/* packet-h263.c * * Routines for ITU-T Recommendation H.263 dissection * * Copyright 2003 Niklas Ogren * Seven Levels Consultants AB * * Copyright 2008 Richard van der Hoff, MX Telecom * * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * Copied structure from packet-h261.c * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include "packet-h263.h" void proto_register_h263_data(void); static int proto_h263_data = -1; /* Fields for the data section */ static int hf_h263_psc = -1; static int hf_h263_gbsc = -1; static int hf_h263_TR =-1; static int hf_h263_split_screen_indicator = -1; static int hf_h263_document_camera_indicator = -1; static int hf_h263_full_picture_freeze_release = -1; static int hf_h263_source_format = -1; static int hf_h263_payload_picture_coding_type = -1; static int hf_h263_opt_unres_motion_vector_mode = -1; static int hf_h263_syntax_based_arithmetic_coding_mode = -1; static int hf_h263_optional_advanced_prediction_mode = -1; static int hf_h263_PB_frames_mode = -1; static int hf_h263_data = -1; static int hf_h263_GN = -1; static int hf_h263_UFEP = -1; static int hf_h263_opptype = -1; static int hf_h263_pquant = -1; static int hf_h263_cpm = -1; static int hf_h263_psbi = -1; static int hf_h263_picture_type_code = -1; static int hf_h263_ext_source_format = -1; static int hf_h263_custom_pcf = -1; static int hf_h263_pei = -1; static int hf_h263_psupp = -1; static int hf_h263_trb = -1; static int hf_h263_not_dissected = -1; /* H.263 fields defining a sub tree */ static gint ett_h263_payload = -1; static gint ett_h263_optype = -1; /* Source format types */ #define H263_SRCFORMAT_FORB 0 /* forbidden */ #define H263_SRCFORMAT_SQCIF 1 #define H263_SRCFORMAT_QCIF 2 #define H263_SRCFORMAT_CIF 3 #define H263_SRCFORMAT_4CIF 4 #define H263_SRCFORMAT_16CIF 5 #define H263_PLUSPTYPE 7 const value_string h263_srcformat_vals[] = { { H263_SRCFORMAT_FORB, "forbidden" }, { H263_SRCFORMAT_SQCIF, "sub-QCIF 128x96" }, { H263_SRCFORMAT_QCIF, "QCIF 176x144" }, { H263_SRCFORMAT_CIF, "CIF 352x288" }, { H263_SRCFORMAT_4CIF, "4CIF 704x576" }, { H263_SRCFORMAT_16CIF, "16CIF 1408x1152" }, { 6, "Reserved",}, { H263_PLUSPTYPE, "extended PTYPE" }, { 0, NULL }, }; /* * If UFEP is "001", then the following bits are present in PLUSPTYPE: * Bits 1-3 Source Format, "000" reserved, "001" sub-QCIF, "010" QCIF, "011" CIF, * "100" 4CIF, "101" 16CIF, "110" custom source format, "111" reserved; */ static const value_string ext_srcformat_vals[] = { { 0, "reserved" }, { H263_SRCFORMAT_SQCIF, "sub-QCIF 128x96" }, { H263_SRCFORMAT_QCIF, "QCIF 176x144" }, { H263_SRCFORMAT_CIF, "CIF 352x288" }, { H263_SRCFORMAT_4CIF, "4CIF 704x576" }, { H263_SRCFORMAT_16CIF, "16CIF 1408x1152" }, { 6, "Custom source format",}, { 7, "Reserved" }, { 0, NULL }, }; static const value_string h263_ufep_vals[] = { { 0, "Only MPPTYPE included" }, { 1, "All extended PTYPE fields are included" }, { 0, NULL }, }; static const true_false_string picture_coding_type_flg = { "INTER (P-picture)", "INTRA (I-picture)" }; static const value_string picture_coding_type_vals[] = { { 0, "I-Frame" }, { 1, "P-frame" }, { 0, NULL }, }; static const true_false_string PB_frames_mode_flg = { "PB-frame", "Normal I- or P-picture" }; static const true_false_string custom_pcf_flg = { "Custom PCF", "CIF PCF" }; /* Bits 1-3 Picture Type Code:*/ static const value_string picture_type_code_vals[] = { { 0, "I-picture (INTRA)" }, { 1, "P-picture (INTER)" }, { 2, "Improved PB-frame (see Annex M)" }, { 3, "B-picture (see Annex O)" }, { 4, "EI-picture (see Annex O)" }, { 5, "EP-picture (see Annex O)" }, { 6, "Reserved" }, { 7, "Reserved" }, { 0, NULL }, }; /* * 5.3 Macroblock layer static int dissect_h263_macroblock_layer( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gint offset) { } */ int