vcap 无法打开 [udp @ 0x56378e8a76a0] 绑定失败：权限被拒绝
vcap failed to open[udp @ 0x56378e8a76a0] bind failed: Permission denied
我正在尝试使用带有 ipv6 地址的 opencv 的 VideoCapture 功能从我的 raspberry pi 流式传输到我的 debian 虚拟机，但是当我尝试时我在标题中遇到了错误。
我已经确认 ipv6 地址可以通过 netcat 和 mplayer 访问，具有以下内容：
Debian 主机：
netcat -l -6 -u 2222
raspberry pi:
/opt/vc/bin/raspivid -t 0 -w 300 -h 300 -hf -fps 20 -o - | nc -u (ipv6 地址) 2222
代码：
VideoCapture vcap;
const string videoStreamAddress = "udp://" + "(my Ipv6 address)" + ":2222";
vcap.open(videoStreamAddress);
编辑：我已经确认 vcap.open 可以使用 127.0.0.1，但问题是它仍然不适用于我的 ipv6 地址
以您指定的格式 <protocol>:// 使用的 IPv6 地址需要用方括号括起来（[ 和 ]）。这最初是在 RFC 2732, Format for Literal IPv6 Addresses in URL's and continued in RFC 3896:, Uniform Resource Identifier (URI): Generic Syntax:
中指定的
3.2.2. Host
The host subcomponent of authority is identified by an IP literal
encapsulated within square brackets, an IPv4 address in dotted-
decimal form, or a registered name. The host subcomponent is case-
insensitive. he presence of a host subcomponent within a URI does not
imply that the scheme requires access to the given host on the
Internet. In many cases, the host syntax is used only for the sake of
reusing the existing registration process created and deployed for
DNS, thus obtaining a globally unique name without the cost of
deploying another registry. However, such use comes with its own
costs: domain name ownership may change over time for reasons not
anticipated by the URI producer. In other cases, the data within the
host component identifies a registered name that has nothing to do
with an Internet host. We use the name "host" for the ABNF rule
because that is its most common purpose, not its only purpose.
host = IP-literal / IPv4address / reg-name
The syntax rule for host is ambiguous because it does not completely
distinguish between an IPv4address and a reg-name. In order to
disambiguate the syntax, we apply the "first-match-wins" algorithm: If
host matches the rule for IPv4address, then it should be considered an
IPv4 address literal and not a reg-name. Although host is
case-insensitive, producers and normalizers should use lowercase for
registered names and hexadecimal addresses for the sake of uniformity,
while only using uppercase letters for percent-encodings.
A host identified by an Internet Protocol literal address, version 6
[RFC3513] or later, is distinguished by enclosing the IP literal
within square brackets ("[" and "]"). This is the only place where
square bracket characters are allowed in the URI syntax. In
anticipation of future, as-yet-undefined IP literal address formats,
an implementation may use an optional version flag to indicate such a
format explicitly rather than rely on heuristic determination.
IP-literal = "[" ( IPv6address / IPvFuture ) "]"
IPvFuture = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )
The version flag does not indicate the IP version; rather, it
indicates future versions of the literal format. As such,
implementations must not provide the version flag for the existing
IPv4 and IPv6 literal address forms described below. If a URI
containing an IP-literal that starts with "v" (case-insensitive),
indicating that the version flag is present, is dereferenced by an
application that does not know the meaning of that version flag, then
the application should return an appropriate error for "address
mechanism not supported".
A host identified by an IPv6 literal address is represented inside the
square brackets without a preceding version flag. The ABNF provided
here is a translation of the text definition of an IPv6 literal
address provided in [RFC3513]. This syntax does not support IPv6
scoped addressing zone identifiers.
A 128-bit IPv6 address is divided into eight 16-bit pieces. Each piece
is represented numerically in case-insensitive hexadecimal, using one
to four hexadecimal digits (leading zeroes are permitted). The eight
encoded pieces are given most-significant first, separated by colon
characters. Optionally, the least-significant two pieces may instead
be represented in IPv4 address textual format. A sequence of one or
more consecutive zero-valued 16-bit pieces within the address may be
elided, omitting all their digits and leaving exactly two consecutive
colons in their place to mark the elision.
IPv6address = 6( h16 ":" ) ls32
/ "::" 5( h16 ":" ) ls32
/ [ h16 ] "::" 4( h16 ":" ) ls32
/ [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
/ [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
/ [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32
/ [ *4( h16 ":" ) h16 ] "::" ls32
/ [ *5( h16 ":" ) h16 ] "::" h16
/ [ *6( h16 ":" ) h16 ] "::"
ls32 = ( h16 ":" h16 ) / IPv4address
; least-significant 32 bits of address
h16 = 1*4HEXDIG
; 16 bits of address represented in hexadecimal
A host identified by an IPv4 literal address is represented in
dotted-decimal notation (a sequence of four decimal numbers in the
range 0 to 255, separated by "."), as described in [RFC1123] by
reference to [RFC0952]. Note that other forms of dotted notation may
be interpreted on some platforms, as described in Section 7.4, but
only the dotted-decimal form of four octets is allowed by this
grammar.
