-- Dissector for rtp payload PS
-- According to RFC2250 to dissector payload of RTP to NALU
-- Author: yangxing ([email protected])
------------------------------------------------------------------------------------------------
do
    local version_str = string.match(_VERSION, "%d+[.]%d*")
	local version_num = version_str and tonumber(version_str) or 5.1
    local bit = (version_num >= 5.2) and require("bit32") or require("bit")

    local ps_stream_type_vals = {
        [0x0f] = "AAC",
        [0x10] = "MPEG-4 Video",
        [0x1b] = "H.264",
        [0x24] = "H.265",
        [0x80] = "SVAC Video",
        [0x90] = "G.711A",
        [0x91] = "G.711U",
        [0x92] = "G.722.1",
        [0x93] = "G.723.1",
        [0x99] = "G.729",
        [0x9b] = "SVAC Audio",
    }
    local h264_nal_unit_type_vals = {
        [0] = "Unspecified",
        [1] = "Coded slice of a non-IDR picture",
        [2] = "Coded slice data partition A",
        [3] = "Coded slice data partition B",
        [4] = "Coded slice data partition C",
        [5] = "Coded slice of an IDR picture",
        [6] = "Supplemental enhancement information (SEI)",
        [7] = "Sequence parameter set",
        [8] = "Picture parameter set",
        [9] = "Access unit delimiter",
        [10] = "End of sequence",
        [11] = "End of stream",
        [12] = "Filler data",
        [13] = "Sequence parameter set extension",
        [14] = "Prefix",
        [15] = "Subset sequence parameter set",
        [16] = "Reserved",
        [17] = "Reserved",
        [18] = "Reserved",
        [19] = "Coded slice of an auxiliary coded picture without partitioning",
        [20] = "Coded slice extension",
        [21] = "Coded slice extension for depth view components",
        [22] = "Reserved",
        [23] = "Reserved"
    }
    local h264_type_summary_values = {
        [0] = "Undefined",
        [1] = "non-IDR-Slice",
        [2] = "Slice-A",
        [3] = "Slice-B",
        [4] = "Slice-C",
        [5] = "IDR-Slice",
        [6] = "SEI",
        [7] = "SPS",
        [8] = "PPS",
        [9] = "AUD",
        [10] = "End-of-Seq",
        [11] = "End-of-Stream",
        [12] = "Filler",
        [13] = "SPS-Ext",
        [14] = "Prefix",
        [15] = "Subset-SPS",
        [16] = "Reserved",
        [17] = "Reserved",
        [18] = "Reserved",
        [19] = "Slice-Aux",
        [20] = "Slice-Ext",
        [21] = "Slice-Ext-Depth",
        [22] = "Reserved",
        [23] = "Reserved"
    }
    local h265_nal_unit_type_vals = {
        [0] = "Coded slice segment of a non-TSA, non-STSA trailing picture",
        [1] = "Coded slice segment of a non-TSA, non-STSA trailing picture",
        [2] = "Coded slice segment of a TSA picture",
        [3] = "Coded slice segment of a TSA picture",
        [4] = "Coded slice segment of an STSA picture",
        [5] = "Coded slice segment of an STSA picture",
        [6] = "Coded slice segment of a RADL picture",
        [7] = "Coded slice segment of a RADL picture",
        [8] = "Coded slice segment of a RASL picture",
        [9] = "Coded slice segment of a RASL picture",
        [10] = "Reserved non-IRAP SLNR VCL NAL unit types",
        [11] = "Reserved non-IRAP sub-layer reference VCL NAL unit types",
        [12] = "Reserved non-IRAP SLNR VCL NAL unit types",
        [13] = "Reserved non-IRAP sub-layer reference VCL NAL unit types",
        [14] = "Reserved non-IRAP SLNR VCL NAL unit types",
        [15] = "Reserved non-IRAP sub-layer reference VCL NAL unit types",
        [16] = "Coded slice segment of a BLA picture",
        [17] = "Coded slice segment of a BLA picture",
        [18] = "Coded slice segment of a BLA picture",
        [19] = "Coded slice segment of an IDR picture",
        [20] = "Coded slice segment of an IDR picture",
        [21] = "Coded slice segment of a CRA picture",
        [22] = "Reserved IRAP VCL NAL unit types",
        [23] = "Reserved IRAP VCL NAL unit types",
        [24 .. 31] = "Reserved non-IRAP VCL NAL unit types",
        [32] = "Video parameter set",
        [33] = "Sequence parameter set",
        [34] = "Picture parameter set",
        [35] = "Access unit delimiter",
        [36] = "End of sequence",
        [37] = "End of bitstream",
        [38] = "Filler data",
        [39] = "Prefix Supplemental enhancement information",
        [40] = "Suffix Supplemental enhancement information",
        [40 .. 47] = "Reserved",
        [48 .. 63] = "Unspecified"
    }
    local h265_type_summary_values = {
        [0] = "non-TSA, non-STSA",
        [1] = "non-TSA, non-STSA",
        [2] = "TSA",
        [3] = "TSA",
        [4] = "STSA",
        [5] = "STSA",
        [6] = "RADL",
        [7] = "RADL",
        [8] = "RASL",
        [9] = "RASL",
        [10] = "non-IRAP-SLNR-VCL",
        [11] = "non-IRAP-sub-layer",
        [12] = "non-IRAP-SLNR",
        [13] = "non-IRAP-sub-layer",
        [14] = "non-IRAP-SLNR",
        [15] = "non-IRAP-sub-layer",
        [16] = "BLA",
        [17] = "BLA",
        [18] = "BLA",
        [19] = "IDR",
        [20] = "IDR",
        [21] = "CRAe",
        [22] = "IRAP-VCL",
        [23] = "IRAP-VCL",
        [24 .. 31] = "non-IRAP-VCL",
        [32] = "VPS",
        [33] = "SPS",
        [34] = "PPS",
        [35] = "AUD",
        [36] = "End-of-Seq",
        [37] = "End-of-Stream",
        [38] = "Filler",
        [39] = "Prefix-SEI",
        [40] = "Suffix-SEI",
        [40 .. 47] = "Reserved",
        [48 .. 63] = "Unspecified"
    }
    local function get_enum_name(list, index)
        local value = list[index]
        return value and value or string.format("Unknown (%d)",index)
    end
    
