<?php

/*
* qtfaststart.php v0.1 by Valentin Schmidt
* based on qt-faststart.c v0.2 by Mike Melanson (melanson@pcisys.net)
*
* This file is placed in the public domain. Use the program however you
* see fit.
*
* This utility rearranges a Quicktime file such that the moov atom
* is in front of the data, thus facilitating network streaming.
*
* Notes: Quicktime files can come in many configurations of top-level
* atoms. This utility stipulates that the very last atom in the file needs
* to be a moov atom. When given such a file, this utility will rearrange
* the top-level atoms by shifting the moov atom from the back of the file
* to the front, and patch the chunk offsets along the way. This utility
* presently only operates on uncompressed moov atoms.
*/

define('MOOV_ATOM', 'moov');
define('FTYP_ATOM', 'ftyp');
define('CMOV_ATOM', 'cmov');
define('STCO_ATOM', 'stco');
define('CO64_ATOM', 'co64');

define('ATOM_PREAMBLE_SIZE', 8);
define('COPY_BUFFER_SIZE', 1024);

function
BE_32($x, $offset=0){
  return
    (ord($x[$offset+0]) << 24) |
    (ord($x[$offset+1]) << 16) |
    (ord($x[$offset+2]) << 8) |
    (ord($x[$offset+3]));
}

function
BE_64($x, $offset=0){
  return
    (ord($x[$offset+0]) << 56) |
    (ord($x[$offset+1]) << 48) |
    (ord($x[$offset+2]) << 40) |
    (ord($x[$offset+3]) << 32) |
    (ord($x[$offset+4]) << 24) |
    (ord($x[$offset+5]) << 16) |
    (ord($x[$offset+6]) << 8) |
    (ord($x[$offset+7]));
}

function
status($s){
  echo $s.'<br />';
}

function
qtfaststart($inputVideoFile, $outputVideoFile){

  $atom_offset = 0;
  $atom_type = '';

  $infile = fopen($inputVideoFile, "rb");
  if (!$infile) {
    return 0;
  }


/* traverse through the atoms in the file to make sure that 'moov' is at the end */
  while (!feof($infile)) {
    if (($atom_bytes = fread($infile, ATOM_PREAMBLE_SIZE)) == FALSE) {
      break;
    }

    $atom_size = BE_32($atom_bytes, 0);
    $atom_type = substr($atom_bytes, 4, 4);

    /* keep ftyp atom */
    if ($atom_type == FTYP_ATOM) {
      $ftyp_atom_size = $atom_size;
      fseek($infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR);
      $ftyp_atom = fread($infile, $ftyp_atom_size);
      $start_offset = ftell($infile);
    } else {
      /* 64-bit special case */
      if ($atom_size == 1) {
        if (($atom_bytes = fread($infile, ATOM_PREAMBLE_SIZE)) == FALSE) {
          break;
        }
        $atom_size = BE_64($atom_bytes, 0);
        fseek($infile, $atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
      } else {
        fseek($infile, $atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
      }
    }

    $atom_offset += $atom_size;


/* The atom header is 8 (or 16 bytes), if the atom size (which
     * includes these 8 or 16 bytes) is less than that, we won't be
     * able to continue scanning sensibly after this atom, so break. */
    if ($atom_size < 8) break;
  }

  if (
$atom_type != MOOV_ATOM) {
    status("last atom in file was not a moov atom");
    fclose($infile);
    return 0;
  }


/* moov atom was, in fact, the last atom in the chunk; load the whole moov atom */
  fseek($infile, -$atom_size, SEEK_END);
  $last_offset = ftell($infile);
  $moov_atom_size = $atom_size;
  if (($moov_atom = fread($infile, $moov_atom_size)) == FALSE) {
    fclose($infile);
    return 0;
  }


/* this utility does not support compressed atoms yet, so disqualify
   * files with compressed QT atoms */
  if (substr($moov_atom, 12, 4) == CMOV_ATOM) {
    status("this utility does not support compressed moov atoms yet");
    fclose($infile);
    return 0;
  }


