/* packet-smpte-291-vanc.c

 * SMPTE ST 291 ancillary-data parsing and built-in VANC application dissectors.

 *

 * Built-in application payloads implemented in this source file:

 *   SMPTE ST 12-2, SMPTE ST 2010, SMPTE ST 2016-3, SMPTE ST 2031,

 *   SMPTE ST 334-2, and Free TV Australia OP-47 / SMPTE RDD 8.

 *

 * Copyright (c) 2026, Devin Heitmueller <dheitmueller@ltnglobal.com>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <string.h>

#include <epan/expert.h>

#include <epan/packet.h>

#include <epan/reassemble.h>

#include <epan/tfs.h>

#include <wsutil/array.h>

#include <wsutil/bitswap.h>

#include "packet-smpte-291-vanc.h"

/* Protocol, field, subtree, expert, and dissector declarations */

/* SMPTE ST 291 common declarations */

static int proto_st291;

static int hf_st291_did;

static int hf_st291_sdid;

static int hf_st291_dbn;

static dissector_table_t st291_did_sdid_table;

typedef struct {

    tvbuff_t *full_tvb;

    tvbuff_t *byte_tvb;

} st291_vanc_udw_t;

/* SMPTE ST 12-2 declarations */

static int proto_st12_2;

static int hf_st12_2_timecode;

static int hf_st12_2_frame_units;

static int hf_st12_2_frame_tens;

static int hf_st12_2_second_units;

static int hf_st12_2_second_tens;

static int hf_st12_2_minute_units;

static int hf_st12_2_minute_tens;

static int hf_st12_2_hour_units;

static int hf_st12_2_hour_tens;

static int hf_st12_2_binary_group_1;

static int hf_st12_2_binary_group_2;

static int hf_st12_2_binary_group_3;

static int hf_st12_2_binary_group_4;

static int hf_st12_2_binary_group_5;

static int hf_st12_2_binary_group_6;

static int hf_st12_2_binary_group_7;

static int hf_st12_2_binary_group_8;

static int hf_st12_2_flag_bit_10;

static int hf_st12_2_flag_bit_11;

static int hf_st12_2_flag_bit_27;

static int hf_st12_2_flag_bit_43;

static int hf_st12_2_flag_bit_58;

static int hf_st12_2_flag_bit_59;

static int hf_st12_2_payload_type;

static int hf_st12_2_vitc;

static int hf_st12_2_vitc_line_sel;

static int hf_st12_2_vitc_line_dup;

static int hf_st12_2_vitc_validity;

static int hf_st12_2_vitc_process;

static int ett_st12_2;

static int ett_st12_2_timecode;

static int ett_st12_2_vitc;

static expert_field ei_st12_2_bad_length = EI_INIT;

static dissector_handle_t st12_2_handle;

/* SMPTE ST 2010 declarations */

static int proto_st2010;

static int hf_st2010_payload_descriptor;

static int hf_st2010_reserved;

static int hf_st2010_version;

static int hf_st2010_continued_pkt;

static int hf_st2010_following_pkt;

static int hf_st2010_duplicate_msg;

static int hf_st2010_payload;

static int hf_st2010_fragments;

static int hf_st2010_fragment;

static int hf_st2010_fragment_overlap;

static int hf_st2010_fragment_overlap_conflict;

static int hf_st2010_fragment_multiple_tails;

static int hf_st2010_fragment_too_long_fragment;

static int hf_st2010_fragment_error;

static int hf_st2010_fragment_count;

static int hf_st2010_reassembled_in;

static int hf_st2010_reassembled_length;

static int hf_st2010_reassembled_data;

static int ett_st2010;

static int ett_st2010_fragment;

static int ett_st2010_fragments;

static expert_field ei_st2010_bad_version = EI_INIT;

static expert_field ei_st2010_reserved_bits = EI_INIT;

static expert_field ei_st2010_orphan_fragment = EI_INIT;

static expert_field ei_st2010_overlapping_message = EI_INIT;

static expert_field ei_st2010_empty_payload = EI_INIT;

static dissector_handle_t st2010_handle;

static dissector_table_t st2010_payload_table;

static reassembly_table st2010_reassembly_table;

/* SMPTE ST 2016-3 declarations */

static int proto_st2016_3;

static int hf_st2016_3_afd_byte;

static int hf_st2016_3_afd_code;

static int hf_st2016_3_afd_ar;

static int hf_st2016_3_afd_reserved;

static int hf_st2016_3_reserved_1;

static int hf_st2016_3_reserved_2;

static int hf_st2016_3_bar_flags;

static int hf_st2016_3_bar_top;

static int hf_st2016_3_bar_bottom;

static int hf_st2016_3_bar_left;

static int hf_st2016_3_bar_right;

static int hf_st2016_3_bar_reserved;

static int hf_st2016_3_bar_value_1;

static int hf_st2016_3_bar_value_1_marker;

static int hf_st2016_3_bar_value_1_data;

static int hf_st2016_3_bar_value_2;

static int hf_st2016_3_bar_value_2_marker;

static int hf_st2016_3_bar_value_2_data;

static int hf_st2016_3_bar_value_1_meaning;

static int hf_st2016_3_bar_value_2_meaning;

static int ett_st2016_3;

static int ett_st2016_3_afd;

static int ett_st2016_3_bar_flags;

static int ett_st2016_3_bar_value_1;

static int ett_st2016_3_bar_value_2;

static expert_field ei_st2016_3_bad_length;

static expert_field ei_st2016_3_afd_reserved;

static expert_field ei_st2016_3_reserved_udw;

static expert_field ei_st2016_3_bar_reserved;

static expert_field ei_st2016_3_bar_flags_invalid;

static expert_field ei_st2016_3_bar_marker;

static dissector_handle_t st2016_3_handle;