IPv4address = dec-octet "." dec-octet "." dec-octet "." dec-octet
dec-octet = DIGIT ; 0-9
/ %x31-39 DIGIT ; 10-99
/ "1" 2DIGIT ; 100-199
/ "2" %x30-34 DIGIT ; 200-249
/ "25" %x30-35 ; 250-255
A host identified by a registered name is a sequence of characters
usually intended for lookup within a locally defined host or service
name registry, though the URI's scheme-specific semantics may require
that a specific registry (or fixed name table) be used instead. The
most common name registry mechanism is the Domain Name System (DNS). A
registered name intended for lookup in the DNS uses the syntax defined
in Section 3.5 of [RFC1034] and Section 2.1 of [RFC1123]. Such a name
consists of a sequence of domain labels separated by ".", each domain
label starting and ending with an alphanumeric character and possibly
also containing "-" characters. The rightmost domain label of a fully
qualified domain name in DNS may be followed by a single "." and
should be if it is necessary to distinguish between the complete
domain name and some local domain.
reg-name = *( unreserved / pct-encoded / sub-delims )
If the URI scheme defines a default for host, then that default
applies when the host subcomponent is undefined or when the registered
name is empty (zero length). For example, the "file" URI scheme is
defined so that no authority, an empty host, and "localhost" all mean
the end-user's machine, whereas the "http" scheme considers a missing
authority or empty host invalid.
This specification does not mandate a particular registered name
lookup technology and therefore does not restrict the syntax of reg-
name beyond what is necessary for interoperability. Instead, it
delegates the issue of registered name syntax conformance to the
operating system of each application performing URI resolution, and
that operating system decides what it will allow for the purpose of
host identification. A URI resolution implementation might use DNS,
host tables, yellow pages, NetInfo, WINS, or any other system for
lookup of registered names. However, a globally scoped naming system,
such as DNS fully qualified domain names, is necessary for URIs
intended to have global scope. URI producers should use names that
conform to the DNS syntax, even when use of DNS is not immediately
apparent, and should limit these names to no more than 255 characters
in length.
The reg-name syntax allows percent-encoded octets in order to
represent non-ASCII registered names in a uniform way that is
independent of the underlying name resolution technology. Non-ASCII
characters must first be encoded according to UTF-8 [STD63], and then
each octet of the corresponding UTF-8 sequence must be percent-
encoded to be represented as URI characters. URI producing
applications must not use percent-encoding in host unless it is used
to represent a UTF-8 character sequence. When a non-ASCII registered
name represents an internationalized domain name intended for
resolution via the DNS, the name must be transformed to the IDNA
encoding [RFC3490] prior to name lookup. URI producers should provide
these registered names in the IDNA encoding, rather than a
percent-encoding, if they wish to maximize interoperability with
legacy URI resolvers.
我正在尝试使用带有 ipv6 地址的 opencv 的 VideoCapture 功能从我的 raspberry pi 流式传输到我的 debian 虚拟机，但是当我尝试时我在标题中遇到了错误。
我已经确认 ipv6 地址可以通过 netcat 和 mplayer 访问，具有以下内容：
Debian 主机：
netcat -l -6 -u 2222
raspberry pi:
/opt/vc/bin/raspivid -t 0 -w 300 -h 300 -hf -fps 20 -o - | nc -u (ipv6 地址) 2222
代码：
VideoCapture vcap;
const string videoStreamAddress = "udp://" + "(my Ipv6 address)" + ":2222";
vcap.open(videoStreamAddress);
编辑：我已经确认 vcap.open 可以使用 127.0.0.1，但问题是它仍然不适用于我的 ipv6 地址
以您指定的格式 <protocol>:// 使用的 IPv6 地址需要用方括号括起来（[ 和 ]）。这最初是在 RFC 2732, Format for Literal IPv6 Addresses in URL's and continued in RFC 3896:, Uniform Resource Identifier (URI): Generic Syntax:
3.2.2. Host
The host subcomponent of authority is identified by an IP literal encapsulated within square brackets, an IPv4 address in dotted- decimal form, or a registered name. The host subcomponent is case- insensitive. he presence of a host subcomponent within a URI does not imply that the scheme requires access to the given host on the Internet. In many cases, the host syntax is used only for the sake of reusing the existing registration process created and deployed for DNS, thus obtaining a globally unique name without the cost of deploying another registry. However, such use comes with its own costs: domain name ownership may change over time for reasons not anticipated by the URI producer. In other cases, the data within the host component identifies a registered name that has nothing to do with an Internet host. We use the name "host" for the ABNF rule because that is its most common purpose, not its only purpose.
host = IP-literal / IPv4address / reg-nameThe syntax rule for host is ambiguous because it does not completely distinguish between an IPv4address and a reg-name. In order to disambiguate the syntax, we apply the "first-match-wins" algorithm: If host matches the rule for IPv4address, then it should be considered an IPv4 address literal and not a reg-name. Although host is case-insensitive, producers and normalizers should use lowercase for registered names and hexadecimal addresses for the sake of uniformity, while only using uppercase letters for percent-encodings.
