AVCSequenceParameterSetReader Class Reference

Collaboration diagram for AVCSequenceParameterSetReader:

Public Member Functions
	__construct ($sps)
	readData ()
	skipBits ($bits)
	getBit ()
	getBits ($bits)
	expGolombUe ()
	expGolombSe ()
	getWidth ()
	getHeight ()

Data Fields
	$sps
	$start = 0
	$currentBytes = 0
	$currentBits = 0
	$width
	$height

Detailed Description

Definition at line 630 of file module.audio-video.flv.php.

Constructor & Destructor Documentation

__construct()

AVCSequenceParameterSetReader::__construct

(

$sps

)

Definition at line 638 of file module.audio-video.flv.php.

                                          {
                $this->sps = $sps;
        }

Member Function Documentation

expGolombSe()

AVCSequenceParameterSetReader::expGolombSe

(

)

Definition at line 729 of file module.audio-video.flv.php.

References $result.

                                      {
                $result = $this->expGolombUe();
                if (($result & 0x01) == 0) {
                        return -($result >> 1);
                } else {
                        return ($result + 1) >> 1;
                }
        }

expGolombUe()

AVCSequenceParameterSetReader::expGolombUe

(

)

Definition at line 714 of file module.audio-video.flv.php.

                                      {
                $significantBits = 0;
                $bit = $this->getBit();
                while ($bit == 0) {
                        $significantBits++;
                        $bit = $this->getBit();

                        if ($significantBits > 31) {
                                // something is broken, this is an emergency escape to prevent infinite loops
                                return 0;
                        }
                }
                return (1 << $significantBits) + $this->getBits($significantBits) - 1;
        }

getBit()

AVCSequenceParameterSetReader::getBit

(

)

Definition at line 700 of file module.audio-video.flv.php.

References $result, and getid3_lib\BigEndian2Int().

                                 {
                $result = (getid3_lib::BigEndian2Int(substr($this->sps, $this->currentBytes, 1)) >> (7 - $this->currentBits)) & 0x01;
                $this->skipBits(1);
                return $result;
        }

Here is the call graph for this function:

getBits()

AVCSequenceParameterSetReader::getBits

(

$bits

)

Definition at line 706 of file module.audio-video.flv.php.

References $result.

                                       {
                $result = 0;
                for ($i = 0; $i < $bits; $i++) {
                        $result = ($result << 1) + $this->getBit();
                }
                return $result;
        }

getHeight()

AVCSequenceParameterSetReader::getHeight

(

)

Definition at line 742 of file module.audio-video.flv.php.

                                    {
                return $this->height;
        }

getWidth()

AVCSequenceParameterSetReader::getWidth

(

)

Definition at line 738 of file module.audio-video.flv.php.

                                   {
                return $this->width;
        }

readData()

AVCSequenceParameterSetReader::readData

(

)

Definition at line 642 of file module.audio-video.flv.php.

                                   {
                $this->skipBits(8);
                $this->skipBits(8);
                $profile = $this->getBits(8);                               // read profile
                if ($profile > 0) {
                        $this->skipBits(8);
                        $level_idc = $this->getBits(8);                         // level_idc
                        $this->expGolombUe();                                   // seq_parameter_set_id // sps
                        $this->expGolombUe();                                   // log2_max_frame_num_minus4
                        $picOrderType = $this->expGolombUe();                   // pic_order_cnt_type
                        if ($picOrderType == 0) {
                                $this->expGolombUe();                               // log2_max_pic_order_cnt_lsb_minus4
                        } elseif ($picOrderType == 1) {
                                $this->skipBits(1);                                 // delta_pic_order_always_zero_flag
                                $this->expGolombSe();                               // offset_for_non_ref_pic
                                $this->expGolombSe();                               // offset_for_top_to_bottom_field
                                $num_ref_frames_in_pic_order_cnt_cycle = $this->expGolombUe(); // num_ref_frames_in_pic_order_cnt_cycle
                                for ($i = 0; $i < $num_ref_frames_in_pic_order_cnt_cycle; $i++) {
                                        $this->expGolombSe();                           // offset_for_ref_frame[ i ]
                                }
                        }
                        $this->expGolombUe();                                   // num_ref_frames
                        $this->skipBits(1);                                     // gaps_in_frame_num_value_allowed_flag
                        $pic_width_in_mbs_minus1 = $this->expGolombUe();        // pic_width_in_mbs_minus1
                        $pic_height_in_map_units_minus1 = $this->expGolombUe(); // pic_height_in_map_units_minus1

                        $frame_mbs_only_flag = $this->getBits(1);               // frame_mbs_only_flag
                        if ($frame_mbs_only_flag == 0) {
                                $this->skipBits(1);                                 // mb_adaptive_frame_field_flag
                        }
                        $this->skipBits(1);                                     // direct_8x8_inference_flag
                        $frame_cropping_flag = $this->getBits(1);               // frame_cropping_flag

                        $frame_crop_left_offset   = 0;
                        $frame_crop_right_offset  = 0;
                        $frame_crop_top_offset    = 0;
                        $frame_crop_bottom_offset = 0;

                        if ($frame_cropping_flag) {
                                $frame_crop_left_offset   = $this->expGolombUe();   // frame_crop_left_offset
                                $frame_crop_right_offset  = $this->expGolombUe();   // frame_crop_right_offset
                                $frame_crop_top_offset    = $this->expGolombUe();   // frame_crop_top_offset
                                $frame_crop_bottom_offset = $this->expGolombUe();   // frame_crop_bottom_offset
                        }
                        $this->skipBits(1);                                     // vui_parameters_present_flag
                        // etc

                        $this->width  = (($pic_width_in_mbs_minus1 + 1) * 16) - ($frame_crop_left_offset * 2) - ($frame_crop_right_offset * 2);
                        $this->height = ((2 - $frame_mbs_only_flag) * ($pic_height_in_map_units_minus1 + 1) * 16) - ($frame_crop_top_offset * 2) - ($frame_crop_bottom_offset * 2);
                }
        }

skipBits()

AVCSequenceParameterSetReader::skipBits

(

$bits

)

Definition at line 694 of file module.audio-video.flv.php.

                                        {
                $newBits = $this->currentBits + $bits;
                $this->currentBytes += (int)floor($newBits / 8);
                $this->currentBits = $newBits % 8;
        }

Field Documentation

$currentBits

AVCSequenceParameterSetReader::$currentBits = 0

Definition at line 634 of file module.audio-video.flv.php.

$currentBytes

AVCSequenceParameterSetReader::$currentBytes = 0

Definition at line 633 of file module.audio-video.flv.php.

$height

AVCSequenceParameterSetReader::$height

Definition at line 636 of file module.audio-video.flv.php.

$sps

AVCSequenceParameterSetReader::$sps

Definition at line 631 of file module.audio-video.flv.php.

$start

AVCSequenceParameterSetReader::$start = 0

Definition at line 632 of file module.audio-video.flv.php.

$width

AVCSequenceParameterSetReader::$width

Definition at line 635 of file module.audio-video.flv.php.

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The documentation for this class was generated from the following file:

• Services/MediaObjects/lib/getID3-1.9.10/getid3/module.audio-video.flv.php