Avifinfo
Parser{} │ WP 1.0
Хуков нет.
Использование
$Parser = new Parser(); // use class methods
Методы
- public __construct( $handle )
- public parse_file()
- public parse_ftyp()
- private parse_ipco( $num_remaining_bytes )
- private parse_iprp( $num_remaining_bytes )
- private parse_iref( $num_remaining_bytes )
- private parse_meta( $num_remaining_bytes )
Код Parser{} Parser{} WP 6.5.2
class Parser {
private $handle; // Input stream.
private $num_parsed_boxes = 0;
private $data_was_skipped = false;
public $features;
function __construct( $handle ) {
$this->handle = $handle;
$this->features = new Features();
}
/**
* Parses an "ipco" box.
*
* "ispe" is used for width and height, "pixi" and "av1C" are used for bit depth
* and number of channels, and "auxC" is used for alpha.
*
* @param stream $handle The resource the box will be parsed from.
* @param int $num_remaining_bytes The number of bytes that should be available from the resource.
* @return Status FOUND on success or an error on failure.
*/
private function parse_ipco( $num_remaining_bytes ) {
$box_index = 1; // 1-based index. Used for iterating over properties.
do {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
if ( $status != FOUND ) {
return $status;
}
if ( $box->type == 'ispe' ) {
// See ISO/IEC 23008-12:2017(E) 6.5.3.2
if ( $box->content_size < 8 ) {
return INVALID;
}
if ( !( $data = read( $this->handle, 8 ) ) ) {
return TRUNCATED;
}
$width = read_big_endian( substr( $data, 0, 4 ), 4 );
$height = read_big_endian( substr( $data, 4, 4 ), 4 );
if ( $width == 0 || $height == 0 ) {
return INVALID;
}
if ( count( $this->features->dim_props ) <= MAX_FEATURES &&
$box_index <= MAX_VALUE ) {
$dim_prop_count = count( $this->features->dim_props );
$this->features->dim_props[$dim_prop_count] = new Dim_Prop();
$this->features->dim_props[$dim_prop_count]->property_index = $box_index;
$this->features->dim_props[$dim_prop_count]->width = $width;
$this->features->dim_props[$dim_prop_count]->height = $height;
} else {
$this->data_was_skipped = true;
}
if ( !skip( $this->handle, $box->content_size - 8 ) ) {
return TRUNCATED;
}
} else if ( $box->type == 'pixi' ) {
// See ISO/IEC 23008-12:2017(E) 6.5.6.2
if ( $box->content_size < 1 ) {
return INVALID;
}
if ( !( $data = read( $this->handle, 1 ) ) ) {
return TRUNCATED;
}
$num_channels = read_big_endian( $data, 1 );
if ( $num_channels < 1 ) {
return INVALID;
}
if ( $box->content_size < 1 + $num_channels ) {
return INVALID;
}
if ( !( $data = read( $this->handle, 1 ) ) ) {
return TRUNCATED;
}
$bit_depth = read_big_endian( $data, 1 );
if ( $bit_depth < 1 ) {
return INVALID;
}
for ( $i = 1; $i < $num_channels; ++$i ) {
if ( !( $data = read( $this->handle, 1 ) ) ) {
return TRUNCATED;
}
// Bit depth should be the same for all channels.
if ( read_big_endian( $data, 1 ) != $bit_depth ) {
return INVALID;
}
if ( $i > 32 ) {
return ABORTED; // Be reasonable.