dissect_h263_group_of_blocks_layer( tvbuff_t *tvb, proto_tree *tree, gint offset, gboolean is_rfc4626) { unsigned int offset_in_bits = offset << 3; if(is_rfc4626){ /* GBSC 1xxx xxxx */ proto_tree_add_bits_item(tree, hf_h263_gbsc, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; }else{ /* Group of Block Start Code (GBSC) (17 bits) * A word of 17 bits. Its value is 0000 0000 0000 0000 1. */ proto_tree_add_bits_item(tree, hf_h263_gbsc, tvb, offset_in_bits, 17, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +17; } /* * Group Number (GN) (5 bits) */ proto_tree_add_bits_item(tree, hf_h263_GN, tvb, offset_in_bits, 5, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +5; /* 5.2.4 GOB Sub-Bitstream Indicator (GSBI) (2 bits) * A fixed length codeword of 2 bits that is only present if CPM is "1" in the picture header. */ /* * 5.2.5 GOB Frame ID (GFID) (2 bits) */ /* * 5.2.6 Quantizer Information (GQUANT) (5 bits) */ /* * 5.3 Macroblock layer */ return offset_in_bits>>3; } /* * Length is used for the "Extra header" otherwise set to -1. */ int dissect_h263_picture_layer( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gint offset, gint length _U_, gboolean is_rfc4626) { proto_tree *h263_opptype_tree = NULL; proto_item *opptype_item = NULL; unsigned int offset_in_bits = offset << 3; unsigned int saved_bit_offset; guint64 source_format; guint64 ufep; guint64 picture_coding_type; guint64 PB_frames_mode = 0; guint64 custom_pcf = 0; guint64 picture_type_code =0; guint64 cpm; guint64 pei; if(is_rfc4626){ /* PC 1000 00xx */ proto_tree_add_bits_item(tree, hf_h263_psc, tvb, offset_in_bits, 6, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +6; }else{ /* Check for PSC, PSC is a word of 22 bits. * Its value is 0000 0000 0000 0000' 1000 00xx xxxx xxxx. */ proto_tree_add_bits_item(tree, hf_h263_psc, tvb, offset_in_bits, 22, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +22; } proto_tree_add_bits_item(tree, hf_h263_TR, tvb, offset_in_bits, 8, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +8; /* * Bit 1: Always "1", in order to avoid start code emulation. * Bit 2: Always "0", for distinction with Recommendation H.261. */ offset_in_bits = offset_in_bits +2; /* Bit 3: Split screen indicator, "0" off, "1" on. */ proto_tree_add_bits_item( tree, hf_h263_split_screen_indicator, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bit 4: Document camera indicator, */ proto_tree_add_bits_item( tree, hf_h263_document_camera_indicator, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bit 5: Full Picture Freeze Release, "0" off, "1" on. */ proto_tree_add_bits_item( tree, hf_h263_full_picture_freeze_release, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bits 6-8: Source Format, "000" forbidden, "001" sub-QCIF, "010" QCIF, "011" CIF, * "100" 4CIF, "101" 16CIF, "110" reserved, "111" extended PTYPE. */ proto_tree_add_bits_ret_val( tree, hf_h263_source_format, tvb, offset_in_bits, 3 ,&source_format, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +3; if (source_format != H263_PLUSPTYPE){ /* Not extended PTYPE */ /* Bit 9: Picture Coding Type, "0" INTRA (I-picture), "1" INTER (P-picture). */ proto_tree_add_bits_ret_val( tree, hf_h263_payload_picture_coding_type, tvb, offset_in_bits, 1, &picture_coding_type, ENC_BIG_ENDIAN); col_append_str(pinfo->cinfo, COL_INFO, val_to_str((guint32)picture_coding_type, picture_coding_type_vals, "Unknown (%u)")); offset_in_bits++; /* Bit 10: Optional Unrestricted Motion Vector mode (see Annex D), "0" off, "1" on. */ proto_tree_add_bits_item( tree, hf_h263_opt_unres_motion_vector_mode, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bit 11: Optional Syntax-based Arithmetic Coding mode (see Annex E), "0" off, "1" on.