/**
* Decomposes a file into flv tags while reading. Searches for keyframes
*
* @param string $filename
* @return Yamdi_InputStream
*/
protected function read($filename)
{
$stream = parent::read($filename);
$this->filepositions = array();
$this->times = array();
$tag = new Yamdi_FlvTag();
while (!$stream->isEnd()) {
$tag_position = $stream->getPosition();
/*
* Tag
*/
if (!$tag->read($stream)) {
break;
}
if (!$tag->isValid()) {
throw new Exception('Invalid tag found');
}
if ($tag->isVideo()) {
if ($tag->checkIfKeyFrame($stream)) {
$this->filepositions[] = $tag_position;
$this->times[] = $tag->getTimestamp() / 1000.0;
}
}
$tag->skipTagBody($stream);
// wind forward to next tag
/*
* Previous tag size
*/
$tagSize = new Yamdi_FlvTagSize();
if (!$tagSize->read($stream)) {
break;
}
}
return null;
//nothing else to read
}
/**
* Decomposes a file into flv tags while reading. Searches for given keyframe
*
* @param string $filename
* @return Yamdi_InputStream
*/
protected function read($filename)
{
$stream = parent::read($filename);
/*
* Looking for needed keyframe video tag
*/
if ($this->metadata->keyframes !== null) {
/*
* Keyframes present in meta, getting position of needed tag
*/
$filepositions = $this->metadata->keyframes->filepositions;
if (isset($filepositions[$this->desiredKeyframeNumber])) {
$this->videoTagPosition = $filepositions[$this->desiredKeyframeNumber];
} else {
$this->videoTagPosition = $filepositions[0];
}
/*
* Reading tag to fetch block size
*/
$stream->seek($this->videoTagPosition, SEEK_SET);
$tag = new Yamdi_FlvTag();
if (!$tag->read($stream)) {
throw new Exception('Invalid tag fileposition');
}
if (!$tag->isValid()) {
throw new Exception('Invalid tag found');
}
if (!$tag->isVideo()) {
throw new Exception('Specified tag is not video');
}
if (!$tag->checkIfKeyFrame($stream)) {
throw new Exception('Specified tag is not a keyframe');
}
$this->videoBlockSize = $tag->getDataSize() + 4 + 11;
} else {
/*
* Keyframes absent in meta, reading tags until needed keyframe is found
*/
$tag = new Yamdi_FlvTag();
$keyframe_number = 0;
while (!$stream->isEnd()) {
$tag_position = $stream->getPosition();
/*
* Tag
*/
if (!$tag->read($stream)) {
break;
}
if (!$tag->isValid()) {
throw new Exception('Invalid tag found');
}
if ($tag->isVideo()) {
if ($tag->checkIfKeyFrame($stream)) {
if ($this->videoTagPosition === null) {
// initializing with first tag position and size
$this->videoTagPosition = $tag_position;
$this->videoBlockSize = $tag->getDataSize() + 4 + 11;
}
if (++$keyframe_number == $this->desiredKeyframeNumber) {
$this->videoTagPosition = $tag_position;
//found keyframe
$this->videoBlockSize = $tag->getDataSize() + 4 + 11;
break;
}
}
}
$tag->skipTagBody($stream);
// wind forward to next tag
/*
* Previous tag size
*/
$tagSize = new Yamdi_FlvTagSize();
if (!$tagSize->read($stream)) {
break;
}
}
}
return null;
//nothing else to read
}
/**
* @deprecated
*/
public function testFileRead()
{
/*
* Here we need a real correct flv file
*/
$stream = new Yamdi_InputStream(dirname(__FILE__) . '/../trailer_2.flv');
/*
* Constant header
*/
$header = new Yamdi_FlvFileHeader();
$header->read($stream);
$this->assertEqual(true, $header->isValid());
/*
* Constant size of zero tag
*/
$zeroTagSize = new Yamdi_FlvTagSize();
$zeroTagSize->read($stream);
$this->assertEqual(0, $zeroTagSize->size);
// allways 0
/*
* First tag (should be meta)
*/
$tag = new Yamdi_FlvTag();
$tag->read($stream);
$this->assertTrue($tag->isMeta());
$metadata = new Yamdi_FlvMetadataBody();
$metadata->read($tag->readTagBody($stream));
/*
* Previous tag size
*/
$tagSize = new Yamdi_FlvTagSize();
$tagSize->read($stream);
while (!$stream->isEnd()) {
$tag_position = $stream->getPosition();
/*
* Tag
*/
if (!$tag->read($stream)) {
break;
}
$this->assertTrue($tag->isValid());
if ($tag->isVideo()) {
if ($tag->checkIfKeyFrame($stream)) {
$new_filepositions[] = $tag_position;
$new_times[] = $tag->getTimestamp() / 1000.0;
}
}
$tag->skipTagBody($stream);
// wind forward to next tag
/*
* Previous tag size
*/
$tagSize = new Yamdi_FlvTagSize();
if (!$tagSize->read($stream)) {
break;
}
}
$this->assertTrue(is_array($new_filepositions));
$this->assertTrue(count($new_filepositions) > 0);
$this->assertTrue(is_array($new_times));
$this->assertTrue(count($new_times) > 0);
$this->assertEqual(count($new_times), count($new_filepositions));
/*
* Cleanup
*/
$stream->close();
}