/* SMPTE ST 334-2 declarations */

static int proto_st334_2;

static int hf_st334_2_cdp_identifier;

static int hf_st334_2_cdp_length;

static int hf_st334_2_frame_rate;

static int hf_st334_2_header_reserved;

static int hf_st334_2_time_code_present;

static int hf_st334_2_ccdata_present;

static int hf_st334_2_svcinfo_present;

static int hf_st334_2_svc_info_start;

static int hf_st334_2_svc_info_change;

static int hf_st334_2_svc_info_complete;

static int hf_st334_2_caption_service_active;

static int hf_st334_2_header_reserved_bit;

static int hf_st334_2_header_sequence_counter;

static int hf_st334_2_section_id;

static int hf_st334_2_timecode;

static int hf_st334_2_tc_field_flag;

static int hf_st334_2_drop_frame_flag;

static int hf_st334_2_cc_count;

static int hf_st334_2_cc_marker_bits;

static int hf_st334_2_cc_valid;

static int hf_st334_2_cc_type;

static int hf_st334_2_cc_data_1;

static int hf_st334_2_cc_data_2;

static int hf_st334_2_dtvcc_data;

static int hf_st334_2_svc_reserved;

static int hf_st334_2_svc_info_start_section;

static int hf_st334_2_svc_info_change_section;

static int hf_st334_2_svc_info_complete_section;

static int hf_st334_2_svc_count;

static int hf_st334_2_csn_reserved;

static int hf_st334_2_csn_size;

static int hf_st334_2_csn_reserved_2;

static int hf_st334_2_caption_service_number;

static int hf_st334_2_service_data;

static int hf_st334_2_service_language;

static int hf_st334_2_service_digital_cc;

static int hf_st334_2_service_digital_reserved;

static int hf_st334_2_service_line21_reserved;

static int hf_st334_2_service_line21_field;

static int hf_st334_2_service_descriptor_number;

static int hf_st334_2_service_easy_reader;

static int hf_st334_2_service_wide_aspect_ratio;

static int hf_st334_2_service_reserved_14;

static int hf_st334_2_future_length;

static int hf_st334_2_future_data;

static int hf_st334_2_footer_sequence_counter;

static int hf_st334_2_packet_checksum;

static int hf_st334_2_checksum_calculated;

static int ett_st334_2;

static int ett_st334_2_header;

static int ett_st334_2_timecode;

static int ett_st334_2_ccdata;

static int ett_st334_2_cc_construct;

static int ett_st334_2_svcinfo;

static int ett_st334_2_service;

static int ett_st334_2_service_data;

static int ett_st334_2_future;

static int ett_st334_2_footer;

static expert_field ei_st334_2_bad_identifier;

static expert_field ei_st334_2_bad_length;

static expert_field ei_st334_2_bad_reserved;

static expert_field ei_st334_2_bad_section_order;

static expert_field ei_st334_2_duplicate_section;

static expert_field ei_st334_2_missing_section;

static expert_field ei_st334_2_cc_count;

static expert_field ei_st334_2_bad_marker;

static expert_field ei_st334_2_sequence_mismatch;

static expert_field ei_st334_2_bad_checksum;

static expert_field ei_st334_2_truncated;

static dissector_handle_t st334_2_handle;

/* SMPTE ST 2031 declarations */

static int proto_st2031;

static int hf_st2031_data_identifier;

static int hf_st2031_data_unit_id;

static int hf_st2031_data_unit_length;

static int hf_st2031_field_parity;

static int hf_st2031_line_offset;

static int hf_st2031_framing_code;

static int hf_st2031_magazine_hamming;

static int hf_st2031_magazine;

static int hf_st2031_packet_number_hamming;

static int hf_st2031_packet_number;

static int hf_st2031_page_units_hamming;

static int hf_st2031_page_units;

static int hf_st2031_page_tens_hamming;

static int hf_st2031_page_tens;

static int hf_st2031_data_string;

static int hf_st2031_textdata_array;

static int hf_st2031_erase_page;

static int hf_st2031_newsflash;

static int hf_st2031_subtitle;

static int hf_st2031_suppress_header;

static int hf_st2031_update_indicator;

static int hf_st2031_interrupted_sequence;

static int hf_st2031_inhibit_display;

static int hf_st2031_magazine_serial;

static int hf_st2031_character_set;

static int hf_st2031_tt_control;

static int ett_st2031;

static dissector_handle_t st2031_handle;

/* OP-47 / SMPTE RDD 8 declarations */

static int proto_op47;

static int hf_op47_sdp_identifier;

static int hf_op47_sdp_length;

static int hf_op47_sdp_format_code;

static int hf_op47_sdp_adaption_header;

static int hf_op47_sdp_pkt_desc_b;

static int hf_op47_clock_runin;

static int hf_op47_framing_code;

static int hf_op47_magazine_hamming;

static int hf_op47_magazine;

static int hf_op47_packet_number_hamming;

static int hf_op47_packet_number;

static int hf_op47_page_units_hamming;

static int hf_op47_page_units;

static int hf_op47_page_tens_hamming;

static int hf_op47_page_tens;

static int hf_op47_data_string;

static int hf_op47_textdata_array;

static int hf_op47_erase_page;

static int hf_op47_newsflash;

static int hf_op47_subtitle;

static int hf_op47_suppress_header;

static int hf_op47_update_indicator;

static int hf_op47_interrupted_sequence;

static int hf_op47_inhibit_display;

static int hf_op47_magazine_serial;

static int hf_op47_character_set;

static int hf_op47_tt_control;

static int ett_op47;

static int ett_op47_wst;

static dissector_handle_t op47_handle;

