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/* packet-vp9.c
* Routines for VP9 dissection
* Copyright 2023, Noan Perrot <noan.perrot@gmail.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
* vp9-bitstream-specification-v0.6-20160331-draft - VP9 Bitstream & Decoding Process Specification
* draft-ietf-payload-vp9-16 - RTP Payload Format for VP9 Video
*/
#include "config.h"
/* Define the name for the logging domain (try to avoid collisions with existing domains) */
#define WS_LOG_DOMAIN "vp9"
/* Global header providing a minimum base set of required macros and APIs */
#include <wireshark.h>
#include <epan/packet.h> /* Required dissection API header */
#include <epan/expert.h> /* Include only as needed */
#include <epan/prefs.h> /* Include only as needed */
#define STRING_SIZE 50
#define VP9_1_BIT_MASK 0x80
#define VP9_2_BIT_MASK 0x40
#define VP9_3_BIT_MASK 0x20
#define VP9_4_BIT_MASK 0x10
#define VP9_5_BIT_MASK 0x08
#define VP9_6_BIT_MASK 0x04
#define VP9_7_BIT_MASK 0x02
#define VP9_8_BIT_MASK 0x01
#define VP9_2_BITS_MASK 0xC0
#define VP9_3_BITS_MASK 0xE0
#define VP9_7_BITS_MASK 0xFE
#define VP9_8_BITS_MASK 0xFF
#define VP9_16_BITS_MASK 0xFFFF
#define VP9_EXTENDED_PID 0x7FFF
static int proto_vp9;
static int hf_vp9_pld_i_bit;
static int hf_vp9_pld_p_bit;
static int hf_vp9_pld_l_bit;
static int hf_vp9_pld_f_bit;
static int hf_vp9_pld_b_bit;
static int hf_vp9_pld_e_bit;
static int hf_vp9_pld_v_bit;
static int hf_vp9_pld_z_bit;
static int hf_vp9_pld_u_bit;
static int hf_vp9_pld_m_bit;
static int hf_vp9_pld_d_bit;
static int hf_vp9_pld_n_bit;
static int hf_vp9_pld_y_bit;
static int hf_vp9_pld_g_bit;
static int hf_vp9_pld_pg_bits;
static int hf_vp9_pld_n_s_bits;
static int hf_vp9_pld_n_g_bits;
static int hf_vp9_pld_sid_bits;
static int hf_vp9_pld_pid_bits;
static int hf_vp9_pld_tid_bits;
static int hf_vp9_pld_width_bits;
static int hf_vp9_pld_height_bits;
static int hf_vp9_pld_n_s_numbers;
static int hf_vp9_pld_p_diff_bits;
static int hf_vp9_pld_tl0picidx_bits;
static int hf_vp9_pld_pg_extended_bits;
static int hf_vp9_pld_pid_extended_bits;
static int ett_vp9;
static int ett_vp9_descriptor;
static int *ett[] = {
&ett_vp9,
&ett_vp9_descriptor
};
static int
dissect_vp9(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree _U_, void *data _U_)
{
col_set_str(pinfo->cinfo, COL_PROTOCOL, "VP9");
proto_item *vp9_item = proto_tree_add_item(tree, proto_vp9, tvb, 0, -1, ENC_NA);
proto_tree *vp9_tree = proto_item_add_subtree(vp9_item, ett_vp9);
proto_item *vp9_descriptor_item;
proto_tree *vp9_descriptor_tree = proto_tree_add_subtree(vp9_tree, tvb, 0, 1, ett_vp9_descriptor, &vp9_descriptor_item, "Payload Descriptor");
int offset = 0;
/*
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|I|P|L|F|B|E|V|Z| (REQUIRED)
+-+-+-+-+-+-+-+-+
*/
uint8_t i = tvb_get_uint8(tvb, offset) & VP9_1_BIT_MASK;
uint8_t p = tvb_get_uint8(tvb, offset) & VP9_2_BIT_MASK;
uint8_t l = tvb_get_uint8(tvb, offset) & VP9_3_BIT_MASK;
uint8_t f = tvb_get_uint8(tvb, offset) & VP9_4_BIT_MASK;
uint8_t v = tvb_get_uint8(tvb, offset) & VP9_7_BIT_MASK;
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_i_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_p_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_l_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_f_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_b_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_e_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_v_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_z_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
/*
+-+-+-+-+-+-+-+-+
I: |M| PICTURE ID | (REQUIRED)
+-+-+-+-+-+-+-+-+
M: | EXTENDED PID | (RECOMMENDED)
+-+-+-+-+-+-+-+-+
*/
uint8_t m = tvb_get_uint8(tvb, offset) & VP9_1_BIT_MASK;
