demux_real.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

/*
    Real parser & demuxer
    
    (C) Alex Beregszaszi
    
    Based on FFmpeg's libav/rm.c.

Audio codecs: (supported by RealPlayer8 for Linux)
    DNET - RealAudio 3.0, really it's AC3 in swapped-byteorder
    SIPR - SiproLab's audio codec, ACELP decoder working with MPlayer,
	   needs fine-tuning too :)
    ATRC - RealAudio 8 (ATRAC3) - www.minidisc.org/atrac3_article.pdf,
           ACM decoder uploaded, needs some fine-tuning to work
	   -> RealAudio 8
    COOK/COKR - Real Cooker -> RealAudio G2

Video codecs: (supported by RealPlayer8 for Linux)
    RV10 - H.263 based, working with libavcodec's decoder
    RV20-RV40 - using RealPlayer's codec plugins
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

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

#include "stream.h"
#include "demuxer.h"
#include "stheader.h"
#include "bswap.h"

//#define mp_dbg(mod,lev, args... ) mp_msg_c((mod<<8)|lev, ## args )

#define MKTAG(a, b, c, d) (a | (b << 8) | (c << 16) | (d << 24))

#define MAX_STREAMS 32

typedef struct {
    int		timestamp;
    int		offset;
//    int		packetno;
//    int		len; /* only filled by our index generator */
//    int		flags; /* only filled by our index generator */
} real_index_table_t;

typedef struct {
    /* for seeking */
    int		index_chunk_offset;
    real_index_table_t *index_table[MAX_STREAMS];
	
//    int		*index_table[MAX_STREAMS];
    int		index_table_size[MAX_STREAMS];
    int		index_malloc_size[MAX_STREAMS];
    int		data_chunk_offset;
    int		num_of_packets;
    int		current_packet;
	
// need for seek
    int		audio_need_keyframe;
    int		video_after_seek;

    int		current_apacket;
    int		current_vpacket;
    
    // timestamp correction:
    int		kf_base;// timestamp of the prev. video keyframe
    int		kf_pts;	// timestamp of next video keyframe
    int		a_pts;	// previous audio timestamp
    float	v_pts;  // previous video timestamp
    unsigned long	duration;
    
    /* stream id table */
//    int		last_a_stream;
//    int 	a_streams[MAX_STREAMS];
//    int		last_v_stream;
//    int 	v_streams[MAX_STREAMS];

    /**
     * Used to demux multirate files
     */
    int is_multirate; ///< != 0 for multirate files
    int str_data_offset[MAX_STREAMS]; ///< Data chunk offset for every audio/video stream
    int audio_curpos; ///< Current file position for audio demuxing
    int video_curpos; ///< Current file position for video demuxing
    int a_num_of_packets; ///< Number of audio packets
    int v_num_of_packets; ///< Number of video packets
    int a_idx_ptr; ///< Audio index position pointer
    int v_idx_ptr; ///< Video index position pointer
    int a_bitrate; ///< Audio bitrate
    int v_bitrate; ///< Video bitrate
    int stream_switch; ///< Flag used to switch audio/video demuxing
} real_priv_t;

/* originally from FFmpeg */
static void get_str(int isbyte, demuxer_t *demuxer, char *buf, int buf_size)
{
    int len;
    
    if (isbyte)
	len = stream_read_char(demuxer->stream);
    else
	len = stream_read_word(demuxer->stream);

    stream_read(demuxer->stream, buf, (len > buf_size) ? buf_size : len);
    if (len > buf_size)
	stream_skip(demuxer->stream, len-buf_size);

    mp_msg(MSGT_DEMUX, MSGL_V, "read_str: %d bytes read\n", len);
}

static void skip_str(int isbyte, demuxer_t *demuxer)
{
    int len;

    if (isbyte)
	len = stream_read_char(demuxer->stream);
    else
	len = stream_read_word(demuxer->stream);

    stream_skip(demuxer->stream, len);    

    mp_msg(MSGT_DEMUX, MSGL_V, "skip_str: %d bytes skipped\n", len);
}

static void dump_index(demuxer_t *demuxer, int stream_id)
{
    real_priv_t *priv = demuxer->priv;
    real_index_table_t *index;
    int i, entries;

    if (verbose<=1)
	return;
    
    if (stream_id > MAX_STREAMS)
	return;

    index = priv->index_table[stream_id];
    entries = priv->index_table_size[stream_id];
    