/* ST 291 Type 2 DID/SDID keys used by the built-in VANC dissectors. */

#define ST12_2_DID_SDID_KEY   0x6060

#define ST2010_DID_SDID_KEY   0x4107

#define ST2016_3_DID_SDID_KEY 0x4105

#define ST334_2_DID_SDID_KEY  0x6101

#define ST334_2_CDP_IDENTIFIER 0x9669

#define ST2031_DID_SDID_KEY   0x4108

#define OP47_DID_SDID_KEY     0x4302

#define ST2010_PAYLOAD_SCTE104 0

/*

 * SMPTE ST 291-1 ancillary-data core and DID/SDID dispatch

 */

/*

 * Registered SMPTE ST 291 DID/SDID assignments.

 *

 * SMPTE ST 291-1:2011, Sec. 4 assigns DID values through the SMPTE

 * Registration Authority; Sec. 5.1 defines Type 1 versus Type 2 packets.

 *

 * Source: SMPTE Registration Authority, "Data Identification Word

 * Assignments for Registered DIDs", downloaded from:

 * https://www.smpte-ra.org/smpte-ancillary-data-smpte-st-291

 *

 * The register contained 81 assignments when reviewed on 2026-09-05.

 * Keep this table synchronized with the SMPTE RA register rather than with

 * transport-specific dissectors such as ST 2110-40 or ST 2038.

 */

typedef struct {

    uint8_t did;

    uint8_t sdid;

    const char *description;

} st291_did_sdid_entry_t;

typedef struct {

    uint8_t did;

    const char *description;

} st291_did_entry_t;

/* Type 2 identities: SMPTE ST 291-1:2011, Sec. 5.1 uses DID + SDID. */

static const st291_did_sdid_entry_t st291_did_sdid_assignments[] = {

    { 0x08, 0x08, "SMPTE ST 353: MPEG recoding data, VANC space" },

    { 0x08, 0x0c, "SMPTE ST 353: MPEG recoding data, HANC space" },

    { 0x40, 0x01, "SMPTE ST 305: SDTI transport in active frame space" },

    { 0x40, 0x02, "SMPTE ST 348: HD-SDTI transport in active frame space" },

    { 0x40, 0x04, "SMPTE ST 427: Link Encryption Message 1" },

    { 0x40, 0x05, "SMPTE ST 427: Link Encryption Message 2" },

    { 0x40, 0x06, "SMPTE ST 427: Link Encryption Metadata" },

    { 0x41, 0x01, "SMPTE ST 352: Payload Identification, HANC space" },

    { 0x41, 0x05, "SMPTE ST 2016-3: AFD and Bar Data" },

    { 0x41, 0x06, "SMPTE ST 2016-4: Pan-Scan Data" },

    { 0x41, 0x07, "SMPTE ST 2010: ANSI/SCTE 104 messages" },

    { 0x41, 0x08, "SMPTE ST 2031: DVB/SCTE VBI data" },

    { 0x41, 0x09, "SMPTE ST 2056: MPEG TS packets in VANC" },

    { 0x41, 0x0a, "SMPTE ST 2068: Stereoscopic 3D Frame Compatible Packing and Signaling" },

    { 0x41, 0x0b, "SMPTE ST 2064-2: Lip Sync data as specified by ST 2064-1" },

    { 0x41, 0x0c, "SMPTE ST 2108-1: Extended HDR/WCG for SDI" },

    { 0x41, 0x0d, "SMPTE ST 2108-2: Vertical Ancillary Data Mapping of KLV Formatted HDR/WCG Metadata" },

    { 0x43, 0x01, "ITU-R BT.1685: Structure of inter-station control data conveyed by ancillary data packets" },

    { 0x43, 0x02, "SMPTE RDD 8: Subtitling Distribution packet (SDP)" },

    { 0x43, 0x03, "SMPTE RDD 8: Transport of ANC packet in an ANC Multipacket" },

    { 0x43, 0x04, "ARIB TR-B29: Metadata to monitor errors of audio and video signals on a broadcasting chain" },

    { 0x43, 0x05, "SMPTE RDD 18: Acquisition Metadata Sets for Video Camera Parameters" },

    { 0x44, 0x04, "SMPTE RP 214: KLV Metadata transport in VANC space" },

    { 0x44, 0x14, "SMPTE RP 214: KLV Metadata transport in HANC space" },

    { 0x44, 0x44, "SMPTE RP 223: Packing UMID and Program Identification Label Data into ST 291 ancillary data packets" },

    { 0x45, 0x01, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x02, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x03, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x04, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x05, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x06, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x07, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x08, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x45, 0x09, "SMPTE ST 2020-1: Compressed Audio Metadata" },

    { 0x46, 0x01, "SMPTE ST 2051: Two Frame Marker in HANC" },

    { 0x50, 0x01, "SMPTE RDD 8: WSS data" },

    { 0x51, 0x01, "SMPTE RP 215: Film Codes in VANC space" },

    { 0x60, 0x60, "SMPTE ST 12-2: Ancillary Time Code" },

    { 0x60, 0x61, "SMPTE ST 12-3: Time Code for High Frame Rate Signals" },

    { 0x60, 0x62, "SMPTE ST 2103: Generic Time Label" },

    { 0x61, 0x01, "SMPTE ST 334-1: EIA 708B Data mapping into VANC space" },

    { 0x61, 0x02, "SMPTE ST 334-1: EIA 608 Data mapping into VANC space" },

    { 0x62, 0x01, "SMPTE RP 207: Program Description in VANC space" },

    { 0x62, 0x02, "SMPTE ST 334-1: Data broadcast (DTV) in VANC space" },

    { 0x62, 0x03, "SMPTE RP 208: VBI Data in VANC space" },

    { 0x64, 0x64, "SMPTE RP 196 (withdrawn): Time Code in HANC space" },

    { 0x64, 0x7f, "SMPTE RP 196 (withdrawn): VITC in HANC space" },

};