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_m_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
if (f)
{
// Flexible mode
if (m == i)
{
if (m)
{
// Extended PID
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_pid_extended_bits, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
else
{
// PID
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_pid_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
}
}
else
{
// Malformed packet
}
}
else
{
// Non-flexible mode
if (m == i)
{
if (m)
{
// Extended PID
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_pg_extended_bits, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
else
{
// PID
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_pg_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
}
}
else
{
// Malformed packet
}
}
/*
+-+-+-+-+-+-+-+-+
L: | TID |U| SID |D| (Conditionally RECOMMENDED)
+-+-+-+-+-+-+-+-+
*/
if (l)
{
// Layer indices present
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_tid_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_u_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_sid_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_d_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
if (f)
{
// 1 octet is present for the layer indices
proto_item_set_len(vp9_descriptor_item, 4);
}
else
{
// 2 octets are present for the layer indices
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_tl0picidx_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_item_set_len(vp9_descriptor_item, 5);
offset++;
}
}
/*
+-+-+-+-+-+-+-+-+ -\
P,F: | P_DIFF |N| (Conditionally REQUIRED) - up to 3 times
+-+-+-+-+-+-+-+-+ -/
*/
if (p && f)
{
uint8_t n = tvb_get_uint8(tvb, offset) & (VP9_1_BIT_MASK >> 7);
int idx = 0;
int max_p_diff = 3;
while (n && idx < max_p_diff)
{
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_p_diff_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_n_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_item_set_len(vp9_descriptor_item, 6);
offset++;
n = tvb_get_uint8(tvb, offset) & (VP9_1_BIT_MASK >> 7);
idx++;
if (n && idx == max_p_diff)
{
// Malformed packet
}
}
}
/*
+-+-+-+-+-+-+-+-+
V: | SS |
| .. |
+-+-+-+-+-+-+-+-+
*/
if (v)
{
/*
+-+-+-+-+-+-+-+-+
V: | N_S |Y|G|-|-|-|
+-+-+-+-+-+-+-+-+
*/
proto_item* n_s_numbers_field;
uint8_t n_s = (tvb_get_uint8(tvb, offset) & (VP9_3_BITS_MASK)) >> 5;
uint8_t y = tvb_get_uint8(tvb, offset) & (VP9_1_BIT_MASK >> 3);
uint8_t g = tvb_get_uint8(tvb, offset) & (VP9_1_BIT_MASK >> 4);
uint8_t number_of_spatial_layers = n_s + 1;
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_n_s_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
n_s_numbers_field = proto_tree_add_uint(vp9_descriptor_tree, hf_vp9_pld_n_s_numbers, tvb, offset, 1, number_of_spatial_layers);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_y_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_g_bit, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_item_set_generated(n_s_numbers_field);
offset++;
/*
+-+-+-+-+-+-+-+-+ -\
Y: | WIDTH | (OPTIONAL) .
+ + .
| | (OPTIONAL) .
+-+-+-+-+-+-+-+-+ . - N_S + 1 times
| HEIGHT | (OPTIONAL) .
+ + .
| | (OPTIONAL) .
+-+-+-+-+-+-+-+-+ -/
*/
uint8_t spatial_layer = 0;
while (spatial_layer < number_of_spatial_layers)
{
if (y)
{
// TODO: Add subtree for spatial layers
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_width_bits, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_height_bits, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
spatial_layer++;
}
/*
+-+-+-+-+-+-+-+-+
G: | N_G | (OPTIONAL)
+-+-+-+-+-+-+-+-+
*/
if (g)
{
/*
+-+-+-+-+-+-+-+-+ -\
N_G: | TID |U| R |-|-| (OPTIONAL) .
+-+-+-+-+-+-+-+-+ -\ . - N_G times
| P_DIFF | (OPTIONAL) . - R times .