    local proto_ps = Proto("ps", "PS")
    
    local ps_hdr = ProtoField.none("ps.pack_header", "PS Header")
    local ps_start_code = ProtoField.bytes("ps.pack_start_code", "Start code", base.SPACE)
    local ps_scr_base = ProtoField.none("ps.scr_base", "SCR base")
    local ps_scr_ext = ProtoField.none("ps.scr_ext", "SCR extension")
    local ps_multiplex_rate = ProtoField.new("Multiplex rate", "ps.multiplex_rate", ftypes.UINT24, nil, base.DEC, 0xfffffc)
    local ps_stuffing_length = ProtoField.new("Stuffing length", "ps.stuffing_length", ftypes.UINT8, nil, base.DEC, 0x07)
    local ps_stuffing_bytes = ProtoField.bytes("ps.stuffing_bytes", "Stuffing bytes")
    
    local ps_system_header = ProtoField.none("ps.system_header", "System Header")
    local ps_system_header_start_code = ProtoField.bytes("ps.system_header.start_code", "Start code", base.SPACE)
    local ps_system_header_length = ProtoField.new("Header length", "ps.system_header.header_length", ftypes.UINT16, nil, base.DEC)
    local ps_system_header_rate_bound = ProtoField.new("Rate bound", "ps.system_header.rate_bound", ftypes.UINT24, nil, base.DEC, 0x7ffffe)
    local ps_system_header_audio_bound = ProtoField.new("Audio bound", "ps.system_header.audio_bound", ftypes.UINT8, nil, base.DEC, 0xfc)
    local ps_system_header_fixed_flag = ProtoField.new("Fixed flag", "ps.system_header.fixed_flag", ftypes.UINT8, nil, base.DEC, 0x02)
    local ps_system_header_CSPS_flag = ProtoField.new("CSPS flag", "ps.system_header.csps_flag", ftypes.UINT8, nil, base.DEC, 0x01)
    local ps_system_header_system_audio_lock_flag = ProtoField.new("System audio lock flag", "ps.system_header.system_audio_lock_flag", ftypes.UINT8, nil, base.DEC, 0x80)
    local ps_system_header_system_video_lock_flag = ProtoField.new("System video lock flag", "ps.system_header.system_video_lock_flag", ftypes.UINT8, nil, base.DEC, 0x40)
    local ps_system_header_vedio_bound = ProtoField.new("Vedio bound", "ps.system_header.vedio_bound", ftypes.UINT8, nil, base.DEC, 0x1f)
    local ps_system_header_packet_rate_restriction_flag = ProtoField.new("Packet rate restriction flag", "ps.system_header.packet_rate_restriction_flag", ftypes.UINT8, nil, base.DEC, 0x80)
    local ps_system_header_stream_id = ProtoField.new("Stream ID", "ps.system_header.stream_id", ftypes.UINT8, nil, base.HEX)
    local ps_system_header_P_STD_scale = ProtoField.new("P-STD buffer bound scale", "ps.system_header.buffer_bound_scale", ftypes.UINT16, nil, base.DEC, 0x2000)
    local ps_system_header_P_STD_bound = ProtoField.new("P-STD buffer size bound", "ps.system_header.buffer_size_bound", ftypes.UINT16, nil, base.DEC, 0x1fff)