/* Type 1 identities: SMPTE ST 291-1:2011, Sec. 5.1 uses DID + DBN. */

static const st291_did_entry_t st291_did_assignments[] = {

    { 0x00, "SMPTE ST 291: Undefined data deleted (deprecated)" },

    { 0x80, "SMPTE ST 291: Packet marked for deletion" },

    { 0x84, "SMPTE ST 291: End packet deleted (deprecated)" },

    { 0x88, "SMPTE ST 291: Start packet deleted (deprecated)" },

    { 0xa0, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 8 Control packet" },

    { 0xa1, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 7 Control packet" },

    { 0xa2, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 6 Control packet" },

    { 0xa3, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 5 Control packet" },

    { 0xa4, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 8" },

    { 0xa5, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 7" },

    { 0xa6, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 6" },

    { 0xa7, "SMPTE ST 299-2: Audio data in HANC space (3G), Group 5" },

    { 0xe0, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe1, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe2, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe3, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe4, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe5, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe6, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xe7, "SMPTE ST 299-1: Audio data in HANC space (HDTV)" },

    { 0xec, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xed, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xee, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xef, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xf0, "SMPTE ST 315: Camera position (HANC or VANC space)" },

    { 0xf4, "SMPTE RP 165: Error Detection and Handling (HANC space)" },

    { 0xf8, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xf9, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xfa, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xfb, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xfc, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xfd, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xfe, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

    { 0xff, "SMPTE ST 272: Audio data in HANC space (SDTV)" },

};

static const char *

st291_lookup_did(uint8_t did)

{

    unsigned i;

    for (i = 0; i < array_length(st291_did_assignments); i++) {

        if (st291_did_assignments[i].did == did)

            return st291_did_assignments[i].description;

    }

    return NULL;

}

static const char *

st291_lookup_did_sdid(uint8_t did, uint8_t sdid)

{

    unsigned i;

    for (i = 0; i < array_length(st291_did_sdid_assignments); i++) {

        if (st291_did_sdid_assignments[i].did == did &&

            st291_did_sdid_assignments[i].sdid == sdid)

            return st291_did_sdid_assignments[i].description;

    }

    return NULL;

}

static bool

st291_id_word_parity_ok(uint16_t word)

{

    unsigned ones = 0;

    unsigned bit;

    uint8_t data = word & 0x00ff;

    unsigned b8 = (word >> 8) & 1U;

    unsigned b9 = (word >> 9) & 1U;

    for (bit = 0; bit < 8; bit++)

        ones += (data >> bit) & 1U;

    return (((ones + b8) & 1U) == 0) && (b9 == (b8 ^ 1U));

}

bool

st291_vanc_packet_from_words(tvbuff_t *parent_tvb, packet_info *pinfo,

                             const uint16_t *words, unsigned word_count,

                             st291_vanc_packet_t *packet)

{

    uint16_t *normalized_words;

    uint8_t *packed_data;

    unsigned expected_words;

    unsigned packed_length;

    unsigned i;

    DISSECTOR_ASSERT(parent_tvb != NULL);

    DISSECTOR_ASSERT(pinfo != NULL);

    DISSECTOR_ASSERT(words != NULL || word_count == 0);

    DISSECTOR_ASSERT(packet != NULL);

    memset(packet, 0, sizeof(*packet));

    if (word_count < 4)

        return false;

    expected_words = 4U + (words[2] & 0x00ff);

    if (word_count < expected_words)

        return false;

    normalized_words = wmem_alloc_array(pinfo->pool, uint16_t, expected_words);

    for (i = 0; i < expected_words; i++)

        normalized_words[i] = words[i] & 0x03ff;

    packet->parent_tvb = parent_tvb;

    packet->words = normalized_words;

    packet->word_count = expected_words;

    packet->did = normalized_words[0] & 0x00ff;

    packet->sdid_or_dbn = normalized_words[1] & 0x00ff;

    packet->data_count = normalized_words[2] & 0x00ff;

    packet->checksum = normalized_words[3 + packet->data_count];

    packet->did_parity_ok = st291_id_word_parity_ok(normalized_words[0]);

    packet->second_word_parity_ok = st291_id_word_parity_ok(normalized_words[1]);

    packet->data_count_parity_ok = st291_id_word_parity_ok(normalized_words[2]);

    packet->checksum_calculated = 0;

    for (i = 0; i < 3U + packet->data_count; i++) {

        packet->checksum_calculated =

            (packet->checksum_calculated + (normalized_words[i] & 0x01ff)) &

            0x01ff;

    }

    if ((packet->checksum_calculated & 0x0100) == 0)

        packet->checksum_calculated |= 0x0200;

    packet->checksum_ok = packet->checksum == packet->checksum_calculated;