}
}
if ( count( $this->features->chan_props ) <= MAX_FEATURES &&
$box_index <= MAX_VALUE && $bit_depth <= MAX_VALUE &&
$num_channels <= MAX_VALUE ) {
$chan_prop_count = count( $this->features->chan_props );
$this->features->chan_props[$chan_prop_count] = new Chan_Prop();
$this->features->chan_props[$chan_prop_count]->property_index = $box_index;
$this->features->chan_props[$chan_prop_count]->bit_depth = $bit_depth;
$this->features->chan_props[$chan_prop_count]->num_channels = $num_channels;
} else {
$this->data_was_skipped = true;
}
if ( !skip( $this->handle, $box->content_size - ( 1 + $num_channels ) ) ) {
return TRUNCATED;
}
} else if ( $box->type == 'av1C' ) {
// See AV1 Codec ISO Media File Format Binding 2.3.1
// at https://aomediacodec.github.io/av1-isobmff/#av1c
// Only parse the necessary third byte. Assume that the others are valid.
if ( $box->content_size < 3 ) {
return INVALID;
}
if ( !( $data = read( $this->handle, 3 ) ) ) {
return TRUNCATED;
}
$byte = read_big_endian( substr( $data, 2, 1 ), 1 );
$high_bitdepth = ( $byte & 0x40 ) != 0;
$twelve_bit = ( $byte & 0x20 ) != 0;
$monochrome = ( $byte & 0x10 ) != 0;
if ( $twelve_bit && !$high_bitdepth ) {
return INVALID;
}
if ( count( $this->features->chan_props ) <= MAX_FEATURES &&
$box_index <= MAX_VALUE ) {
$chan_prop_count = count( $this->features->chan_props );
$this->features->chan_props[$chan_prop_count] = new Chan_Prop();
$this->features->chan_props[$chan_prop_count]->property_index = $box_index;
$this->features->chan_props[$chan_prop_count]->bit_depth =
$high_bitdepth ? $twelve_bit ? 12 : 10 : 8;
$this->features->chan_props[$chan_prop_count]->num_channels = $monochrome ? 1 : 3;
} else {
$this->data_was_skipped = true;
}
if ( !skip( $this->handle, $box->content_size - 3 ) ) {
return TRUNCATED;
}
} else if ( $box->type == 'auxC' ) {
// See AV1 Image File Format (AVIF) 4
// at https://aomediacodec.github.io/av1-avif/#auxiliary-images
$kAlphaStr = "urn:mpeg:mpegB:cicp:systems:auxiliary:alpha\0";
$kAlphaStrLength = 44; // Includes terminating character.
if ( $box->content_size >= $kAlphaStrLength ) {
if ( !( $data = read( $this->handle, $kAlphaStrLength ) ) ) {
return TRUNCATED;
}
if ( substr( $data, 0, $kAlphaStrLength ) == $kAlphaStr ) {
// Note: It is unlikely but it is possible that this alpha plane does
// not belong to the primary item or a tile. Ignore this issue.
$this->features->has_alpha = true;
}
if ( !skip( $this->handle, $box->content_size - $kAlphaStrLength ) ) {
return TRUNCATED;
}
} else {
if ( !skip( $this->handle, $box->content_size ) ) {
return TRUNCATED;
}
}
} else {
if ( !skip( $this->handle, $box->content_size ) ) {
return TRUNCATED;
}
}
++$box_index;
$num_remaining_bytes -= $box->size;
} while ( $num_remaining_bytes > 0 );
return NOT_FOUND;
}
/**
* Parses an "iprp" box.
*
* The "ipco" box contain the properties which are linked to items by the "ipma" box.
*
* @param stream $handle The resource the box will be parsed from.
* @param int $num_remaining_bytes The number of bytes that should be available from the resource.
* @return Status FOUND on success or an error on failure.