    local ps_program_stream = ProtoField.none("ps.program_map", "Program Stream Map")
    local ps_program_stream_start_code = ProtoField.bytes("ps.program_map.start_code", "Start code", base.SPACE)
    local ps_program_stream_id = ProtoField.new("Stream ID", "ps.program_map.stream_id", ftypes.UINT8, nil, base.HEX)
    local ps_program_stream_length = ProtoField.new("Header length", "ps.program_map.header_length", ftypes.UINT16, nil, base.DEC)
    local ps_program_stream_current_next_indicator = ProtoField.new("Current next indicator", "ps.program_map.current_next_indicator", ftypes.UINT8, nil, base.DEC, 0x80)
    local ps_program_stream_map_version = ProtoField.new("Version", "ps.program_map.version", ftypes.UINT8, nil, base.DEC, 0x1f)
    local ps_program_stream_info_length = ProtoField.new("Info length", "ps.program_map.info_length", ftypes.UINT16, nil, base.DEC)
    local ps_program_stream_map_length = ProtoField.new("Map length", "ps.program_map.map_length", ftypes.UINT16, nil, base.DEC)
    local ps_program_stream_map_stream_type = ProtoField.new("Stream type", "ps.program_map.map.stream_type", ftypes.UINT8, ps_stream_type_vals, base.DEC)
    local ps_program_stream_map_stream_id = ProtoField.new("Stream ID", "ps.program_map.map.stream_id", ftypes.UINT8, nil, base.HEX)
    local ps_program_stream_map_info_length = ProtoField.new("Stream info length", "ps.program_map.map.stream_info_length", ftypes.UINT16, nil, base.DEC)
    local ps_program_stream_CRC = ProtoField.bytes("ps.program_map.crc", "CRC", base.SPACE)
    
    local ps_pes = ProtoField.none("ps.pes", "PES Packet")
    local ps_pes_start_code = ProtoField.bytes("ps.pes.start_code", "Start code", base.SPACE)
    local ps_pes_stream_id = ProtoField.new("Stream ID", "ps.pes.stream_id", ftypes.UINT8, nil, base.HEX)
    local ps_pes_length = ProtoField.new("Length", "ps.pes.packet_length", ftypes.UINT16, nil, base.DEC)
    local ps_pes_scrambing_control = ProtoField.new("Scrambing control", "ps.pes.scrambing_control", ftypes.UINT8, nil, base.DEC, 0x30)
    local ps_pes_priority = ProtoField.new("Priority", "ps.pes.priority", ftypes.UINT8, nil, base.DEC, 0x08)
    local ps_pes_alignment = ProtoField.new("Alignment", "ps.pes.alignment", ftypes.UINT8, nil, base.DEC, 0x04)
    local ps_pes_copyright = ProtoField.new("Copyright", "ps.pes.copyright", ftypes.UINT8, nil, base.DEC, 0x02)
    local ps_pes_original = ProtoField.new("Original", "ps.pes.original", ftypes.UINT8, nil, base.DEC, 0x01)
    local ps_pes_pts_dts_flag = ProtoField.new("PTS DTS flag", "ps.pes.pts_dts_flag", ftypes.UINT8, nil, base.DEC, 0xc0)
    local ps_pes_escr_flag = ProtoField.new("ESCR flag", "ps.pes.escr_flag", ftypes.UINT8, nil, base.DEC, 0x20)
    local ps_pes_es_rate_flag = ProtoField.new("ES rate flag", "ps.pes.es_rate_flag", ftypes.UINT8, nil, base.DEC, 0x10)
    local ps_pes_dsm_trick_mode_flag = ProtoField.new("DSM trick mode flag", "ps.pes.dsm_trick_mode_flag", ftypes.UINT8, nil, base.DEC, 0x08)
    local ps_pes_additional_info_flag = ProtoField.new("Additional info flag", "ps.pes.additional_info_flag", ftypes.UINT8, nil, base.DEC, 0x04)
    local ps_pes_crc_flag = ProtoField.new("CRC flag", "ps.pes.crc_flag", ftypes.UINT8, nil, base.DEC, 0x02)
    local ps_pes_extension_flag = ProtoField.new("Extension flag", "ps.pes.extension_flag", ftypes.UINT8, nil, base.DEC, 0x01)
    local ps_pes_header_data_length = ProtoField.new("Header Data Length", "ps.pes.header_data_length", ftypes.UINT8, nil, base.DEC)
    local ps_pes_header_data_bytes = ProtoField.bytes("ps.pes.header_data_bytes", "Header Data bytes", base.SPACE)
    local ps_pes_pts = ProtoField.none("ps.pes.pts", "PTS")
    local ps_pes_dts = ProtoField.none("ps.pes.dts", "DTS")
    local ps_pes_escr = ProtoField.none("ps.pes.escr", "ESCR")
    local ps_pes_es_rate = ProtoField.none("ps.pes.es_rate", "ES rate")
    local ps_pes_dsm_trick_mode = ProtoField.new("DSM trick mode", "ps.pes.dsm_trick_mode", ftypes.UINT8, nil, base.HEX)
    local ps_pes_additional_info = ProtoField.new("Copyright Info", "ps.pes.additional_info", ftypes.UINT8, nil, base.HEX)
    local ps_pes_crc = ProtoField.new("CRC", "ps.pes.crc", ftypes.UINT16, nil, base.HEX)
    local ps_pes_extension = ProtoField.new("Extension", "ps.pes.extension", ftypes.UINT8, nil, base.HEX)
    local ps_pes_data_bytes = ProtoField.bytes("ps.pes.data_bytes", "Data bytes")
    local ps_data = ProtoField.bytes("ps.data", "Data")