*/ proto_tree_add_bits_item( tree, hf_h263_syntax_based_arithmetic_coding_mode, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bit 12: Optional Advanced Prediction mode (see Annex F), "0" off, "1" on.*/ proto_tree_add_bits_item( tree, hf_h263_optional_advanced_prediction_mode, tvb, offset_in_bits, 1, ENC_BIG_ENDIAN); offset_in_bits++; /* Bit 13: Optional PB-frames mode (see Annex G), "0" normal I- or P-picture, "1" PB-frame.*/ proto_tree_add_bits_ret_val( tree, hf_h263_PB_frames_mode, tvb, offset_in_bits, 1, &PB_frames_mode, ENC_BIG_ENDIAN); offset_in_bits++; }else{ /* Extended PTYPE * Update Full Extended PTYPE (UFEP) (3 bits) */ /* .... ..xx x... .... */ proto_tree_add_bits_ret_val( tree, hf_h263_UFEP, tvb, offset_in_bits, 3, &ufep, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +3; if(ufep==1){ /* The Optional Part of PLUSPTYPE (OPPTYPE) (18 bits) */ /* .xxx xxxx xxxx xxxx xxx. .... */ opptype_item = proto_tree_add_bits_item( tree, hf_h263_opptype, tvb, offset_in_bits, 18, ENC_BIG_ENDIAN); h263_opptype_tree = proto_item_add_subtree( opptype_item, ett_h263_optype ); /* * If UFEP is "001", then the following bits are present in PLUSPTYPE: * Bits 1-3 Source Format, "000" reserved, "001" sub-QCIF, "010" QCIF, "011" CIF, * "100" 4CIF, "101" 16CIF, "110" custom source format, "111" reserved; */ proto_tree_add_bits_item( h263_opptype_tree, hf_h263_ext_source_format, tvb, offset_in_bits, 3, ENC_BIG_ENDIAN); offset_in_bits+=3; /* * Bit 4 Optional Custom PCF, "0" CIF PCF, "1" custom PCF; */ proto_tree_add_bits_ret_val( h263_opptype_tree, hf_h263_custom_pcf, tvb, offset_in_bits, 1, &custom_pcf, ENC_BIG_ENDIAN); offset_in_bits++; saved_bit_offset=offset_in_bits; /* * Bit 5 Optional Unrestricted Motion Vector (UMV) mode (see Annex D), "0" off, "1" on; */ offset_in_bits++; /* * Bit 6 Optional Syntax-based Arithmetic Coding (SAC) mode (see Annex E), "0" off, "1" on; */ offset_in_bits++; /* * Bit 7 Optional Advanced Prediction (AP) mode (see Annex F), "0" off, "1" on; */ offset_in_bits++; /* * Bit 8 Optional Advanced INTRA Coding (AIC) mode (see Annex I), "0" off, "1" on; */ offset_in_bits++; /* * Bit 9 Optional Deblocking Filter (DF) mode (see Annex J), "0" off, "1" on; */ offset_in_bits++; /* * Bit 10 Optional Slice Structured (SS) mode (see Annex K), "0" off, "1" on; */ offset_in_bits++; /* * Bit 11 Optional Reference Picture Selection (RPS) mode (see Annex N), "0" off, "1" on; */ offset_in_bits++; /* * Bit 12 Optional Independent Segment Decoding (ISD) mode (see Annex R), "0" off,"1" on; */ offset_in_bits++; /* * Bit 13 Optional Alternative INTER VLC (AIV) mode (see Annex S), "0" off, "1" on; */ offset_in_bits++; /* * Bit 14 Optional Modified Quantization (MQ) mode (see Annex T), "0" off, "1" on; */ offset_in_bits++; /* * Bit 15 Equal to "1" to prevent start code emulation; */ offset_in_bits++; /* * Bit 16 Reserved, shall be equal to "0"; */ offset_in_bits++; /* * Bit 17 Reserved, shall be equal to "0"; */ offset_in_bits++; /* * Bit 18 Reserved, shall be equal to "0". */ offset_in_bits++; proto_tree_add_bits_item( h263_opptype_tree, hf_h263_not_dissected, tvb, saved_bit_offset, offset_in_bits-saved_bit_offset, ENC_BIG_ENDIAN); } /* * 5.1.4.3 The mandatory part of PLUSPTYPE when PLUSPTYPE present (MPPTYPE) (9 bits) * Regardless of the value of UFEP, the following 9 bits are also present in PLUSPTYPE: * - Bits 1-3 Picture Type Code: * "000" I-picture (INTRA); * "001" P-picture (INTER); * "010" Improved PB-frame (see Annex M); * "011" B-picture (see Annex O); * "100" EI-picture (see Annex O); * "101" EP-picture (see Annex O); * "110" Reserved; * "111" Reserved; */ proto_tree_add_bits_ret_val( tree, hf_h263_picture_type_code, tvb, offset_in_bits, 3, &picture_type_code, ENC_BIG_ENDIAN); offset_in_bits+=3; saved_bit_offset=offset_in_bits; /* * Bit 4 Optional Reference Picture Resampling (RPR) mode (see Annex