    /* Word-oriented transports do not necessarily have a contiguous source

     * range (for example, one component of an interleaved SDI raster). Build

     * a canonical packed representation so the shared renderer can still

     * display the logical 10-bit UDW sequence. */

    if (packet->data_count != 0) {

        packed_length = (packet->data_count * 10 + 7) / 8;

        packed_data = wmem_alloc0(pinfo->pool, packed_length);

        for (i = 0; i < packet->data_count; i++) {

            uint16_t word = normalized_words[3 + i];

            unsigned bit;

            for (bit = 0; bit < 10; bit++) {

                if ((word & (1U << (9 - bit))) != 0) {

                    unsigned packed_bit = i * 10 + bit;

                    packed_data[packed_bit / 8] |= 1U << (7 - packed_bit % 8);

                }

            }

        }

        packet->packed_udw_tvb = tvb_new_child_real_data(parent_tvb,

                                                          packed_data,

                                                          packed_length,

                                                          packed_length);

    }

    return true;

}

bool

st291_vanc_packet_from_packed(tvbuff_t *tvb, packet_info *pinfo,

                              unsigned bit_offset, unsigned available_bits,

                              st291_vanc_packet_t *packet)

{

    uint16_t header_words[3];

    uint16_t *words;

    unsigned required_bits;

    unsigned udw_bit_offset;

    unsigned word_count;

    unsigned byte_offset;

    unsigned byte_length;

    unsigned i;

    DISSECTOR_ASSERT(tvb != NULL);

    DISSECTOR_ASSERT(pinfo != NULL);

    DISSECTOR_ASSERT(packet != NULL);

    memset(packet, 0, sizeof(*packet));

    if (available_bits < 30)

        return false;

    for (i = 0; i < array_length(header_words); i++)

        header_words[i] = tvb_get_bits16(tvb, bit_offset + i * 10, 10,

                                         ENC_BIG_ENDIAN);

    word_count = 4U + (header_words[2] & 0x00ff);

    required_bits = word_count * 10;

    if (required_bits > available_bits) {

        /* Preserve the decoded header so the transport can distinguish a

         * truncated ST 291 header from a complete header whose declared

         * packet extends beyond the transport boundary. */

        packet->did = header_words[0] & 0x00ff;

        packet->sdid_or_dbn = header_words[1] & 0x00ff;

        packet->data_count = header_words[2] & 0x00ff;

        packet->word_count = word_count;

        return false;

    }

    words = wmem_alloc_array(pinfo->pool, uint16_t, word_count);

    for (i = 0; i < word_count; i++)

        words[i] = tvb_get_bits16(tvb, bit_offset + i * 10, 10,

                                  ENC_BIG_ENDIAN);

    if (!st291_vanc_packet_from_words(tvb, pinfo, words, word_count, packet))

        return false;

    if (packet->data_count != 0) {

        udw_bit_offset = bit_offset + 30;

        byte_offset = (unsigned)(udw_bit_offset / 8);

        packet->packed_udw_bit_offset = (unsigned)(udw_bit_offset % 8);

        byte_length = (packet->packed_udw_bit_offset +

                       packet->data_count * 10 + 7) / 8;

        packet->packed_udw_tvb = tvb_new_subset_length(tvb, byte_offset,

                                                        byte_length);

    }

    return true;

}

/* Keep the canonical full-width and compatibility byte TVBs here so every

 * ST 291 transport presents the same subdissector interface. */

static void

st291_vanc_create_udw_tvbs(tvbuff_t *parent_tvb, packet_info *pinfo,

                           const uint16_t *udw_words, unsigned udw_count,

                           st291_vanc_udw_t *udw)

{

    uint8_t *full_data;

    uint8_t *payload_data;

    unsigned i;

    DISSECTOR_ASSERT(udw != NULL);

    DISSECTOR_ASSERT(udw_words != NULL || udw_count == 0);

    full_data = wmem_alloc(pinfo->pool, MAX(2U, udw_count * 2U));

    payload_data = wmem_alloc(pinfo->pool, MAX(1U, udw_count));

    for (i = 0; i < udw_count; i++) {

        uint16_t word = udw_words[i] & 0x03ff;

        full_data[i * 2] = (uint8_t)(word >> 8);

        full_data[i * 2 + 1] = (uint8_t)word;

        payload_data[i] = (uint8_t)word;

    }

    udw->full_tvb = tvb_new_child_real_data(parent_tvb, full_data,

                                             udw_count * 2, udw_count * 2);

    udw->byte_tvb = tvb_new_child_real_data(parent_tvb, payload_data,

                                             udw_count, udw_count);

}

bool

st291_vanc_dissect_packet(const st291_vanc_packet_t *packet,

                          packet_info *pinfo, proto_tree *tree,

                          proto_item *payload_item _U_,

                          const st291_vanc_dissector_data_t *data)

{

    st291_vanc_udw_t udw;

    st291_vanc_dissector_data_t subdissector_data;

    uint8_t dispatch_sdid;

    DISSECTOR_ASSERT(packet != NULL);

    DISSECTOR_ASSERT(data != NULL);

    st291_vanc_create_udw_tvbs(packet->parent_tvb, pinfo, packet->words + 3,

                               packet->data_count, &udw);

    if (packet->data_count != 0)

        add_new_data_source(pinfo, udw.byte_tvb, "ST 291 UDW Array");

    subdissector_data = *data;

    subdissector_data.full_udw_tvb = udw.full_tvb;

    dispatch_sdid = (packet->did & 0x80U) != 0 ? 0x00 : packet->sdid_or_dbn;

    return dissector_try_uint_with_data(

        st291_did_sdid_table,

        ((uint32_t)packet->did << 8) | dispatch_sdid,

        udw.byte_tvb, pinfo, tree, true, &subdissector_data);

}

/* SMPTE ST 291-1:2011, Secs. 5.1-5.2 -- DID/SDID/DBN on-wire identity fields. */

proto_item *

st291_tree_add_did(proto_tree *tree, tvbuff_t *tvb,

                   int offset, int length, uint8_t did)