    local h26x_f_bit_vals = {
        [1] = "Bit errors or other syntax violations",
        [0] = "No bit errors or other syntax violations"
    }
    local h264_f_bit = ProtoField.new("F bit", "ps.pes.h264.f", ftypes.UINT8, h26x_f_bit_vals, base.DEC, 0x80)
    local h264_nal_ref_idc = ProtoField.new("Nal_ref_idc (NRI)", "ps.pes.h264.layerid", ftypes.UINT8, nil, base.DEC, 0x60)
    local h264_nal_unit_type = ProtoField.new("Type", "ps.pes.h264.nal_unit_type", ftypes.UINT8, h264_nal_unit_type_vals, base.DEC, 0x1f)

    local h265_f_bit = ProtoField.new("F bit", "ps.pes.h265.f", ftypes.UINT16, h26x_f_bit_vals, base.DEC, 0x8000)
    local h265_nal_unit_type = ProtoField.new("Type", "ps.pes.h265.nal_unit_type", ftypes.UINT16, h265_nal_unit_type_vals, base.DEC, 0x7E00)
    local h265_nal_layer_id = ProtoField.new("Layer ID", "ps.pes.h265.layerid", ftypes.UINT16, nil, base.DEC, 0x01F8)
    local h265_nal_temporal_id = ProtoField.new("TID", "ps.pes.h265.tid", ftypes.UINT16, nil, base.DEC, 0x0007)
    
    proto_ps.fields = {
        ps_hdr,ps_start_code,ps_scr_base,ps_scr_ext,ps_multiplex_rate,ps_stuffing_length,ps_stuffing_bytes,
        ps_system_header,ps_system_header_start_code,ps_system_header_length,ps_system_header_rate_bound,ps_system_header_audio_bound,ps_system_header_fixed_flag,ps_system_header_CSPS_flag,ps_system_header_system_audio_lock_flag,ps_system_header_system_video_lock_flag,ps_system_header_vedio_bound,ps_system_header_packet_rate_restriction_flag,ps_system_header_stream_id,ps_system_header_P_STD_scale,ps_system_header_P_STD_bound,
        ps_program_stream,ps_program_stream_start_code,ps_program_stream_id,ps_program_stream_length,ps_program_stream_current_next_indicator,ps_program_stream_map_version,ps_program_stream_info_length,ps_program_stream_map_length,ps_program_stream_map_stream_type,ps_program_stream_map_stream_id,ps_program_stream_map_info_length,ps_program_stream_CRC,
        ps_pes,ps_pes_start_code,ps_pes_stream_id,ps_pes_length,ps_pes_scrambing_control,ps_pes_priority,ps_pes_alignment,ps_pes_copyright,ps_pes_original,ps_pes_pts_dts_flag,ps_pes_escr_flag,ps_pes_es_rate_flag,ps_pes_dsm_trick_mode_flag,ps_pes_additional_info_flag,ps_pes_crc_flag,ps_pes_extension_flag,
        ps_pes_header_data_length,ps_pes_header_data_bytes,ps_pes_pts,ps_pes_dts,ps_pes_escr,ps_pes_es_rate,ps_pes_dsm_trick_mode,ps_pes_additional_info,ps_pes_crc,ps_pes_extension,ps_pes_data_bytes,
        ps_data,h264_f_bit,h264_nal_ref_idc,h264_nal_unit_type,h265_f_bit,h265_nal_unit_type,h265_nal_layer_id,h265_nal_temporal_id
    }