P), "0" off, "1" on; */ offset_in_bits++; /* * Bit 5 Optional Reduced-Resolution Update (RRU) mode (see Annex Q), "0" off, "1" on; */ offset_in_bits++; /* * Bit 6 Rounding Type (RTYPE) (see 6.1.2); */ offset_in_bits++; /* * Bit 7 Reserved, shall be equal to "0"; */ offset_in_bits++; /* * Bit 8 Reserved, shall be equal to "0"; */ offset_in_bits++; /* * Bit 9 Equal to "1" to prevent start code emulation. */ offset_in_bits++; proto_tree_add_bits_item( tree, hf_h263_not_dissected, tvb, saved_bit_offset, offset_in_bits-saved_bit_offset, ENC_BIG_ENDIAN); /* The picture header location of CPM (1 bit) and PSBI (2 bits) * the picture header depends on whether or not PLUSPTYPE is present * (see 5.1.20 and 5.1.21). If PLUSPTYPE is present, then CPM follows * immediately after PLUSPTYPE in the picture header. */ proto_tree_add_bits_ret_val( tree, hf_h263_cpm, tvb, offset_in_bits, 1, &cpm, ENC_BIG_ENDIAN); offset_in_bits++; /* 5.1.21 Picture Sub-Bitstream Indicator (PSBI) (2 bits) * only present if Continuous Presence Multipoint and Video * Multiplex mode is indicated by CPM. */ if(cpm==1){ proto_tree_add_bits_item( tree, hf_h263_psbi, tvb, offset_in_bits, 2, ENC_BIG_ENDIAN); offset_in_bits+=2; } return offset_in_bits>>3; /* TODO Add the rest of the fields */ /* 5.1.5 Custom Picture Format (CPFMT) (23 bits) * present only if the use of a custom picture format is * signalled in PLUSPTYPE and UFEP is '001'. When present, CPFMT consists of: * Bits 1-4 Pixel Aspect Ratio Code: A 4-bit index to the PAR value in Table 5. For * extended PAR, the exact pixel aspect ratio shall be specified in EPAR * (see 5.1.6); * Bits 5-13 Picture Width Indication: Range [0, ... , 511]; Number of pixels per * line = (PWI + 1) * 4; * Bit 14 Equal to "1" to prevent start code emulation; * Bits 15-23 Picture Height Indication: Range [1, ... , 288]; Number of lines = PHI * 4. */ /* 5.1.6 Extended Pixel Aspect Ratio (EPAR) (16 bits) * A fixed length codeword of 16 bits that is present only if CPFMT is present and extended PAR is * indicated therein. When present, EPAR consists of: * Bits 1-8 PAR Width: "0" is forbidden. The natural binary representation of the PAR * width; * Bits 9-16 PAR Height: "0" is forbidden. The natural binary representation of the PAR * height. */ /* 5.1.7 Custom Picture Clock Frequency Code (CPCFC) (8 bits) * A fixed length codeword of 8 bits that is present only if PLUSPTYPE is present and UFEP is 001 * and a custom picture clock frequency is signalled in PLUSPTYPE. When present, CPCFC consists of: * Bit 1 Clock Conversion Code: "0" indicates a clock conversion factor of 1000 and * "1" indicates 1001; * Bits 2-8 Clock Divisor: "0" is forbidden. The natural binary representation of the value * of the clock divisor. */ /* 5.1.8 Extended Temporal Reference (ETR) (2 bits) * A fixed length codeword of 2 bits which is present only if a custom picture clock frequency is in * use (regardless of the value of UFEP). It is the two MSBs of the 10-bit number defined in 5.1.2. */ /* 5.1.9 Unlimited Unrestricted Motion Vectors Indicator (UUI) (Variable length) * A variable length codeword of 1 or 2 bits that is present only if the optional Unrestricted Motion * Vector mode is indicated in PLUSPTYPE and UFEP is 001. When UUI is present it indicates the * effective limitation of the range of the motion vectors being used. * UUI = "1" The motion vector range is limited according to Tables D.1 and D.2. * UUI = "01" The motion vector range is not limited except by the picture size. */ /* * 5.1.10 Slice Structured Submode bits (SSS) (2 bits) * A fixed length codeword of 2 bits which is present only if the optional Slice Structured mode * (see Annex K) is indicated in PLUSPTYPE and UFEP is 001. If the Slice Structured mode is in use * but UFEP is not 001, the last