    mp_msg(MSGT_DEMUX, MSGL_V, "Index table for stream %d\n", stream_id);
    for (i = 0; i < entries; i++)
    {
#if 1
	mp_msg(MSGT_DEMUX, MSGL_V,"i: %d, pos: %d, timestamp: %d\n", i, index[i].offset, index[i].timestamp);
#else
	mp_msg(MSGT_DEMUX, MSGL_V,"packetno: %x pos: %x len: %x timestamp: %x flags: %x\n",
	    index[i].packetno, index[i].offset, index[i].len, index[i].timestamp,
	    index[i].flags);
#endif
    }
}

static int parse_index_chunk(demuxer_t *demuxer)
{
    real_priv_t *priv = demuxer->priv;
    int origpos = stream_tell(demuxer->stream);
    int next_header_pos = priv->index_chunk_offset;
    int i, entries, stream_id;

read_index:
    stream_seek(demuxer->stream, next_header_pos);

    i = stream_read_dword_le(demuxer->stream);
    if ((i == -256) || (i != MKTAG('I', 'N', 'D', 'X')))
    {
	mp_msg(MSGT_DEMUX, MSGL_WARN,"Something went wrong, no index chunk found on given address (%d)\n",
	    next_header_pos);
	index_mode = -1;
        if (i == -256)
	    stream_reset(demuxer->stream);
    	stream_seek(demuxer->stream, origpos);
	return 0;
	//goto end;
    }

    mp_msg(MSGT_DEMUX, MSGL_V,"Reading index table from index chunk (%d)\n",
	next_header_pos);

    i = stream_read_dword(demuxer->stream);
    mp_msg(MSGT_DEMUX, MSGL_V,"size: %d bytes\n", i);

    i = stream_read_word(demuxer->stream);
    if (i != 0)
	mp_msg(MSGT_DEMUX, MSGL_WARN,"Hmm, index table with unknown version (%d), please report it to MPlayer developers!\n", i);

    entries = stream_read_dword(demuxer->stream);
    mp_msg(MSGT_DEMUX, MSGL_V,"entries: %d\n", entries);
    
    stream_id = stream_read_word(demuxer->stream);
    mp_msg(MSGT_DEMUX, MSGL_V,"stream_id: %d\n", stream_id);
    
    next_header_pos = stream_read_dword(demuxer->stream);
    mp_msg(MSGT_DEMUX, MSGL_V,"next_header_pos: %d\n", next_header_pos);
    if (entries <= 0)
    {
	if (next_header_pos)
	    goto read_index;
	i = entries;
	goto end;
    }

    priv->index_table_size[stream_id] = entries;
    priv->index_table[stream_id] = malloc(priv->index_table_size[stream_id] * sizeof(real_index_table_t));
    
    for (i = 0; i < entries; i++)
    {
	stream_skip(demuxer->stream, 2); /* version */
	priv->index_table[stream_id][i].timestamp = stream_read_dword(demuxer->stream);
	priv->index_table[stream_id][i].offset = stream_read_dword(demuxer->stream);
	stream_skip(demuxer->stream, 4); /* packetno */
//	priv->index_table[stream_id][i].packetno = stream_read_dword(demuxer->stream);
//	printf("Index table: Stream#%d: entry: %d: pos: %d\n",
//	    stream_id, i, priv->index_table[stream_id][i].offset);
    }
    
    dump_index(demuxer, stream_id);

    if (next_header_pos > 0)
	goto read_index;

end:
    if (i == -256)
	stream_reset(demuxer->stream);
    stream_seek(demuxer->stream, origpos);
    if (i == -256)
	return 0;
    else
	return 1;
}

#if 1

static void add_index_item(demuxer_t *demuxer, int stream_id, int timestamp, int offset)
{
  if ((unsigned)stream_id < MAX_STREAMS)
  {
    real_priv_t *priv = demuxer->priv;
    real_index_table_t *index;
    if (priv->index_table_size[stream_id] >= priv->index_malloc_size[stream_id])
    {
      if (priv->index_malloc_size[stream_id] == 0)
	priv->index_malloc_size[stream_id] = 2048;
      else
	priv->index_malloc_size[stream_id] += priv->index_malloc_size[stream_id] / 2;
      // in case we have a really large chunk...
      if (priv->index_table_size[stream_id] >=
            priv->index_malloc_size[stream_id])
        priv->index_malloc_size[stream_id] =
          priv->index_table_size[stream_id] + 1;
      priv->index_table[stream_id] = realloc(priv->index_table[stream_id], priv->index_malloc_size[stream_id]*sizeof(priv->index_table[0][0]));
    }
    if (priv->index_table_size[stream_id] > 0)
    {
      index = &priv->index_table[stream_id][priv->index_table_size[stream_id] - 1];
      if (index->timestamp >= timestamp || index->offset >= offset)
	return;
    }
    index = &priv->index_table[stream_id][priv->index_table_size[stream_id]++];
    index->timestamp = timestamp;
    index->offset = offset;
  }
}