    -- local frame_num = Field.new("frame.number")
    -- variable for storing stream info
    local stream_info_map = {}
    local stream_info_follow = nil

    function is_ps_header(tvb, offset)
        if (tvb:len() < (offset+4)) then
            return false
        end
        
        if ((tvb:range(offset, 1):uint() == 0x00) and (tvb:range(offset+1, 1):uint() == 0x00)
            and (tvb:range(offset+2, 1):uint() == 0x01) and (tvb:range(offset+3, 1):uint() == 0xba)) then
            return true
        else
            return false
        end
    end
    function is_system_header(tvb, offset)
        if (tvb:len() < (offset+4)) then
            return false
        end
        
        --print(string.format("start code %x %x %x %x",tvb:range(offset, 1):uint(),tvb:range(offset+1, 1):uint(),tvb:range(offset+2, 1):uint(),tvb:range(offset+3, 1):uint()))
        if ((tvb:range(offset, 1):uint() == 0x00) and (tvb:range(offset+1, 1):uint() == 0x00)
            and (tvb:range(offset+2, 1):uint() == 0x01) and (tvb:range(offset+3, 1):uint() == 0xbb)) then
            return true
        else
            return false
        end
    end
    function is_pes_header(tvb, offset)
        if (tvb:len() < (offset+4)) then
            return false
        end
        if ((tvb:range(offset, 1):uint() == 0x00) and (tvb:range(offset+1, 1):uint() == 0x00)
            and (tvb:range(offset+2, 1):uint() == 0x01)) then
            return true
        else
            return false
        end
    end
    function is_raw_start(tvb, offset)
        if (tvb:len() < (offset+4)) then
            return false
        end
        if ((tvb:range(offset, 1):uint() == 0x00) and (tvb:range(offset+1, 1):uint() == 0x00)
            and (tvb:range(offset+2, 1):uint() == 0x00) and (tvb:range(offset+3, 1):uint() == 0x01)) then
            return true
        else
            return false
        end
    end
    function dis_ps_packet_header(tvb, tree, offset)
        -- PS packet header
        local stuffing_size = tvb:range(offset+13,1):bitfield(5, 3)
        local ps_hdr_tree = tree:add(ps_hdr, tvb:range(offset,14+stuffing_size))
        ps_hdr_tree:add(ps_start_code, tvb:range(offset,4))
        