values sent for SSS shall remain in effect. * - Bit 1 Rectangular Slices, "0" indicates free-running slices, "1" indicates rectangular * slices; * - Bit 2 Arbitrary Slice Ordering, "0" indicates sequential order, "1" indicates arbitrary * order. * 5.1.11 Enhancement Layer Number (ELNUM) (4 bits) * A fixed length codeword of 4 bits which is present only if the optional Temporal, SNR, and Spatial * Scalability mode is in use (regardless of the value of UFEP). The particular enhancement layer is * identified by an enhancement layer number, ELNUM. Picture correspondence between layers is * achieved via the temporal reference. Picture size is either indicated within each enhancement layer * using the existing source format fields or is inferred by the relationship to the reference layer. The * first enhancement layer above the base layer is designated as Enhancement Layer Number 2, and * the base layer has number 1. * 5.1.12 Reference Layer Number (RLNUM) (4 bits) * A fixed length codeword of 4 bits which is present only if the optional Temporal, SNR, and Spatial * Scalability mode is in use (see Annex O) and UFEP is 001. The layer number for the pictures used * as reference anchors is identified by a Reference Layer Number (RLNUM). Time correspondence * between layers is achieved via the temporal reference. * Note that for B-pictures in an enhancement layer having temporally surrounding EI- or EP-pictures * which are present in the same enhancement layer, RLNUM shall be equal to ELNUM * (see Annex O). * 5.1.13 Reference Picture Selection Mode Flags (RPSMF) (3 bits) * A fixed length codeword of 3 bits that is present only if the Reference Picture Selection mode is in * use and UFEP is 001. When present, RPSMF indicates which type of back-channel messages are * needed by the encoder. If the Reference Picture Selection mode is in use but RPSMF is not present, * the last value of RPSMF that was sent shall remain in effect. * - 100: neither ACK nor NACK signals needed; * - 101: need ACK signals to be returned; * - 110: need NACK signals to be returned; * - 111: need both ACK and NACK signals to be returned; * - 000-011: Reserved. * 5.1.14 Temporal Reference for Prediction Indication (TRPI) (1 bit) * A fixed length codeword of 1 bit that is present only if the optional Reference Picture Selection * mode is in use (regardless of the value of UFEP). When present, TRPI indicates the presence of the * following TRP field: * - 0: TRP field is not present; * - 1: TRP field is present. * TRPI shall be 0 whenever the picture header indicates an I- or EI-picture. * 5.1.15 Temporal Reference for Prediction (TRP) (10 bits) * When present (as indicated in TRPI), TRP indicates the Temporal Reference which is used for * prediction of the encoding, except for in the case of B-pictures. For B-pictures, the picture having * the temporal reference TRP is used for the prediction in the forward direction. (Prediction in the * reverse-temporal direction always uses the immediately temporally subsequent picture.) TRP is a * ten-bit number. If a custom picture clock frequency was not in use for the reference picture, the two * MSBs of TRP are zero and the LSBs contain the eight-bit TR found in the picture header of the * reference picture. If a custom picture clock frequency was in use for the reference picture, TRP is a * ten-bit number consisting of the concatenation of ETR and TR from the reference picture header. * When TRP is not present, the most recent temporally previous anchor picture shall be used for * prediction, as when not in the Reference Picture Selection mode. TRP is valid until the next PSC, * GSC, or SSC. * 5.1.16 Back-Channel message Indication (BCI) (Variable length) * A variable length field of one or two bits that is present only if