More dissecting of H.263 according to RFC 4629.
svn path=/trunk/; revision=20983
This commit is contained in:
Anders Broman
parent
262de6677a
commit
fd3a3c5d52
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@ -103,6 +103,12 @@ static int hf_h263P_pbit = -1;
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static int hf_h263P_vbit = -1;
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static int hf_h263P_plen = -1;
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static int hf_h263P_pebit = -1;
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static int hf_h263P_tid = -1;
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static int hf_h263P_trun = -1;
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static int hf_h263P_s = -1;
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static int hf_h263P_extra_hdr = -1;
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static int hf_h263P_PSC = -1;
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static int hf_h263P_TR = -1;
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/* Source format types */
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#define SRCFORMAT_FORB 0 /* forbidden */
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@ -132,6 +138,13 @@ static const true_false_string picture_coding_type_flg = {
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"INTRA (I-picture)"
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};
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static const value_string picture_coding_type_vals[] =
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{
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{ 0, "I-Frame" },
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{ 1, "P-frame" },
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{ 0, NULL },
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};
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static const true_false_string PB_frames_mode_flg = {
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"PB-frame",
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"Normal I- or P-picture"
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@ -144,6 +157,7 @@ static gint ett_h263_payload = -1;
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/* H.263-1998 fields defining a sub tree */
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static gint ett_h263P = -1;
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static gint ett_h263P_payload = -1;
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static gint ett_h263P_data = -1;
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static void
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dissect_h263( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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@ -301,7 +315,9 @@ static void
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dissect_h263P( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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{
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proto_item *ti = NULL;
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proto_tree *h263P_tree = NULL;
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proto_item *data_item = NULL;
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proto_tree *h263P_tree = NULL;
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proto_tree *h263P_data_tree = NULL;
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unsigned int offset = 0;
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guint16 data16, plen;
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guint8 octet;
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@ -327,25 +343,130 @@ dissect_h263P( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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proto_tree_add_item( h263P_tree, hf_h263P_pebit, tvb, offset, 2, FALSE );
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offset = offset +2;
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/*
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* V: 1 bit
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*
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* Indicates the presence of an 8-bit field containing information
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* for Video Redundancy Coding (VRC), which follows immediately after
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* the initial 16 bits of the payload header, if present. For syntax
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* and semantics of that 8-bit VRC field, see Section 5.2.
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*/
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if ((data16&0x0200)==0x0200){
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/* V bit = 1
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* The format of the VRC header extension is as follows:
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*
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* 0 1 2 3 4 5 6 7
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* +-+-+-+-+-+-+-+-+
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* | TID | Trun |S|
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* +-+-+-+-+-+-+-+-+
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*
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* TID: 3 bits
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*
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* Thread ID. Up to 7 threads are allowed. Each frame of H.263+ VRC
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* data will use as reference information only sync frames or frames
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* within the same thread. By convention, thread 0 is expected to be
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* the "canonical" thread, which is the thread from which the sync frame
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* should ideally be used. In the case of corruption or loss of the
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* thread 0 representation, a representation of the sync frame with a
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* higher thread number can be used by the decoder. Lower thread
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* numbers are expected to contain representations of the sync frames
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* equal to or better than higher thread numbers in the absence of data
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* corruption or loss. See [Vredun] for a detailed discussion of VRC.
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*
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* Trun: 4 bits
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*
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* Monotonically increasing (modulo 16) 4-bit number counting the packet
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* number within each thread.
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*
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* S: 1 bit
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*
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* A bit that indicates that the packet content is for a sync frame.
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* :
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*/
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proto_tree_add_item( h263P_tree, hf_h263P_tid, tvb, offset, 1, FALSE );
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proto_tree_add_item( h263P_tree, hf_h263P_trun, tvb, offset, 1, FALSE );
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proto_tree_add_item( h263P_tree, hf_h263P_s, tvb, offset, 1, FALSE );
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offset++;
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}
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plen = (data16 & 0x01f8) >> 3;
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if (plen != 0){
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/* Length, in bytes, of the extra picture header. */
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proto_tree_add_item( h263P_tree, hf_h263P_extra_hdr, tvb, offset, plen, FALSE );
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offset = offset + plen;
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}
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if ((data16&0x0400)!=0){
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/ P bit = 1 /
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/* P bit = 1 */
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data_item = proto_tree_add_item( h263P_tree, hf_h263P_payload, tvb, offset, -1, FALSE );
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h263P_data_tree = proto_item_add_subtree( data_item, ett_h263P_data );
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octet = tvb_get_guint8(tvb,offset);
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if((octet&0xfc)==0x80){
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/ PSC /
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/* Check for PSC, PSC is a word of 22 bits. Its value is 0000 0000 0000 0000' 1000 00xx xxxx xxxx.
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* Here without the first two 0 bytes of the PSC
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*/
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if ( check_col( pinfo->cinfo, COL_INFO) )
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col_append_str( pinfo->cinfo, COL_INFO, "(PSC) ");
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proto_tree_add_item( h263P_data_tree, hf_h263P_PSC, tvb, offset, 2, FALSE );
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proto_tree_add_item( h263P_data_tree, hf_h263P_TR, tvb, offset, 2, FALSE );
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/*
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* Bit 1: Always "1", in order to avoid start code emulation.
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* Bit 2: Always "0", for distinction with Recommendation H.261.