static void add_index_segment(demuxer_t *demuxer, int seek_stream_id, int seek_timestamp)
{
  int tag, len, stream_id, timestamp, flags;
  if (seek_timestamp != -1 && (unsigned)seek_stream_id >= MAX_STREAMS)
    return;
  while (1)
  {
    demuxer->filepos = stream_tell(demuxer->stream);
    
    tag = stream_read_dword(demuxer->stream);
    if (tag == MKTAG('A', 'T', 'A', 'D'))
    {
      stream_skip(demuxer->stream, 14);
      continue; /* skip to next loop */
    }
    len = tag & 0xffff;
    if (tag == -256 || len < 12)
      break;
    
    stream_id = stream_read_word(demuxer->stream);
    timestamp = stream_read_dword(demuxer->stream);
    
    stream_skip(demuxer->stream, 1); /* reserved */
    flags = stream_read_char(demuxer->stream);
    
    if (flags == -256)
      break;
    
    if (flags & 2)
    {
      add_index_item(demuxer, stream_id, timestamp, demuxer->filepos);
      if (stream_id == seek_stream_id && timestamp >= seek_timestamp)
      {
	stream_seek(demuxer->stream, demuxer->filepos);
	return;
      }
    }
    // printf("Index: stream=%d packet=%d timestamp=%d len=%d flags=0x%x datapos=0x%x\n", stream_id, entries, timestamp, len, flags, index->offset);
    /* skip data */
    stream_skip(demuxer->stream, len-12);
  }
}

static int generate_index(demuxer_t *demuxer)
{
  real_priv_t *priv = demuxer->priv;
  int origpos = stream_tell(demuxer->stream);
  int data_pos = priv->data_chunk_offset-10;
  int i;
  int tag;
  
  stream_seek(demuxer->stream, data_pos);
  tag = stream_read_dword(demuxer->stream);
  if (tag != MKTAG('A', 'T', 'A', 'D'))
  {
    mp_msg(MSGT_DEMUX, MSGL_WARN,"Something went wrong, no data chunk found on given address (%d)\n", data_pos);
  }
  else
  {
    stream_skip(demuxer->stream, 14);
    add_index_segment(demuxer, -1, -1);
  }
  for (i = 0; i < MAX_STREAMS; i++)
  {
    if (priv->index_table_size[i] > 0)
    {
      dump_index(demuxer, i);
    }
  }
  stream_reset(demuxer->stream);
  stream_seek(demuxer->stream, origpos);
  return 0;
}

#else

static int generate_index(demuxer_t *demuxer)
{
    real_priv_t *priv = demuxer->priv;
    int origpos = stream_tell(demuxer->stream);
    int data_pos = priv->data_chunk_offset-10;
    int num_of_packets = 0;
    int i, entries = 0;
    int len, stream_id = 0, timestamp, flags;
    int tab_pos = 0;

read_index:
    stream_seek(demuxer->stream, data_pos);

    i = stream_read_dword_le(demuxer->stream);
    if ((i == -256) || (i != MKTAG('D', 'A', 'T', 'A')))
    {
	mp_msg(MSGT_DEMUX, MSGL_WARN,"Something went wrong, no data chunk found on given address (%d)\n",
	    data_pos);
	goto end;
    }
    stream_skip(demuxer->stream, 4); /* chunk size */
    stream_skip(demuxer->stream, 2); /* version */
    
    num_of_packets = stream_read_dword(demuxer->stream);
    mp_msg(MSGT_DEMUX, MSGL_V,"Generating index table from raw data (pos: 0x%x) for %d packets\n",
	data_pos, num_of_packets);

    data_pos = stream_read_dword_le(demuxer->stream)-10; /* next data chunk */

    for (i = 0; i < MAX_STREAMS; i++)
    {
    priv->index_table_size[i] = num_of_packets;
    priv->index_table[i] = malloc(priv->index_table_size[i] * sizeof(real_index_table_t));