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wireshark/epan/dissectors/packet-h263.c

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/* packet-h263.c
*
* Routines for ITU-T Recommendation H.263 dissection
*
* Copyright 2003 Niklas Ogren <niklas.ogren@7l.se>
* Seven Levels Consultants AB
*
* Copyright 2008 Richard van der Hoff, MX Telecom
* <richardv@mxtelecom.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Copied structure from packet-h261.c
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#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:
*/
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