*/
private function parse_iprp( $num_remaining_bytes ) {
do {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
if ( $status != FOUND ) {
return $status;
}
if ( $box->type == 'ipco' ) {
$status = $this->parse_ipco( $box->content_size );
if ( $status != NOT_FOUND ) {
return $status;
}
} else if ( $box->type == 'ipma' ) {
// See ISO/IEC 23008-12:2017(E) 9.3.2
$num_read_bytes = 4;
if ( $box->content_size < $num_read_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $num_read_bytes ) ) ) {
return TRUNCATED;
}
$entry_count = read_big_endian( $data, 4 );
$id_num_bytes = ( $box->version < 1 ) ? 2 : 4;
$index_num_bytes = ( $box->flags & 1 ) ? 2 : 1;
$essential_bit_mask = ( $box->flags & 1 ) ? 0x8000 : 0x80;
for ( $entry = 0; $entry < $entry_count; ++$entry ) {
if ( $entry >= MAX_PROPS ||
count( $this->features->props ) >= MAX_PROPS ) {
$this->data_was_skipped = true;
break;
}
$num_read_bytes += $id_num_bytes + 1;
if ( $box->content_size < $num_read_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $id_num_bytes + 1 ) ) ) {
return TRUNCATED;
}
$item_id = read_big_endian(
substr( $data, 0, $id_num_bytes ), $id_num_bytes );
$association_count = read_big_endian(
substr( $data, $id_num_bytes, 1 ), 1 );
for ( $property = 0; $property < $association_count; ++$property ) {
if ( $property >= MAX_PROPS ||
count( $this->features->props ) >= MAX_PROPS ) {
$this->data_was_skipped = true;
break;
}
$num_read_bytes += $index_num_bytes;
if ( $box->content_size < $num_read_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $index_num_bytes ) ) ) {
return TRUNCATED;
}
$value = read_big_endian( $data, $index_num_bytes );
// $essential = ($value & $essential_bit_mask); // Unused.
$property_index = ( $value & ~$essential_bit_mask );
if ( $property_index <= MAX_VALUE && $item_id <= MAX_VALUE ) {
$prop_count = count( $this->features->props );
$this->features->props[$prop_count] = new Prop();
$this->features->props[$prop_count]->property_index = $property_index;
$this->features->props[$prop_count]->item_id = $item_id;
} else {
$this->data_was_skipped = true;
}
}
if ( $property < $association_count ) {
break; // Do not read garbage.
}
}
// If all features are available now, do not look further.
$status = $this->features->get_primary_item_features();
if ( $status != NOT_FOUND ) {
return $status;
}
// Mostly if 'data_was_skipped'.
if ( !skip( $this->handle, $box->content_size - $num_read_bytes ) ) {
return TRUNCATED;
}
} else {
if ( !skip( $this->handle, $box->content_size ) ) {
return TRUNCATED;
}
}
$num_remaining_bytes -= $box->size;
} while ( $num_remaining_bytes > 0 );
return NOT_FOUND;
}
/**
* Parses an "iref" box.
*
* The "dimg" boxes contain links between tiles and their parent items, which
* can be used to infer bit depth and number of channels for the primary item
* when the latter does not have these properties.
*
* @param stream $handle The resource the box will be parsed from.
* @param int $num_remaining_bytes The number of bytes that should be available from the resource.
* @return Status FOUND on success or an error on failure.
*/
private function parse_iref( $num_remaining_bytes ) {
do {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
if ( $status != FOUND ) {
return $status;
}
if ( $box->type == 'dimg' ) {
// See ISO/IEC 14496-12:2015(E) 8.11.12.2
$num_bytes_per_id = ( $box->version == 0 ) ? 2 : 4;
$num_read_bytes = $num_bytes_per_id + 2;
if ( $box->content_size < $num_read_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $num_read_bytes ) ) ) {
return TRUNCATED;
}
$from_item_id = read_big_endian( $data, $num_bytes_per_id );
$reference_count = read_big_endian( substr( $data, $num_bytes_per_id, 2 ), 2 );
for ( $i = 0; $i < $reference_count; ++$i ) {
if ( $i >= MAX_TILES ) {
$this->data_was_skipped = true;
break;
}
$num_read_bytes += $num_bytes_per_id;
if ( $box->content_size < $num_read_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $num_bytes_per_id ) ) ) {
return TRUNCATED;
}
$to_item_id = read_big_endian( $data, $num_bytes_per_id );
$tile_count = count( $this->features->tiles );
if ( $from_item_id <= MAX_VALUE && $to_item_id <= MAX_VALUE &&
$tile_count < MAX_TILES ) {
$this->features->tiles[$tile_count] = new Tile();
$this->features->tiles[$tile_count]->tile_item_id = $to_item_id;
$this->features->tiles[$tile_count]->parent_item_id = $from_item_id;
} else {
$this->data_was_skipped = true;
}
}
// If all features are available now, do not look further.