A host identified by an Internet Protocol literal address, version 6 [RFC3513] or later, is distinguished by enclosing the IP literal within square brackets ("[" and "]"). This is the only place where square bracket characters are allowed in the URI syntax. In anticipation of future, as-yet-undefined IP literal address formats, an implementation may use an optional version flag to indicate such a format explicitly rather than rely on heuristic determination.
IP-literal = "[" ( IPv6address / IPvFuture ) "]" IPvFuture = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )The version flag does not indicate the IP version; rather, it indicates future versions of the literal format. As such, implementations must not provide the version flag for the existing IPv4 and IPv6 literal address forms described below. If a URI containing an IP-literal that starts with "v" (case-insensitive), indicating that the version flag is present, is dereferenced by an application that does not know the meaning of that version flag, then the application should return an appropriate error for "address mechanism not supported".
A host identified by an IPv6 literal address is represented inside the square brackets without a preceding version flag. The ABNF provided here is a translation of the text definition of an IPv6 literal address provided in [RFC3513]. This syntax does not support IPv6 scoped addressing zone identifiers.
A 128-bit IPv6 address is divided into eight 16-bit pieces. Each piece is represented numerically in case-insensitive hexadecimal, using one to four hexadecimal digits (leading zeroes are permitted). The eight encoded pieces are given most-significant first, separated by colon characters. Optionally, the least-significant two pieces may instead be represented in IPv4 address textual format. A sequence of one or more consecutive zero-valued 16-bit pieces within the address may be elided, omitting all their digits and leaving exactly two consecutive colons in their place to mark the elision.
IPv6address = 6( h16 ":" ) ls32 / "::" 5( h16 ":" ) ls32 / [ h16 ] "::" 4( h16 ":" ) ls32 / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32 / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32 / [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32 / [ *4( h16 ":" ) h16 ] "::" ls32 / [ *5( h16 ":" ) h16 ] "::" h16 / [ *6( h16 ":" ) h16 ] "::" ls32 = ( h16 ":" h16 ) / IPv4address ; least-significant 32 bits of address h16 = 1*4HEXDIG ; 16 bits of address represented in hexadecimalA host identified by an IPv4 literal address is represented in dotted-decimal notation (a sequence of four decimal numbers in the range 0 to 255, separated by "."), as described in [RFC1123] by reference to [RFC0952]. Note that other forms of dotted notation may be interpreted on some platforms, as described in Section 7.4, but only the dotted-decimal form of four octets is allowed by this grammar.
IPv4address = dec-octet "." dec-octet "." dec-octet "." dec-octet dec-octet = DIGIT ; 0-9 / %x31-39 DIGIT ; 10-99 / "1" 2DIGIT ; 100-199 / "2" %x30-34 DIGIT ; 200-249 / "25" %x30-35 ; 250-255A host identified by a registered name is a sequence of characters usually intended for lookup within a locally defined host or service name registry, though the URI's scheme-specific semantics may require that a specific registry (or fixed name table) be used instead. The most common name registry mechanism is the Domain Name System (DNS). A registered name intended for lookup in the DNS uses the syntax defined in Section 3.5 of [RFC1034] and Section 2.1 of [RFC1123]. Such a name consists of a sequence of domain labels separated by ".", each domain label starting and ending with an alphanumeric character and possibly also containing "-" characters. The rightmost domain label of a fully qualified domain name in DNS may be followed by a single "." and should be if it is necessary to distinguish between the complete domain name and some local domain.
reg-name = *( unreserved / pct-encoded / sub-delims )If the URI scheme defines a default for host, then that default applies when the host subcomponent is undefined or when the registered name is empty (zero length). For example, the "file" URI scheme is defined so that no authority, an empty host, and "localhost" all mean the end-user's machine, whereas the "http" scheme considers a missing authority or empty host invalid.
This specification does not mandate a particular registered name lookup technology and therefore does not restrict the syntax of reg- name beyond what is necessary for interoperability. Instead, it delegates the issue of registered name syntax conformance to the operating system of each application performing URI resolution, and that operating system decides what it will allow for the purpose of host identification. A URI resolution implementation might use DNS, host tables, yellow pages, NetInfo, WINS, or any other system for lookup of registered names. However, a globally scoped naming system, such as DNS fully qualified domain names, is necessary for URIs intended to have global scope. URI producers should use names that conform to the DNS syntax, even when use of DNS is not immediately apparent, and should limit these names to no more than 255 characters in length.
The reg-name syntax allows percent-encoded octets in order to represent non-ASCII registered names in a uniform way that is independent of the underlying name resolution technology. Non-ASCII characters must first be encoded according to UTF-8 [STD63], and then each octet of the corresponding UTF-8 sequence must be percent- encoded to be represented as URI characters. URI producing applications must not use percent-encoding in host unless it is used to represent a UTF-8 character sequence. When a non-ASCII registered name represents an internationalized domain name intended for resolution via the DNS, the name must be transformed to the IDNA encoding [RFC3490] prior to name lookup. URI producers should provide these registered names in the IDNA encoding, rather than a percent-encoding, if they wish to maximize interoperability with legacy URI resolvers.