        local scr_1 = tvb:range(offset+4,1):bitfield(2,3)
        local scr_2 = tvb:range(offset+4,3):bitfield(6,15)
        local scr_3 = tvb:range(offset+6,3):bitfield(6,15)
        local scr_e = tvb:range(offset+8,2):bitfield(6,9)
        local scr = bit.lshift(scr_1,30)+bit.lshift(scr_2,15)+scr_3
        ps_hdr_tree:add(ps_scr_base, tvb:range(offset+4,6)):append_text(string.format(": %u",scr))
        ps_hdr_tree:add(ps_scr_ext, tvb:range(offset+4,6)):append_text(string.format(": %u",scr_e))
        ps_hdr_tree:add(ps_multiplex_rate, tvb:range(offset+10,3))
        ps_hdr_tree:add(ps_stuffing_length, tvb:range(offset+13,1))
        if (stuffing_size > 0) then
            ps_hdr_tree:add(ps_stuffing_bytes, tvb:range(offset+14,stuffing_size))
        end
    end
    function dis_system_header(tvb, tree, offset)
        -- System header
        local system_header_length = tvb:range(offset+4, 2):uint()
        local ps_system_header_tree = tree:add(ps_system_header, tvb:range(offset,system_header_length+4+2))
        ps_system_header_tree:add(ps_system_header_start_code, tvb:range(offset,4))
        ps_system_header_tree:add(ps_system_header_length, tvb:range(offset+4,2))
        ps_system_header_tree:add(ps_system_header_rate_bound, tvb:range(offset+6,3))
        ps_system_header_tree:add(ps_system_header_audio_bound, tvb:range(offset+9,1))
        ps_system_header_tree:add(ps_system_header_fixed_flag, tvb:range(offset+9,1))
        ps_system_header_tree:add(ps_system_header_CSPS_flag, tvb:range(offset+9,1))
        ps_system_header_tree:add(ps_system_header_system_audio_lock_flag, tvb:range(offset+10,1))
        ps_system_header_tree:add(ps_system_header_system_video_lock_flag, tvb:range(offset+10,1))
        ps_system_header_tree:add(ps_system_header_vedio_bound, tvb:range(offset+10,1))
        ps_system_header_tree:add(ps_system_header_packet_rate_restriction_flag, tvb:range(offset+11,1))
        if (system_header_length>6) then
            local remain_length = system_header_length-6
            local shif = offset+12
            repeat
                ps_system_header_tree:add(ps_system_header_stream_id, tvb:range(shif,1))
                ps_system_header_tree:add(ps_system_header_P_STD_scale, tvb:range(shif+1,2))
                ps_system_header_tree:add(ps_system_header_P_STD_bound, tvb:range(shif+1,2))
                shif = shif+3
                remain_length = remain_length-3
            until(remain_length<=0)
        end
    end
    function dis_stream_map(tvb, tree, offset)
        -- Program stream map
        local program_map_length = tvb:range(offset+4, 2):uint()
        local ps_program_map_tree = tree:add(ps_program_stream, tvb:range(offset,program_map_length+4+2))
        ps_program_map_tree:add(ps_program_stream_start_code, tvb:range(offset,3))
        ps_program_map_tree:add(ps_program_stream_id, tvb:range(offset+3,1))
        ps_program_map_tree:add(ps_program_stream_length, tvb:range(offset+4,2))
        ps_program_map_tree:add(ps_program_stream_current_next_indicator, tvb:range(offset+6,1))
        ps_program_map_tree:add(ps_program_stream_map_version, tvb:range(offset+6,1))
        ps_program_map_tree:add(ps_program_stream_info_length, tvb:range(offset+8,2))
        local info_len = tvb:range(offset+8, 2):uint()

        ps_program_map_tree:add(ps_program_stream_map_length, tvb:range(offset+10+info_len,2)) --10 = 8+2(info len)
        local map_len = tvb:range(offset+10+info_len, 2):uint()
        local remain_length = map_len
        local shif = offset+12+info_len
        repeat
            ps_program_map_tree:add(ps_program_stream_map_stream_type, tvb:range(shif,1))
            ps_program_map_tree:add(ps_program_stream_map_stream_id, tvb:range(shif+1,1))
            local stream_type = tvb:range(shif,1):uint()
            local stream_id = tvb:range(shif+1,1):uint()
            stream_info_map[stream_id] = get_enum_name(ps_stream_type_vals, stream_type)
            ps_program_map_tree:add(ps_program_stream_map_info_length, tvb:range(shif+2,2))
            local map_info_len = tvb:range(shif+2, 2):uint()
            shif = shif+4+map_info_len
            remain_length = remain_length-4-map_info_len
        until(remain_length<=0)

        ps_program_map_tree:add(ps_program_stream_CRC, tvb:range(offset+12+info_len+map_len,4)) --12 = 8+2(info len)+2(map len)
    end
    function dis_pes(tvb, tree, offset, pinfo)
        -- PES header
        local pes_length = tvb:range(offset+4, 2):uint()
        local tvb_len = tvb:len()
        local complete_packet = tvb_len>(offset+pes_length+6)
        local ps_pes_tree = tree:add(ps_pes, tvb:range(offset,complete_packet and (pes_length+4+2) or (tvb_len-offset)))
        ps_pes_tree:add(ps_pes_start_code, tvb:range(offset,3))
        ps_pes_tree:add(ps_pes_stream_id, tvb:range(offset+3,1))
        local pes_length_tree = ps_pes_tree:add(ps_pes_length, tvb:range(offset+4,2))

        ps_pes_tree:add(ps_pes_scrambing_control, tvb:range(offset+6,1))
        ps_pes_tree:add(ps_pes_priority, tvb:range(offset+6,1))
        ps_pes_tree:add(ps_pes_alignment, tvb:range(offset+6,1))
        ps_pes_tree:add(ps_pes_copyright, tvb:range(offset+6,1))
        ps_pes_tree:add(ps_pes_original, tvb:range(offset+6,1))

        ps_pes_tree:add(ps_pes_pts_dts_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_escr_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_es_rate_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_dsm_trick_mode_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_additional_info_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_crc_flag, tvb:range(offset+7,1))
        ps_pes_tree:add(ps_pes_extension_flag, tvb:range(offset+7,1))