{

    return proto_tree_add_uint(tree, hf_st291_did, tvb, offset, length, did);

}

proto_item *

st291_tree_add_sdid(proto_tree *tree, tvbuff_t *tvb,

                    int offset, int length, uint8_t did _U_, uint8_t sdid)

{

    return proto_tree_add_uint(tree, hf_st291_sdid, tvb, offset, length, sdid);

}

/* SMPTE ST 291-1:2011, Sec. 5.1: bit b7 of the DID distinguishes the

 * Type 1 (DBN) and Type 2 (SDID) identity forms used for the lookup. */

void

st291_append_packet_description(proto_item *item, uint8_t did, uint8_t sdid_or_dbn)

{

    const char *description;

    if ((did & 0x80U) != 0)

        description = st291_lookup_did(did);

    else

        description = st291_lookup_did_sdid(did, sdid_or_dbn);

    if (description != NULL)

        proto_item_append_text(item, ": %s", description);

}

proto_item *

st291_tree_add_dbn(proto_tree *tree, tvbuff_t *tvb,

                   int offset, int length, uint8_t dbn)

{

    return proto_tree_add_uint(tree, hf_st291_dbn, tvb, offset, length, dbn);

}

/* SMPTE ST 291-1:2011, Secs. 5.1-5.2 define DID, SDID and DBN.

 * The st291.did_sdid table below is Wireshark-only dispatch metadata. */

void

proto_register_st291(void)

{

    static hf_register_info hf[] = {

        { &hf_st291_did,

          { "Data ID", "st291.did", FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL } },

        { &hf_st291_sdid,

          { "Secondary Data ID", "st291.sdid", FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL } },

        { &hf_st291_dbn,

          { "Data Block Number", "st291.dbn", FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL } },

    };

    proto_st291 = proto_register_protocol(

        "SMPTE ST 291 Ancillary Data", "ST 291", "st291");

    proto_register_field_array(proto_st291, hf, array_length(hf));

    /*

     * Public extension point for ST 291 application payload dissectors.

     * Native and Lua dissectors can register DID/SDID keys here for

     * additional VANC payload formats.

     */

    st291_did_sdid_table = register_dissector_table(

        "st291.did_sdid", "SMPTE ST 291 DID/SDID",

        proto_st291, FT_UINT16, BASE_HEX);

}

/*

 * SMPTE ST 12-2 time code in ancillary data

 */

/* SMPTE ST 12-2:2014, Sec. 6.2.1, Table 2 -- DBB1 payload type. */

static const value_string st12_2_payload_type_vals[] = {

    { 0x00, "Linear time code (ATC_LTC)" },

    { 0x01, "Vertical interval time code #1 (ATC_VITC1)" },

    { 0x02, "Vertical interval time code #2 (ATC_VITC2)" },

    { 0x03, "User defined" },

    { 0x04, "User defined" },

    { 0x05, "User defined" },

    { 0x06, "Film data block (transferred from reader)" },

    { 0x07, "Production data block (transferred from reader)" },

    { 0x7D, "Video tape data block (locally generated)" },

    { 0x7E, "Film data block (locally generated)" },

    { 0x7F, "Production data block (locally generated)" },

    { 0, NULL }

};

/* SMPTE ST 12-2:2014, Sec. 6.2.2, Tables 3 and 5 -- DBB2 validity/process bits. */

static const value_string st12_2_vitc_validity_vals[] = {

    { 0, "No time code error received or locally generated time code address" },

    { 1, "Transmitted time code interpolated from previous time code (received a time code error)" },

    { 0, NULL }

};

static const value_string st12_2_vitc_process_vals[] = {

    { 0, "Binary groups in time code data stream are processed to compensate for latency" },

    { 1, "Binary groups in time code data stream are only retransmitted (no delay compensation)" },

    { 0, NULL }

};

/*

 * SMPTE ST 12-2:2014, Sec. 6.3, Table 6 maps the 64 information bits

 * defined by SMPTE ST 12-1 into UDW 1 through UDW 16.  The time address

 * is BCD; the intervening nibbles are the eight binary groups.  The six

 * remaining positions are ST 12-1 flag bits whose meaning depends on the

 * television system/frame rate (ST 12-1:2014, Sec. 8.3 and Tables 1-3).

 */

static int

dissect_st12_2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

    const st291_vanc_dissector_data_t *st291_data =

        (const st291_vanc_dissector_data_t *)data;

    proto_tree *top_tree =

        st291_data && st291_data->top_tree ? st291_data->top_tree : tree;

    proto_item *ti;

    proto_tree *st12_tree;

    proto_tree *time_tree;

    proto_tree *vitc_tree;

    uint8_t dbb1 = 0;

    uint8_t dbb2 = 0;

    uint8_t frame_units;

    uint8_t frame_tens;

    uint8_t second_units;

    uint8_t second_tens;

    uint8_t minute_units;

    uint8_t minute_tens;

    uint8_t hour_units;

    uint8_t hour_tens;

    uint8_t frames;

    uint8_t seconds;

    uint8_t minutes;

    uint8_t hours;

    bool drop_frame;

    char time_str[16];

    unsigned x;

    ti = proto_tree_add_item(top_tree, proto_st12_2, tvb, 0,

                             tvb_captured_length(tvb), ENC_NA);

    st12_tree = proto_item_add_subtree(ti, ett_st12_2);

    if (tvb_captured_length(tvb) < 16) {

        expert_add_info_format(pinfo, ti, &ei_st12_2_bad_length,

                               "ST 12-2 requires at least 16 UDW bytes; packet contains %u",

                               tvb_captured_length(tvb));

        return tvb_captured_length(tvb);

    }

    /*

     * SMPTE ST 12-2:2014, Sec. 6.3, Table 6 maps the 64 information

     * bits defined by SMPTE ST 12-1 into UDW 1 through UDW 16.