+-+-+-+-+-+-+-+-+ -/ -/
*/
proto_tree_add_item(vp9_descriptor_tree, hf_vp9_pld_n_g_bits, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
// TODO: handle N_G
}
}
return tvb_captured_length(tvb);
}
void proto_register_vp9(void)
{
static hf_register_info hf[] = {
{&hf_vp9_pld_i_bit,
{"Picture ID present (I)", "vp9.pld.i",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_p_bit,
{"Inter-picture predicted frame (P)", "vp9.pld.p",
FT_BOOLEAN, 8,
NULL, VP9_2_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_l_bit,
{"Layer indices present (L)", "vp9.pld.l",
FT_BOOLEAN, 8,
NULL, VP9_3_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_f_bit,
{"Flexible mode (F)", "vp9.pld.f",
FT_BOOLEAN, 8,
NULL, VP9_4_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_b_bit,
{"Start of a frame (B)", "vp9.pld.b",
FT_BOOLEAN, 8,
NULL, VP9_5_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_e_bit,
{"End of a frame (E)", "vp9.pld.e",
FT_BOOLEAN, 8,
NULL, VP9_6_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_v_bit,
{"Scalability structure (SS) data present (V)", "vp9.pld.v",
FT_BOOLEAN, 8,
NULL, VP9_7_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_z_bit,
{"Not a reference frame for upper spatial layers (Z)", "vp9.pld.z",
FT_BOOLEAN, 8,
NULL, VP9_8_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_m_bit,
{"Extension flag (M)", "vp9.pld.m",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK,
NULL, HFILL}},
{&hf_vp9_pld_pid_bits,
{"Picture ID (PID)", "vp9.pld.pid",
FT_UINT8, BASE_DEC,
NULL, VP9_7_BITS_MASK >> 1,
NULL, HFILL}},
{&hf_vp9_pld_pid_extended_bits,
{"Picture ID (PID) Extended", "vp9.pld.pid_ext",
FT_UINT16, BASE_DEC,
NULL, VP9_EXTENDED_PID,
NULL, HFILL}},
{&hf_vp9_pld_pg_bits,
{"Picture Group Index (PG)", "vp9.pld.pg",
FT_UINT8, BASE_DEC,
NULL, VP9_7_BITS_MASK >> 1,
NULL, HFILL}},
{&hf_vp9_pld_pg_extended_bits,
{"Picture Group Index (PG) Extended", "vp9.pld.pg_ext",
FT_UINT16, BASE_DEC,
NULL, VP9_EXTENDED_PID,
NULL, HFILL}},
{&hf_vp9_pld_tid_bits,
{"Temporal layer ID", "vp9.pld.tid",
FT_UINT8, BASE_DEC,
NULL, VP9_3_BITS_MASK,
NULL, HFILL}},
{&hf_vp9_pld_u_bit,
{"Switching up point (U)", "vp9.pld.u",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK >> 3,
NULL, HFILL}},
{&hf_vp9_pld_sid_bits,
{"Spatial Layer ID", "vp9.pld.sid",
FT_UINT8, BASE_DEC,
NULL, VP9_3_BITS_MASK >> 4,
NULL, HFILL}},
{&hf_vp9_pld_d_bit,
{"Inter-layer dependency used (D)", "vp9.pld.d",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK >> 7,
NULL, HFILL}},
{&hf_vp9_pld_tl0picidx_bits,
{"Temporal layer zero index", "vp9.pld.tl0picidx",
FT_UINT8, BASE_DEC,
NULL, 0,
NULL, HFILL}},
{&hf_vp9_pld_p_diff_bits,
{"Reference index (P_DIFF)", "vp9.pld.p_diff",
FT_UINT8, BASE_DEC,
NULL, VP9_7_BITS_MASK,
NULL, HFILL}},
{&hf_vp9_pld_n_bit,
{"Additional reference index (N)", "vp9.pld.n",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK >> 7,
NULL, HFILL}},
{&hf_vp9_pld_n_s_bits,
{"Spatial layers minus 1 (N_S)", "vp9.pld.n_s",
FT_UINT8, BASE_DEC,
NULL, VP9_3_BITS_MASK,
NULL, HFILL}},
{&hf_vp9_pld_n_s_numbers,
{"Number of spatial layers", "vp9.pld.spatial_layers_number",
FT_UINT8, BASE_DEC,
NULL, 0,
NULL, HFILL}},
{&hf_vp9_pld_y_bit,
{"Spatial layer's frame resolution present (Y)", "vp9.pld.y",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK >> 3,
NULL, HFILL}},
{&hf_vp9_pld_g_bit,
{"PG description flag (G)", "vp9.pld.g",
FT_BOOLEAN, 8,
NULL, VP9_1_BIT_MASK >> 4,
NULL, HFILL}},
{&hf_vp9_pld_height_bits,
{"Height", "vp9.pld.height",
FT_UINT16, BASE_DEC,
NULL, 0,
NULL, HFILL}},
{&hf_vp9_pld_width_bits,
{"Width", "vp9.pld.width",
FT_UINT16, BASE_DEC,
NULL, 0,
NULL, HFILL}},
{&hf_vp9_pld_n_g_bits,
{"Number of pictures (N_G)", "vp9.pld.n_g",
FT_UINT8, BASE_DEC,
NULL, 0,
NULL, HFILL}}};
proto_vp9 = proto_register_protocol("VP9", "VP9", "vp9");
proto_register_field_array(proto_vp9, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void proto_reg_handoff_vp9(void)
{
static dissector_handle_t vp9_handle;
vp9_handle = register_dissector("vp9", dissect_vp9, proto_vp9);
dissector_add_string("rtp_dyn_payload_type", "vp9", vp9_handle);
dissector_add_uint_range_with_preference("rtp.pt", "", vp9_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
|