        local pes_header_data_len = tvb:range(offset+8, 1):uint()
        local header_data_tree = ps_pes_tree:add(ps_pes_header_data_length, tvb:range(offset+8,1))
        pes_length_tree:append_text(string.format(" (data Len: %u)",pes_length-pes_header_data_len-3))
        if pes_header_data_len>0 then
            header_data_tree:add(ps_pes_header_data_bytes, tvb:range(offset+9,pes_header_data_len))

            local index = offset+9
            local pts_dts_flag = tvb:range(offset+7,1):bitfield(0,2)
            if pts_dts_flag == 0x2 then
                local pts_1 = tvb:range(index,1):bitfield(4,3)
                local pts_2 = tvb:range(index+1,2):bitfield(0,15)
                local pts_3 = tvb:range(index+3,2):bitfield(0,15)
                local pts = bit.lshift(pts_1,30)+bit.lshift(pts_2,15)+pts_3
                ps_pes_tree:add(ps_pes_pts, tvb:range(index,5)):append_text(string.format(": %u",pts))
                index = index + 5
            elseif pts_dts_flag == 0x3 then
                local pts_1 = tvb:range(index,1):bitfield(4,3)
                local pts_2 = tvb:range(index+1,2):bitfield(0,15)
                local pts_3 = tvb:range(index+3,2):bitfield(0,15)
                local pts = bit.lshift(pts_1,30)+bit.lshift(pts_2,15)+pts_3
                ps_pes_tree:add(ps_pes_pts, tvb:range(index,5)):append_text(string.format(": %u",pts))

                local dts_1 = tvb:range(index+5,1):bitfield(4,3)
                local dts_2 = tvb:range(index+6,2):bitfield(0,15)
                local dts_3 = tvb:range(indext+8,2):bitfield(0,15)
                local dts = bit.lshift(dts_1,30)+bit.lshift(dts_2,15)+dts_3
                ps_pes_tree:add(ps_pes_dts, tvb:range(index+5,5)):append_text(string.format(": %u",dts))
                index = index + 10
            end
            local escr_flag = tvb:range(offset+7,1):bitfield(2,1)
            if escr_flag == 1 then
                local escr_1 = tvb:range(index,1):bitfield(2,3)
                local escr_2 = tvb:range(index,3):bitfield(6,15)
                local escr_3 = tvb:range(index+2,3):bitfield(6,15)
                local escr_e = tvb:range(index+4,2):bitfield(6,9)
                local escr = bit.lshift(escr_1,30)+bit.lshift(escr_2,15)+escr_3
                ps_pes_tree:add(ps_pes_escr, tvb:range(index,6)):append_text(string.format(": %u, extension: %u",escr,escr_e))
                index = index + 6
            end
            local es_rate_flag = tvb:range(offset+7,1):bitfield(3,1)
            if es_rate_flag == 1 then
                local es_rate = tvb:range(index,3):bitfield(1,22)
                ps_pes_tree:add(ps_pes_es_rate, tvb:range(index,3)):append_text(string.format(": %u",dts))
                index = index + 3
            end
            local dsm_trick_mode_flag = tvb:range(offset+7,1):bitfield(4,1)
            if dsm_trick_mode_flag == 1 then
                ps_pes_tree:add(ps_pes_dsm_trick_mode, tvb:range(index,1))
                index = index + 1
            end
            local additional_info_flag = tvb:range(offset+7,1):bitfield(5,1)
            if additional_info_flag == 1 then
                ps_pes_tree:add(ps_pes_additional_info, tvb:range(index,1))
                index = index + 1
            end
            local crc_flag = tvb:range(offset+7,1):bitfield(6,1)
            if crc_flag == 1 then
                ps_pes_tree:add(ps_pes_crc, tvb:range(index,2))
                index = index + 2
            end
            local extension_flag = tvb:range(offset+7,1):bitfield(7,1)
            if extension_flag == 1 then
                ps_pes_tree:add(ps_pes_extension, tvb:range(index,1))
                index = index + 1
            end
        end

        local stream_id = tvb:range(offset+3,1):uint()
        local stream_id_name = stream_info_map[stream_id]
        if stream_id_name then
            stream_info_follow = stream_id_name
        end

        -- Start code 3, stream id 1, packet length 2, scrambing|PTS 2, Header length 1
        if offset+9+pes_header_data_len>=tvb_len then
            return
        end