     *

     * The time-address digits are BCD:

     *   UDW 1/3   -- frame units/tens

     *   UDW 5/7   -- second units/tens

     *   UDW 9/11  -- minute units/tens

     *   UDW 13/15 -- hour units/tens

     *

     * ST 12-2 Sec. 6.1.2 defines b4 as the least-significant bit of

     * each four-bit information group.

     */

    frame_units  = (tvb_get_uint8(tvb, 0)  >> 4) & 0x0f;

    frame_tens   = (tvb_get_uint8(tvb, 2)  >> 4) & 0x03;

    second_units = (tvb_get_uint8(tvb, 4)  >> 4) & 0x0f;

    second_tens  = (tvb_get_uint8(tvb, 6)  >> 4) & 0x07;

    minute_units = (tvb_get_uint8(tvb, 8)  >> 4) & 0x0f;

    minute_tens  = (tvb_get_uint8(tvb, 10) >> 4) & 0x07;

    hour_units   = (tvb_get_uint8(tvb, 12) >> 4) & 0x0f;

    hour_tens    = (tvb_get_uint8(tvb, 14) >> 4) & 0x03;

    frames  = frame_tens * 10 + frame_units;

    seconds = second_tens * 10 + second_units;

    minutes = minute_tens * 10 + minute_units;

    hours   = hour_tens * 10 + hour_units;

    /*

     * SMPTE ST 12-2:2014, Sec. 6.3, Table 6 maps ST 12-1 bit 10 to

     * UDW 3 b6.  SMPTE ST 12-1:2014, Table 3 identifies bit 10 as

     * the drop-frame flag for the applicable 30-frame systems.

     */

    drop_frame = (tvb_get_uint8(tvb, 2) & 0x40) != 0;

    snprintf(time_str, sizeof(time_str), "%02u:%02u:%02u%c%02u",

             hours, minutes, seconds, drop_frame ? ';' : ':', frames);

    /*

     * This row is a human-readable representation of the 64 information

     * bits below.  It spans the actual UDW bytes rather than being marked

     * generated, so selecting it highlights the complete ATC data block.

     */

    ti = proto_tree_add_string(st12_tree, hf_st12_2_timecode, tvb, 0, 16, time_str);

    time_tree = proto_item_add_subtree(ti, ett_st12_2_timecode);

    /*

     * The BCD digit fields below are the actual on-wire nibbles from

     * ST 12-2:2014, Sec. 6.3, Table 6.  Their hf masks select the

     * corresponding b4-b7 positions in each UDW byte.

     */

    /*

     * SMPTE ST 12-2:2014, Sec. 6.3, Table 6.  Present the fields in

     * UDW order so the protocol tree follows the packet layout directly.

     */

    /* UDW 1: units of frames */

    proto_tree_add_item(time_tree, hf_st12_2_frame_units, tvb, 0, 1, ENC_BIG_ENDIAN);

    /* UDW 2: binary group 1 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_1, tvb, 1, 1, ENC_BIG_ENDIAN);

    /* UDW 3: tens of frames, ST 12-1 flag bits 10 and 11 */

    proto_tree_add_item(time_tree, hf_st12_2_frame_tens, tvb, 2, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_10, tvb, 2, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_11, tvb, 2, 1, ENC_BIG_ENDIAN);

    /* UDW 4: binary group 2 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_2, tvb, 3, 1, ENC_BIG_ENDIAN);

    /* UDW 5: units of seconds */

    proto_tree_add_item(time_tree, hf_st12_2_second_units, tvb, 4, 1, ENC_BIG_ENDIAN);

    /* UDW 6: binary group 3 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_3, tvb, 5, 1, ENC_BIG_ENDIAN);

    /* UDW 7: tens of seconds, ST 12-1 flag bit 27 */

    proto_tree_add_item(time_tree, hf_st12_2_second_tens, tvb, 6, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_27, tvb, 6, 1, ENC_BIG_ENDIAN);

    /* UDW 8: binary group 4 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_4, tvb, 7, 1, ENC_BIG_ENDIAN);

    /* UDW 9: units of minutes */

    proto_tree_add_item(time_tree, hf_st12_2_minute_units, tvb, 8, 1, ENC_BIG_ENDIAN);

    /* UDW 10: binary group 5 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_5, tvb, 9, 1, ENC_BIG_ENDIAN);

    /* UDW 11: tens of minutes, ST 12-1 flag bit 43 */

    proto_tree_add_item(time_tree, hf_st12_2_minute_tens, tvb, 10, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_43, tvb, 10, 1, ENC_BIG_ENDIAN);

    /* UDW 12: binary group 6 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_6, tvb, 11, 1, ENC_BIG_ENDIAN);

    /* UDW 13: units of hours */

    proto_tree_add_item(time_tree, hf_st12_2_hour_units, tvb, 12, 1, ENC_BIG_ENDIAN);

    /* UDW 14: binary group 7 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_7, tvb, 13, 1, ENC_BIG_ENDIAN);

    /* UDW 15: tens of hours, ST 12-1 flag bits 58 and 59 */

    proto_tree_add_item(time_tree, hf_st12_2_hour_tens, tvb, 14, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_58, tvb, 14, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(time_tree, hf_st12_2_flag_bit_59, tvb, 14, 1, ENC_BIG_ENDIAN);

    /* UDW 16: binary group 8 */

    proto_tree_add_item(time_tree, hf_st12_2_binary_group_8, tvb, 15, 1, ENC_BIG_ENDIAN);

    /*

     * SMPTE ST 12-2:2014, Secs. 6.2.1-6.2.2, Tables 2-3.