/* close; will be re-opened later */
  fclose($infile);


/* crawl through the moov chunk in search of stco or co64 atoms */
  for ($i = 4; $i < $moov_atom_size - 4; $i++) {
    $atom_type = substr($moov_atom, $i, 4);

    if ($atom_type == STCO_ATOM) {
      status(" patching stco atom");
      $atom_size = BE_32($moov_atom, $i - 4);
      if ($i + $atom_size - 4 > $moov_atom_size) {
        status(" bad atom size");
        return 0;
      }
      $offset_count = BE_32($moov_atom, $i + 8);
      for ($j = 0; $j < $offset_count; $j++) {
        $current_offset = BE_32($moov_atom, $i + 12 + $j * 4);
        $current_offset += $moov_atom_size;
        $moov_atom[$i + 12 + $j * 4 + 0] = chr( ($current_offset >> 24) & 0xFF);
        $moov_atom[$i + 12 + $j * 4 + 1] = chr( ($current_offset >> 16) & 0xFF);
        $moov_atom[$i + 12 + $j * 4 + 2] = chr( ($current_offset >>  8) & 0xFF);
        $moov_atom[$i + 12 + $j * 4 + 3] = chr( ($current_offset >>  0) & 0xFF);
      }
      $i += $atom_size - 4;

    } else if ($atom_type == CO64_ATOM) {
      status(" patching co64 atom");
      $atom_size = BE_32($moov_atom, $i - 4);
      if ($i + $atom_size - 4 > $moov_atom_size) {
        status(" bad atom size");
        return 0;
      }
      $offset_count = BE_32($moov_atom, $i + 8);
      for ($j = 0; $j < $offset_count; $j++) {
        $current_offset = BE_64($moov_atom, $i + 12 + $j * 8);
        $current_offset += $moov_atom_size;
        $moov_atom[$i + 12 + $j * 8 + 0] = chr( ($current_offset >> 56) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 1] = chr( ($current_offset >> 48) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 2] = chr( ($current_offset >> 40) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 3] = chr( ($current_offset >> 32) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 4] = chr( ($current_offset >> 24) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 5] = chr( ($current_offset >> 16) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 6] = chr( ($current_offset >>  8) & 0xFF);
        $moov_atom[$i + 12 + $j * 8 + 7] = chr( ($current_offset >>  0) & 0xFF);
      }
      $i += $atom_size - 4;
    }
  }


/* re-open the input file and open the output file */
  $infile = fopen($inputVideoFile, "rb");
  if (!$infile) {
    return 0;
  }

  if (
$start_offset > 0) { /* seek after ftyp atom */
    fseek($infile, $start_offset, SEEK_SET);
    $last_offset -= $start_offset;
  }


$outfile = fopen($outputVideoFile, "wb");
  if (!$outfile) {
    fclose($infile);
    return 0;
  }


/* dump the same ftyp atom */
  if ($ftyp_atom_size > 0) {
    status(" writing ftyp atom");
    if ((fwrite($outfile, $ftyp_atom, $ftyp_atom_size)) == FALSE) {
      fclose($infile);
      fclose($outfile);
      return 0;
    }
  }


/* dump the new moov atom */
  status(" writing moov atom");
  if ((fwrite($outfile, $moov_atom, $moov_atom_size)) == FALSE) {
    fclose($infile);
    fclose($outfile);
    return 0;
  }


/* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
  status(" copying rest of file");
  while ($last_offset) {
    if ($last_offset > COPY_BUFFER_SIZE)
      $bytes_to_copy = COPY_BUFFER_SIZE;
    else
      $bytes_to_copy = $last_offset;
    if (($copy_buffer = fread($infile, $bytes_to_copy)) == FALSE) {
      fclose($infile);
      fclose($outfile);
      return 0;
    }
    if ((fwrite($outfile, $copy_buffer, $bytes_to_copy)) == FALSE) {
      fclose($infile);
      fclose($outfile);
      return 0;
    }
    $last_offset -= $bytes_to_copy;
  }


fclose($infile);
  fclose($outfile);
  return 1;
}

?>