        -- Raw data
        local current_len = complete_packet and (pes_length-3-pes_header_data_len) or (tvb_len-offset-9-pes_header_data_len)
        local media_raw_tree = ps_pes_tree:add(ps_pes_data_bytes, tvb:range(offset+9+pes_header_data_len, current_len))
        media_raw_tree:set_text(stream_info_follow)
        media_raw_tree:append_text(string.format(" (%d)",current_len))

        local shif = offset+9+pes_header_data_len+4
        if "H.264" == stream_info_follow then
            media_raw_tree:add(h264_f_bit, tvb:range(shif,1))
            media_raw_tree:add(h264_nal_ref_idc, tvb:range(shif,1))
            media_raw_tree:add(h264_nal_unit_type, tvb:range(shif,1))
            local type = tvb:range(shif,1):bitfield(3, 5)
            pinfo.columns.info:append(" ")
            pinfo.columns.info:append(get_enum_name(h264_type_summary_values, type))
        elseif "H.265" == stream_info_follow then
            media_raw_tree:add(h265_f_bit, tvb:range(shif,2))
            media_raw_tree:add(h265_nal_unit_type, tvb:range(shif,2))
            media_raw_tree:add(h265_nal_layer_id, tvb:range(shif,2))
            media_raw_tree:add(h265_nal_temporal_id, tvb:range(shif,2))
            local type = tvb:range(shif,2):bitfield(1, 6)
            pinfo.columns.info:append(" ")
            pinfo.columns.info:append(get_enum_name(h265_type_summary_values, type))
        end
        
    end
    function dis_raw_data(tvb, tree, offset, pinfo)
        local tvb_len = tvb:len()
        local media_raw_tree = tree:add(ps_pes_data_bytes, tvb:range(offset, tvb_len-offset))
        if stream_info_follow then
            media_raw_tree:set_text(stream_info_follow)
        end
        media_raw_tree:append_text(string.format(" (%d)",tvb_len-offset))
    end
    -- PS dissector for rtp payload
    function proto_ps.dissector(tvb, pinfo, tree)
        -- local frame_seqs = frame_num()
        -- if (frame_seqs.value == 1)

        -- add proto item to tree
        local proto_tree = tree:add(proto_ps, tvb())
        local offset = 0
        
        if (is_ps_header(tvb, offset)) then
            local stuffing_size = tvb:range(offset+13,1):bitfield(5, 3)
            dis_ps_packet_header(tvb, proto_tree, offset)
            offset = offset + 14 + stuffing_size

            if (is_system_header(tvb, offset)) then
                local system_header_length = tvb:range(offset+4, 2):uint()
                dis_system_header(tvb, proto_tree, offset)
                offset = offset + 4 + 2 + system_header_length
                
                -- program stream map
                local program_map_length = tvb:range(offset+4, 2):uint()
                dis_stream_map(tvb, proto_tree, offset)
                offset = offset + 4 + 2 + program_map_length
            end
            
            while (is_pes_header(tvb, offset))
            do
                local pes_length = tvb:range(offset+4, 2):uint()
                dis_pes(tvb, proto_tree, offset, pinfo)
                offset = offset + 4 + 2 + pes_length
            end
        else
            if (is_pes_header(tvb, offset)) then
                dis_pes(tvb, proto_tree, offset, pinfo)
            else
                dis_raw_data(tvb, proto_tree, offset, pinfo)
            end
        end
        
        pinfo.columns.protocol = "PS"
    end

    -- set this protocal preferences
    local prefs = proto_ps.prefs
    prefs.dyn_pt = Pref.range("PS dynamic payload type", "", "Dynamic payload types which will be interpreted as PS; Values must be in the range 96 - 127", 127)

    -- register this dissector to dynamic payload type dissectorTable
    local dyn_payload_type_table = DissectorTable.get("rtp_dyn_payload_type")
    dyn_payload_type_table:add("ps", proto_ps)

    -- register this dissector to specific payload type (specified in preferences windows)
    local payload_type_table = DissectorTable.get("rtp.pt")
    local dyn_pt_number = nil
    local old_dyn_pt = nil
    local old_dissector = nil
    
    function proto_ps.init()
        if (prefs.dyn_pt ~= old_dyn_pt) then
            if (old_dyn_pt ~= nil) then -- reset old dissector
                if (old_dissector == nil) then -- just remove this proto
                    payload_type_table:remove(old_dyn_pt, proto_ps)
                else  -- replace this proto with old proto on old payload type
                    payload_type_table:add(old_dyn_pt, old_dissector)
                end
            end
            old_dyn_pt = prefs.dyn_pt  -- save current payload type's dissector
            
            if string.len(prefs.dyn_pt) > 0 then
                dyn_pt_number = tonumber(prefs.dyn_pt)
                old_dissector = payload_type_table:get_dissector(dyn_pt_number)
                payload_type_table:add(dyn_pt_number, proto_ps)
            end
        end
    end
end