     * DBB1 is assembled from b4 of UDW 1-8; DBB2 from b4 of UDW 9-16.

     * These bytes are logical fields spread across multiple UDWs, so they

     * are shown as generated aggregate values.

     */

    for (x = 0; x < 8; x++) {

        dbb1 |= tvb_get_bits8(tvb, (x) * 8 + 4, 1) << x;

        dbb2 |= tvb_get_bits8(tvb, (8 + x) * 8 + 4, 1) << x;

    }

    ti = proto_tree_add_uint(st12_tree, hf_st12_2_payload_type, tvb, 0, 0, dbb1);

    proto_item_set_generated(ti);

    ti = proto_tree_add_uint(st12_tree, hf_st12_2_vitc, tvb, 0, 0, dbb2);

    proto_item_set_generated(ti);

    if (dbb1 == 0x01 || dbb1 == 0x02) {

        vitc_tree = proto_item_add_subtree(ti, ett_st12_2_vitc);

        ti = proto_tree_add_uint(vitc_tree, hf_st12_2_vitc_line_sel, tvb, 0, 0, dbb2);

        proto_item_set_generated(ti);

        ti = proto_tree_add_uint(vitc_tree, hf_st12_2_vitc_line_dup, tvb, 0, 0, dbb2);

        proto_item_set_generated(ti);

        ti = proto_tree_add_uint(vitc_tree, hf_st12_2_vitc_validity, tvb, 0, 0, dbb2);

        proto_item_set_generated(ti);

        ti = proto_tree_add_uint(vitc_tree, hf_st12_2_vitc_process, tvb, 0, 0, dbb2);

        proto_item_set_generated(ti);

    }

    proto_item_append_text(proto_tree_get_parent(st12_tree), ": %s", time_str);

    return tvb_captured_length(tvb);

}

void

proto_register_st12_2(void)

{

    static hf_register_info hf[] = {

        { &hf_st12_2_timecode,

          { "Time Code", "st12_2.timecode", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } },

        /* SMPTE ST 12-2:2014, Sec. 6.3, Table 6. */

        { &hf_st12_2_frame_units,

          { "Frame Units", "st12_2.time.frames.units", FT_UINT8, BASE_DEC, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_frame_tens,

          { "Frame Tens", "st12_2.time.frames.tens", FT_UINT8, BASE_DEC, NULL, 0x30, NULL,

            HFILL } },

        { &hf_st12_2_second_units,

          { "Second Units", "st12_2.time.seconds.units", FT_UINT8, BASE_DEC, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_second_tens,

          { "Second Tens", "st12_2.time.seconds.tens", FT_UINT8, BASE_DEC, NULL, 0x70, NULL,

            HFILL } },

        { &hf_st12_2_minute_units,

          { "Minute Units", "st12_2.time.minutes.units", FT_UINT8, BASE_DEC, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_minute_tens,

          { "Minute Tens", "st12_2.time.minutes.tens", FT_UINT8, BASE_DEC, NULL, 0x70, NULL,

            HFILL } },

        { &hf_st12_2_hour_units,

          { "Hour Units", "st12_2.time.hours.units", FT_UINT8, BASE_DEC, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_hour_tens,

          { "Hour Tens", "st12_2.time.hours.tens", FT_UINT8, BASE_DEC, NULL, 0x30, NULL, HFILL } },

        /*

         * SMPTE ST 12-2:2014, Sec. 6.3, Table 6;

         * SMPTE ST 12-1:2014, Table 3.

         */

        { &hf_st12_2_flag_bit_10,

          { "ST 12-1 Flag Bit 10 (Drop Frame in 30-frame systems)", "st12_2.flag.bit10",

            FT_BOOLEAN, 8, NULL, 0x40, NULL, HFILL } },

        { &hf_st12_2_flag_bit_11,

          { "ST 12-1 Flag Bit 11 (Color Frame in 30/25-frame systems)", "st12_2.flag.bit11",

            FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } },

        { &hf_st12_2_flag_bit_27,

          { "ST 12-1 Flag Bit 27", "st12_2.flag.bit27", FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } },

        { &hf_st12_2_flag_bit_43,

          { "ST 12-1 Flag Bit 43", "st12_2.flag.bit43", FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } },

        { &hf_st12_2_flag_bit_58,

          { "ST 12-1 Flag Bit 58", "st12_2.flag.bit58", FT_BOOLEAN, 8, NULL, 0x40, NULL, HFILL } },

        { &hf_st12_2_flag_bit_59,

          { "ST 12-1 Flag Bit 59", "st12_2.flag.bit59", FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } },

        /* SMPTE ST 12-2:2014, Sec. 6.3, Table 6; ST 12-1 Secs. 8.4-8.5. */

        { &hf_st12_2_binary_group_1,

          { "Binary Group 1", "st12_2.binary_group.1", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_binary_group_2,

          { "Binary Group 2", "st12_2.binary_group.2", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_binary_group_3,

          { "Binary Group 3", "st12_2.binary_group.3", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_binary_group_4,

          { "Binary Group 4", "st12_2.binary_group.4", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL,

            HFILL } },

        { &hf_st12_2_binary_group_5,

          { "Binary Group 5", "st12_2.binary_group.5", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL,

            HFILL } },