncasecmp ("TITLE=", comment, 6) && (length - 6 > 0))
            demux_info_add (demuxer, "Title", comment + 6);
          else if (!strncasecmp ("ARTIST=", comment, 7) && (length - 7 > 0))
            demux_info_add (demuxer, "Artist", comment + 7);
          else if (!strncasecmp ("ALBUM=", comment, 6) && (length - 6 > 0))
            demux_info_add (demuxer, "Album", comment + 6);
          else if (!strncasecmp ("DATE=", comment, 5) && (length - 5 > 0))
            demux_info_add (demuxer, "Year", comment + 5);
          else if (!strncasecmp ("GENRE=", comment, 6) && (length - 6 > 0))
            demux_info_add (demuxer, "Genre", comment + 6);
          else if (!strncasecmp ("Comment=", comment, 8) && (length - 8 > 0))
            demux_info_add (demuxer, "Comment", comment + 8);
          else if (!strncasecmp ("TRACKNUMBER=", comment, 12)
                   && (length - 12 > 0))
          {
            char buf[31];
            buf[30] = '\0';
            sprintf (buf, "%d", atoi (comment + 12));
            demux_info_add(demuxer, "Track", buf);
          }
          comment[length] = c;

          ptr += length;
        }
      }
      break;
    }

    case FLAC_CUESHEET:
      stream_skip (s, blk_len);
      break;

    default: 
      /* 6-127 are presently reserved */
      stream_skip (s, blk_len);
      break;
    }
  } while ((preamble[0] & 0x80) == 0);
}
static uint32_t mp3_total_framecount(demuxer_t* demuxer)
{
	uint8_t hdr[4];
  int len;
  int count = 0;
  uint32_t pos_start;
  int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
  stream_t* s = demuxer->stream;
  pos_start = stream_tell(s);
  while(s->eof == 0) {
    stream_read(demuxer->stream,hdr,4);
    if (s->eof)
    {
    	 break;
    }
    len = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
                                &mpa_spf, &mpa_layer, &mpa_br);
    if(len < 0) {
      stream_skip(demuxer->stream,-3);
      continue;
    }
    if (s->eof)
    {
    	break;
    	
    }
    stream_skip(demuxer->stream,len-4);
    
    if(stream_tell(s) >= s->end_pos-128-len)
    	break;
    count++;
  }
	s->eof = 0;  
  return count;
}
static int demux_audio_open(demuxer_t* demuxer) {
  stream_t *s;
  sh_audio_t* sh_audio;
  uint8_t hdr[HDR_SIZE];
  int frmt = 0, n = 0, step;
  off_t st_pos = 0, next_frame_pos = 0;
  // mp3_hdrs list is sorted first by next_frame_pos and then by frame_pos
  mp3_hdr_t *mp3_hdrs = NULL, *mp3_found = NULL;
  da_priv_t* priv;
  
  s = demuxer->stream;

  stream_read(s, hdr, HDR_SIZE);
  while(n < 30000 && !s->eof) {
    int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
    st_pos = stream_tell(s) - HDR_SIZE;
    step = 1;

    if( hdr[0] == 'R' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == 'F' ) {
      stream_skip(s,4);
      if(s->eof)
	break;
      stream_read(s,hdr,4);
      if(s->eof)
	break;
      if(hdr[0] != 'W' || hdr[1] != 'A' || hdr[2] != 'V'  || hdr[3] != 'E' )
	stream_skip(s,-8);
      else
      // We found wav header. Now we can have 'fmt ' or a mp3 header
      // empty the buffer
	step = 4;
    } else if( hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3' && (hdr[3] >= 2)) {
      int len;
      stream_skip(s,2);
      stream_read(s,hdr,4);
      len = (hdr[0]<<21) | (hdr[1]<<14) | (hdr[2]<<7) | hdr[3];
      stream_skip(s,len);
      step = 4;
    } else if( hdr[0] == 'f' && hdr[1] == 'm' && hdr[2] == 't' && hdr[3] == ' ' ) {
      frmt = WAV;
      break;      
    } else if((mp3_flen = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
                                &mpa_spf, &mpa_layer, &mpa_br)) > 0) {
      mp3_found = add_mp3_hdr(&mp3_hdrs, st_pos, mp3_chans, mp3_freq,
                              mpa_spf, mpa_layer, mpa_br, mp3_flen);
      if (mp3_found) {
        frmt = MP3;
        break;
      }
    } else if( hdr[0] == 'f' && hdr[1] == 'L' && hdr[2] == 'a' && hdr[3] == 'C' ) {
      frmt = fLaC;
      break;
    }
    // Add here some other audio format detection
    if(step < HDR_SIZE)
      memmove(hdr,&hdr[step],HDR_SIZE-step);
    stream_read(s, &hdr[HDR_SIZE - step], step);
    n++;
  }

  free_mp3_hdrs(&mp3_hdrs);

  if(!frmt)
    return 0;

  sh_audio = new_sh_audio(demuxer,0);

  switch(frmt) {
  case MP3:
    sh_audio->format = (mp3_found->mpa_layer < 3 ? 0x50 : 0x55);
    demuxer->movi_start = mp3_found->frame_pos;
    next_frame_pos = mp3_found->next_frame_pos;
    sh_audio->audio.dwSampleSize= 0;
    sh_audio->audio.dwScale = mp3_found->mpa_spf;
    sh_audio->audio.dwRate = mp3_found->mp3_freq;
    sh_audio->wf = malloc(sizeof(WAVEFORMATEX));
    sh_audio->wf->wFormatTag = sh_audio->format;
    sh_audio->wf->nChannels = mp3_found->mp3_chans;
    sh_audio->wf->nSamplesPerSec = mp3_found->mp3_freq;
    sh_audio->wf->nAvgBytesPerSec = mp3_found->mpa_br * (1000 / 8);
    sh_audio->wf->nBlockAlign = mp3_found->mpa_spf;
    sh_audio->wf->wBitsPerSample = 16;
    sh_audio->wf->cbSize = 0;    
    sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
    
      //F("get totla time %d %d\n",sh_audio->audio.dwRate,sh_audio->wf->nBlockAlign);
      int dcount = mp3_total_framecount(demuxer);
      
     mp3_totaltime = (float)(dcount * sh_audio->wf->nBlockAlign / sh_audio->audio.dwRate);