the optional Reference Picture * Selection mode is in use. When set to "1", this signals the presence of the following optional video * Back-Channel Message (BCM) field. "01" indicates the absence or the end of the video backchannel * message field. Combinations of BCM and BCI may not be present, and may be repeated * when present. BCI shall be set to "01" if the videomux submode of the optional Reference Picture * Selection mode is not in use. * 5.1.17 Back-Channel Message (BCM) (Variable length) * The Back-Channel message with syntax as specified in N.4.2, which is present only if the preceding * BCI field is present and is set to "1". * 5.1.18 Reference Picture Resampling Parameters (RPRP) (Variable length) * A variable length field that is present only if the optional Reference Picture Resampling mode bit is * set in PLUSPTYPE. This field carries the parameters of the Reference Picture Resampling mode * (see Annex P). Note that the Reference Picture Resampling mode can also be invoked implicitly by * the occurrence of a picture header for an INTER coded picture having a picture size which differs * from that of the previous encoded picture, in which case the RPRP field is not present and the * Reference Picture Resampling mode bit is not set. */ } /* 5.1.19 Quantizer Information (PQUANT) (5 bits) */ proto_tree_add_bits_item( tree, hf_h263_pquant, tvb, offset_in_bits, 5, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +5; if (source_format != H263_PLUSPTYPE){ proto_tree_add_bits_ret_val( tree, hf_h263_cpm, tvb, offset_in_bits, 1, &cpm, ENC_BIG_ENDIAN); offset_in_bits++; /* 5.1.21 Picture Sub-Bitstream Indicator (PSBI) (2 bits) * only present if Continuous Presence Multipoint and Video * Multiplex mode is indicated by CPM. */ if(cpm==1){ proto_tree_add_bits_item( tree, hf_h263_psbi, tvb, offset_in_bits, 2, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +2; } } /* 5.1.22 Temporal Reference for B-pictures in PB-frames (TRB) (3/5 bits) * TRB is present if PTYPE or PLUSPTYPE indicates "PB-frame" or "Improved PB-frame" * It is 3 bits long for standard CIF picture clock frequency and is * extended to 5 bits when a custom picture clock frequency is in use. */ if((PB_frames_mode == 1)||(picture_type_code == 2 )){ if(custom_pcf == 0){ proto_tree_add_bits_item( tree, hf_h263_trb, tvb, offset_in_bits, 3, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +3; }else{ proto_tree_add_bits_item( tree, hf_h263_trb, tvb, offset_in_bits, 5, ENC_BIG_ENDIAN); offset_in_bits = offset_in_bits +5; } } /* 5.1.23 Quantization information for B-pictures in PB-frames (DBQUANT) (2 bits) * DBQUANT is present if PTYPE or PLUSPTYPE indicates "PB-frame" or "Improved PB-frame" */ if((PB_frames_mode == 1)||(picture_type_code == 2 )){ offset_in_bits = offset_in_bits +2; } /* 5.1.24 Extra Insertion Information (PEI) (1 bit) * A bit which when set to "1" signals the presence of the following optional data field. */ proto_tree_add_bits_ret_val( tree, hf_h263_pei, tvb, offset_in_bits, 1, &pei, ENC_BIG_ENDIAN); offset_in_bits++; while(pei==1) { /*5.1.25 Supplemental Enhancement Information (PSUPP) (0/8/16 ... bits) * If PEI is set to "1", then 9 bits follow consisting of 8 bits of data (PSUPP) and then another PEI bit * to indicate if a further 9 bits follow and so on. Encoders shall use PSUPP as specified in Annex L. */ proto_tree_add_bits_item( tree, hf_h263_psupp, tvb, offset_in_bits, 8, ENC_BIG_ENDIAN); offset_in_bits+=8; proto_tree_add_bits_ret_val( tree, hf_h263_pei, tvb, offset_in_bits, 1, &pei, ENC_BIG_ENDIAN); offset_in_bits++; } /* For the first GOB in each picture (with number 0), no GOB header shall be transmitted. * For all other GOBs, the GOB header may be empty, depending on the encoder strategy. */ /* * 5.3 Macroblock layer * dissect_h263_macroblock_layer( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gint offset) */ return offset_in_bits>>3; } /* 5.1.1 Picture Start Code (PSC) (22 bits) PSC is a word of 22 bits. Its value is 0000 0000 0000 0000 1 00000. All picture start codes shall be byte aligned. ( 1000 00xx) End Of Sequence (EOS) (22 bits) A codeword of 22 bits. Its value is 0000 0000 0000 0000 1 11111. ( 1111 11xx ) Group of Block Start Code (GBSC) (17 bits) A word of 17 bits. Its value is 0000 0000 0000 0000 1. ( 1xxx xxxx ) End Of Sub-Bitstream code (EOSBS) (23 bits) The EOSBS code is a codeword of 23 bits. Its value is 0000 0000 0000 0000 1 11110 0. ( 1111 100x ) Slice Start Code (SSC) (17 bits) A word of 17 bits. Its value is 0000 0000 0000 0000 1. ( 1xxx xxxx ) */ static int dissect_h263_data( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* dissector_data _U_ ) { guint offset = 0; proto_item *h263_payload_item = NULL; proto_tree *h263_payload_tree = NULL; guint32 data; guint8 startcode; int length; col_append_str( pinfo->cinfo, COL_INFO, "H263 payload "); h263_payload_item = proto_tree_add_item( tree, proto_h263_data, tvb, offset, -1, ENC_NA ); h263_payload_tree = proto_item_add_subtree( h263_payload_item, ett_h263_payload ); length = tvb_reported_length_remaining(tvb,0); if(length<4){ if( tree ) proto_tree_add_item( h263_payload_tree, hf_h263_data, tvb, offset, -1, ENC_NA ); return tvb_captured_length(tvb); } /* Check for PSC, PSC is a word of 22 bits. Its value is 0000 0000 0000 0000' 1000 00xx xxxx xxxx. */ data = tvb_get_ntohl(tvb, offset); if (( data & 0xffff8000) == 0x00008000 ) { /* Start Code found * * Startc code holds bit 17 -23 of the codeword */ startcode = tvb_get_guint8(tvb,offset+2)&0xfe; if (startcode & 0x80){ switch(startcode){ case 0xf8: /* End Of Sub-Bitstream code (EOSBS) * ( 1111 100. ) */ break; case 0x80: case 0x82: /* Picture Start Code (PSC) * ( 1000 00x.) */ col_append_str( pinfo->cinfo, COL_INFO, "(PSC) "); offset = dissect_h263_picture_layer( tvb, pinfo, h263_payload_tree, offset, -1, ENC_NA); break; case 0xfc: case 0xfe: /* End Of Sequence (EOS) * ( 1111 11x. ) */ default: /* Group of Block Start Code (GBSC) or * Slice Start Code (SSC) */ col_append_str( pinfo->cinfo, COL_INFO, "(GBSC) "); offset = dissect_h263_group_of_blocks_layer( tvb, h263_payload_tree, offset,FALSE); break; } }else{ /* Error */ } } if( tree ) proto_tree_add_item( h263_payload_tree, hf_h263_data, tvb, offset, -1, ENC_NA ); return tvb_captured_length(tvb); } void proto_register_h263_data(void) { static hf_register_info hf[] = { { &hf_h263_psc, { "H.263 Picture start Code", "h263.psc", FT_UINT32, BASE_HEX, NULL, 0x0, "Picture start Code, PSC", HFILL } }, { &hf_h263_gbsc, { "H.263 Group of Block Start Code", "h263.gbsc", FT_UINT32, BASE_HEX, NULL, 0x0, "Group of Block Start Code", HFILL } }, { &hf_h263_TR, { "H.263 Temporal Reference", "h263.tr2", FT_UINT32, BASE_DEC, NULL, 0x0, "Temporal Reference, TR", HFILL } }, { &hf_h263_trb, { "Temporal Reference for B frames", "h263.trb", FT_UINT8, BASE_DEC, NULL, 0x0, "Temporal Reference for the B frame as defined by H.263", HFILL } }, { &hf_h263_split_screen_indicator, { "H.263 Split screen indicator", "h263.split_screen_indicator", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Split screen indicator", HFILL } }, { &hf_h263_document_camera_indicator, { "H.263 Document camera indicator", "h263.document_camera_indicator", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Document camera indicator", HFILL } }, { &hf_h263_full_picture_freeze_release, { "H.263 Full Picture Freeze Release", "h263.split_screen_indicator", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Full Picture Freeze Release", HFILL } }, { &hf_h263_source_format, { "H.263 Source Format", "h263.source_format", FT_UINT8, BASE_HEX, VALS(h263_srcformat_vals), 