$status = $this->features->get_primary_item_features();
if ( $status != NOT_FOUND ) {
return $status;
}
// Mostly if 'data_was_skipped'.
if ( !skip( $this->handle, $box->content_size - $num_read_bytes ) ) {
return TRUNCATED;
}
} else {
if ( !skip( $this->handle, $box->content_size ) ) {
return TRUNCATED;
}
}
$num_remaining_bytes -= $box->size;
} while ( $num_remaining_bytes > 0 );
return NOT_FOUND;
}
/**
* Parses a "meta" box.
*
* It looks for the primary item ID in the "pitm" box and recurses into other boxes
* to find its features.
*
* @param stream $handle The resource the box will be parsed from.
* @param int $num_remaining_bytes The number of bytes that should be available from the resource.
* @return Status FOUND on success or an error on failure.
*/
private function parse_meta( $num_remaining_bytes ) {
do {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
if ( $status != FOUND ) {
return $status;
}
if ( $box->type == 'pitm' ) {
// See ISO/IEC 14496-12:2015(E) 8.11.4.2
$num_bytes_per_id = ( $box->version == 0 ) ? 2 : 4;
if ( $num_bytes_per_id > $num_remaining_bytes ) {
return INVALID;
}
if ( !( $data = read( $this->handle, $num_bytes_per_id ) ) ) {
return TRUNCATED;
}
$primary_item_id = read_big_endian( $data, $num_bytes_per_id );
if ( $primary_item_id > MAX_VALUE ) {
return ABORTED;
}
$this->features->has_primary_item = true;
$this->features->primary_item_id = $primary_item_id;
if ( !skip( $this->handle, $box->content_size - $num_bytes_per_id ) ) {
return TRUNCATED;
}
} else if ( $box->type == 'iprp' ) {
$status = $this->parse_iprp( $box->content_size );
if ( $status != NOT_FOUND ) {
return $status;
}
} else if ( $box->type == 'iref' ) {
$status = $this->parse_iref( $box->content_size );
if ( $status != NOT_FOUND ) {
return $status;
}
} else {
if ( !skip( $this->handle, $box->content_size ) ) {
return TRUNCATED;
}
}
$num_remaining_bytes -= $box->size;
} while ( $num_remaining_bytes != 0 );
// According to ISO/IEC 14496-12:2012(E) 8.11.1.1 there is at most one "meta".
return INVALID;
}
/**
* Parses a file stream.
*
* The file type is checked through the "ftyp" box.
*
* @return bool True if the input stream is an AVIF bitstream or false.
*/
public function parse_ftyp() {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes );
if ( $status != FOUND ) {
return false;
}
if ( $box->type != 'ftyp' ) {
return false;
}
// Iterate over brands. See ISO/IEC 14496-12:2012(E) 4.3.1
if ( $box->content_size < 8 ) {
return false;
}
for ( $i = 0; $i + 4 <= $box->content_size; $i += 4 ) {
if ( !( $data = read( $this->handle, 4 ) ) ) {
return false;
}
if ( $i == 4 ) {
continue; // Skip minor_version.
}
if ( substr( $data, 0, 4 ) == 'avif' || substr( $data, 0, 4 ) == 'avis' ) {
return skip( $this->handle, $box->content_size - ( $i + 4 ) );
}
if ( $i > 32 * 4 ) {
return false; // Be reasonable.
}
}
return false; // No AVIF brand no good.
}
/**
* Parses a file stream.
*
* Features are extracted from the "meta" box.
*
* @return bool True if the main features of the primary item were parsed or false.
*/
public function parse_file() {
$box = new Box();
while ( $box->parse( $this->handle, $this->num_parsed_boxes ) == FOUND ) {
if ( $box->type === 'meta' ) {
if ( $this->parse_meta( $box->content_size ) != FOUND ) {
return false;
}
return true;
}
if ( !skip( $this->handle, $box->content_size ) ) {
return false;
}
}
return false; // No "meta" no good.
}
}