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*/
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offset = offset + 2;
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/* Bit 3: Split screen indicator, "0" off, "1" on. */
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proto_tree_add_item( h263P_data_tree, hf_h263_split_screen_indicator, tvb, offset, 1, FALSE );
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/* Bit 4: Document camera indicator, */
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proto_tree_add_item( h263P_data_tree, hf_h263_document_camera_indicator, tvb, offset, 1, FALSE );
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/* Bit 5: Full Picture Freeze Release, "0" off, "1" on. */
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proto_tree_add_item( h263P_data_tree, hf_h263_full_picture_freeze_release, tvb, offset, 1, FALSE );
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/* Bits 6-8: Source Format, "000" forbidden, "001" sub-QCIF, "010" QCIF, "011" CIF,
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* "100" 4CIF, "101" 16CIF, "110" reserved, "111" extended PTYPE.
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*/
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proto_tree_add_item( h263P_data_tree, hf_h263_source_format, tvb, offset, 1, TRUE );
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octet = tvb_get_guint8(tvb,offset);
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if (( octet & 0x1c) != 0x1c){
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/* Not extended PTYPE */
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/* Bit 9: Picture Coding Type, "0" INTRA (I-picture), "1" INTER (P-picture). */
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proto_tree_add_item( h263P_data_tree, hf_h263_payload_picture_coding_type, tvb, offset, 1, FALSE );
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if ( check_col( pinfo->cinfo, COL_INFO) )
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col_append_fstr(pinfo->cinfo, COL_INFO, val_to_str((octet & 0x02)>>1, picture_coding_type_vals, "Unknown (%u)"));
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/* Bit 10: Optional Unrestricted Motion Vector mode (see Annex D), "0" off, "1" on. */
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proto_tree_add_item( h263P_data_tree, hf_h263_opt_unres_motion_vector_mode, tvb, offset, 1, FALSE );
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offset++;
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/* Bit 11: Optional Syntax-based Arithmetic Coding mode (see Annex E), "0" off, "1" on.*/
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proto_tree_add_item( h263P_data_tree, hf_h263_syntax_based_arithmetic_coding_mode, tvb, offset, 1, FALSE );
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/* Bit 12: Optional Advanced Prediction mode (see Annex F), "0" off, "1" on.*/
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proto_tree_add_item( h263P_data_tree, hf_h263_optional_advanced_prediction_mode, tvb, offset, 1, FALSE );
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/* Bit 13: Optional PB-frames mode (see Annex G), "0" normal I- or P-picture, "1" PB-frame.*/
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proto_tree_add_item( h263P_data_tree, hf_h263_PB_frames_mode, tvb, offset, 1, FALSE );
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}
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return;
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}else{
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/*
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if ( check_col( pinfo->cinfo, COL_INFO) )
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col_append_str( pinfo->cinfo, COL_INFO, "(GBSC) ");
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*/
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}
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}
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*/
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offset = offset + plen;
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proto_tree_add_item( h263P_tree, hf_h263P_payload, tvb, offset, -1, FALSE );
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}
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}
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/*
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TODO: Add these?
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End Of Sequence (EOS) (22 bits)
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A codeword of 22 bits. Its value is 0000 0000 0000 0000 1 11111.
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Group of Block Start Code (GBSC) (17 bits)
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A word of 17 bits. Its value is 0000 0000 0000 0000 1.
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End Of Sub-Bitstream code (EOSBS) (23 bits)
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The EOSBS code is a codeword of 23 bits. Its value is 0000 0000 0000 0000 1 11110 0.
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Slice Start Code (SSC) (17 bits)
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A word of 17 bits. Its value is 0000 0000 0000 0000 1.
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*/
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static void dissect_h263_data( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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{
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guint offset = 0;
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@ -394,6 +515,9 @@ static void dissect_h263_data( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tr
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/* Not extended PTYPE */
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/* Bit 9: Picture Coding Type, "0" INTRA (I-picture), "1" INTER (P-picture). */
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proto_tree_add_item( h263_payload_tree, hf_h263_payload_picture_coding_type, tvb, offset, 1, FALSE );
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if ( check_col( pinfo->cinfo, COL_INFO) )
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col_append_fstr(pinfo->cinfo, COL_INFO, val_to_str((octet & 0x02)>>1, picture_coding_type_vals, "Unknown (%u)"));
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/* Bit 10: Optional Unrestricted Motion Vector mode (see Annex D), "0" off, "1" on. */
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proto_tree_add_item( h263_payload_tree, hf_h263_opt_unres_motion_vector_mode, tvb, offset, 1, FALSE );
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offset++;
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@ -962,12 +1086,87 @@ proto_register_h263P(void)
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}
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},
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{
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&hf_h263P_tid,
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{
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"Thread ID",
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"h263P.tid",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0xe0,
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"Thread ID", HFILL
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}
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},
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{
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&hf_h263P_trun,
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{
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"Trun",
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"h263P.trun",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x1e,
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"Monotonically increasing (modulo 16) 4-bit number counting the packet number within each thread", HFILL
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}
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},
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{
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&hf_h263P_s,
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{
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"S",
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"h263P.s",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x01,
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"Indicates that the packet content is for a sync frame", HFILL
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}
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},
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{
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&hf_h263P_extra_hdr,
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{
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"Extra picture header",
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"h263P.extra_hdr",
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FT_BYTES,
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BASE_NONE,
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NULL,
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0x0,
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"Extra picture header", HFILL
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}
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},
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{
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&hf_h263P_PSC,
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{
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"H.263 PSC",
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"h263P.PSC",
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FT_UINT16,
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BASE_HEX,
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NULL,
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0xfc00,
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"Picture Start Code(PSC)", HFILL
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}
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},
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{
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&hf_h263P_TR,
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{
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"H.263 Temporal Reference",
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"h263P.tr",
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FT_UINT16,
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BASE_HEX,
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NULL,
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0x03fc,
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"Temporal Reference, TR", HFILL
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}
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},
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};
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static gint *ett[] =
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{
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&ett_h263P,
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&ett_h263P_payload,
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&ett_h263P_data,
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};
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