0x0, "Source Format", HFILL } }, { &hf_h263_ext_source_format, { "H.263 Source Format", "h263.ext_source_format", FT_UINT8, BASE_HEX, VALS(ext_srcformat_vals), 0x0, "Source Format", HFILL } }, { &hf_h263_UFEP, { "H.263 Update Full Extended PTYPE", "h263.ufep", FT_UINT16, BASE_DEC, VALS(h263_ufep_vals), 0x0, "Update Full Extended PTYPE", HFILL } }, { &hf_h263_opptype, { "H.263 Optional Part of PLUSPTYPE", "h263.opptype", FT_UINT24, BASE_DEC, NULL, 0x0, "Optional Part of PLUSPTYPE", HFILL } }, { &hf_h263_payload_picture_coding_type, { "H.263 Picture Coding Type", "h263.picture_coding_type", FT_BOOLEAN, BASE_NONE, TFS(&picture_coding_type_flg), 0x0, "Picture Coding Type", HFILL } }, { &hf_h263_opt_unres_motion_vector_mode, { "H.263 Optional Unrestricted Motion Vector mode", "h263.opt_unres_motion_vector_mode", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Optional Unrestricted Motion Vector mode", HFILL } }, { &hf_h263_syntax_based_arithmetic_coding_mode, { "H.263 Optional Syntax-based Arithmetic Coding mode", "h263.syntax_based_arithmetic_coding_mode", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Optional Syntax-based Arithmetic Coding mode", HFILL } }, { &hf_h263_optional_advanced_prediction_mode, { "H.263 Optional Advanced Prediction mode", "h263.optional_advanced_prediction_mode", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Optional Advanced Prediction mode", HFILL } }, { &hf_h263_PB_frames_mode, { "H.263 Optional PB-frames mode", "h263.PB_frames_mode", FT_BOOLEAN, BASE_NONE, TFS(&PB_frames_mode_flg), 0x0, "Optional PB-frames mode", HFILL } }, { &hf_h263_GN, { "H.263 Group Number", "h263.gn", FT_UINT32, BASE_DEC, NULL, 0x0, "Group Number, GN", HFILL } }, { &hf_h263_pquant, { "H.263 Quantizer Information (PQUANT)", "h263.pquant", FT_UINT32, BASE_DEC, NULL, 0x0, "Quantizer Information (PQUANT)", HFILL } }, { &hf_h263_cpm, { "H.263 Continuous Presence Multipoint and Video Multiplex (CPM)", "h263.cpm", FT_BOOLEAN, BASE_NONE, TFS(&tfs_on_off), 0x0, "Continuous Presence Multipoint and Video Multiplex (CPM)", HFILL } }, { &hf_h263_psbi, { "H.263 Picture Sub-Bitstream Indicator (PSBI)", "h263.psbi", FT_UINT32, BASE_DEC, NULL, 0x0, "Picture Sub-Bitstream Indicator (PSBI)", HFILL } }, { &hf_h263_picture_type_code, { "H.263 Picture Type Code", "h263.psi", FT_UINT32, BASE_DEC, VALS(picture_type_code_vals), 0x0, "Picture Type Code", HFILL } }, { &hf_h263_custom_pcf, { "H.263 Custom PCF", "h263.custom_pcf", FT_BOOLEAN, BASE_NONE, TFS(&custom_pcf_flg), 0x0, "Custom PCF", HFILL } }, { &hf_h263_pei, { "H.263 Extra Insertion Information (PEI)", "h263.pei", FT_BOOLEAN, BASE_NONE, NULL, 0x0, "Extra Insertion Information (PEI)", HFILL } }, { &hf_h263_psupp, { "H.263 Supplemental Enhancement Information (PSUPP)", "h263.psupp", FT_UINT32, BASE_DEC, NULL, 0x0, "Supplemental Enhancement Information (PSUPP)", HFILL } }, { &hf_h263_data, { "H.263 stream", "h263.stream", FT_BYTES, BASE_NONE, NULL, 0x0, "The H.263 stream including its Picture, GOB or Macro block start code.", HFILL } }, { &hf_h263_not_dissected, { "H.263 Bits currently not dissected", "h263.not_dis", FT_UINT32, BASE_DEC, NULL, 0x0, "These bits are not dissected(yet), displayed for clarity", HFILL } }, }; static gint *ett[] = { &ett_h263_payload, &ett_h263_optype, }; proto_register_subtree_array(ett, array_length(ett)); proto_h263_data = proto_register_protocol("ITU-T Recommendation H.263", "H.263", "h263"); proto_register_field_array(proto_h263_data, hf, array_length(hf)); register_dissector("h263data", dissect_h263_data, proto_h263_data); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 8 * tab-width: 8 * indent-tabs-mode: t * End: * * vi: set shiftwidth=8 tabstop=8 noexpandtab: * :indentSize=8:tabSize=8:noTabs=false: */