Provided by: flvmeta_1.2.1-1build1_amd64 
NAME
flvmeta - manipulate or extract metadata in Adobe Flash Video files
SYNOPSIS
flvmeta INPUT_FILE
flvmeta INPUT_FILE OUTPUT_FILE
flvmeta -D|--dump [options] INPUT_FILE
flvmeta -F|--full-dump [options] INPUT_FILE
flvmeta -C|--check [options] INPUT_FILE
flvmeta -U|--update [options] INPUT_FILE [OUTPUT_FILE]
DESCRIPTION
flvmeta is a command-line utility aimed at manipulating Adobe(tm) Flash Video files (FLV), through sever‐
al commands, only one of which can be used for each invocation of the program.
It possesses the ability to compute and inject a variety of values in the onMetaData event tag, including
keyframe indices used by most video players to allow random-access seeking, notably for HTTP pseudo-
streamed files via a server-side module, by having the client send the file offset looked up for the
nearest desired keyframe.
Tools such as flvmeta must be used in the case the initial encoding process is unable to inject those
metadata.
It can also optionnally inject the onLastSecond event, used to signal the end of playback, for example to
revert the player software to a `stopped' state.
flvmeta also has the ability to dump metadata and full file information to standard output, in a variety
of textual output formats, including XML, YAML, and JSON.
Finally, the program can analyze FLV files to detect potential problems and errors, and generate a textu‐
al report as a raw format, as JSON, or as XML. It has the ability to detect more than a hundred prob‐
lems, going from harmless to potentially unplayable, using a few real world encountered issues.
flvmeta can operate on arbitrarily large files, and can handle FLV files using extended (32-bit) time‐
stamps. It can guess video frame dimensions for all known video codecs supported by the official FLV
specification.
Its memory usage remains minimal, as it uses a two-pass reading algorithm which permits the computation
of all necessary tags without loading anything more than the file’s tags headers in memory.
COMMANDS
Only one command can be specified for an invocation of flvmeta. The chosen command determines the mode
of execution of the program.
By default, if no command is specified, flvmeta will implicitly choose the command to use according to
the presence of INPUT_FILE and OUTPUT_FILE.
If only INPUT_FILE is present, the --dump command will be executed.
If both INPUT_FILE and OUTPUT_FILE are present, the --update command will be executed.
Here is a list of the supported commands:
-D, --dump
Dump a textual representation of the first onMetaData tag found in INPUT_FILE to standard output. The
default format is XML, unless specified otherwise.
It is also possible to specify another event via the --event option, such as onLastSecond.
-F, --full-dump
Dump a textual representation of the whole contents of INPUT_FILE to standard output. The default format
is XML, unless specified otherwise.
-C, --check
Print a report to standard output listing warnings and errors detected in INPUT_FILE, as well as poten‐
tial incompatibilities, and information about the codecs used in the file. The exit code will be set to
a non-zero value if there is at least one error in the file.
The output format can either be plain text, XML using the --xml option, or JSON using the --json option.
It can also be disabled altogether using the --quiet option if you are only interested in the exit sta‐
tus.
Messages are divided into four specific levels of increasing importance:
• info: informational messages that do not pertain to the file validity
• warning: messages that inform of oddities to the flv format but that might not hamper file reading or
playability, this is the default level
• error: messages that inform of errors that might render the file impossible to play or stream correctly
• fatal: messages that inform of errors that make further file reading impossible therefore ending pars‐
ing completely
The --level option allows flvmeta to limit the display of messages to a minimum level among those, for
example if the user is only interested in error messages and above.
Each message or message template presented to the user is identified by a specific code of the following
format:
[level][topic][id]
• level is an upper-case letter that can be either I, W, E, F according to the aforementioned message
levels
• topic is a two-digit integer representing the general topic of the message
• id is a unique three-digit identifier for the message, or message template if parameterized
Messages can be related to the following topics :
• 10 general flv file format
• 11 file header
• 12 previous tag size
• 20 tag format
• 30 tag types
• 40 timestamps
• 50 audio data
• 51 audio codecs
• 60 video data
• 61 video codecs
• 70 metadata
• 80 AMF data
• 81 keyframes
• 82 cue points
For example, represents a Warning in topic 51 with the id 050, which represents a warning message related
to audio codecs, in that case to signal that an audio tag has an unknown codec.
-U, --update
Update the given input file by inserting a computed onMetaData tag. If OUTPUT_FILE is specified, it will
be created or overwritten instead and the input file will not be modified. If the original file is to be
updated, a temporary file will be created in the default temp directory of the platform, and it will be
copied over the original file at the end of the operation. This is due to the fact that the output file
is written while the original file is being read due to the two-pass method.
The computed metadata contains among other data full keyframe information, in order to allow HTTP pseudo-
streaming and random-access seeking in the file.
By default, an onLastSecond tag will be inserted, unless the --no-last-second option is specified.
Normally overwritten by the update process, the existing metadata found in the input file can be pre‐
served by the --preserve option.
It is also possible to insert custom string values with the --add option, which can be specified multiple
times.
By default, the update operation is performed without output, unless the --verbose option is specified,
or the --print-metadata is used to print the newly written metadata to the standard output.
OPTIONS
DUMP
-d FORMAT, --dump-format=FORMAT
specify dump format where FORMAT is `xml' (default), `json', `raw', or `yaml'. Also applicable
for the --full-dump command.
-j, --json
equivalent to --dump-format=json
-r, --raw
equivalent to --dump-format=raw
-x, --xml
equivalent to --dump-format=xml
-y, --yaml
equivalent to --dump-format=yaml
-e EVENT, --event=EVENT
specify the event to dump instead of onMetaData, for example onLastSecond
CHECK
-l LEVEL, --level=LEVEL
print only messages where level is at least LEVEL. The levels are, by ascending importance, `in‐
fo', `warning' (default), `error', or `fatal'.
-q, --quiet
do not print messages, only return the status code
-x, --xml
generate an XML report instead of the default `compiler-friendly' text
-j, --json
generate a JSON report instead of the default `compiler-friendly' text
UPDATE
-m, --print-metadata
print metadata to stdout after update using the format specified by the --format option
-a NAME=VALUE, --add=NAME=VALUE
add a metadata string value to the output file. The name/value pair will be appended at the end
of the onMetaData tag.
-s, --no-lastsecond
do not create the onLastSecond tag
-p, --preserve
preserve input file existing onMetadata tags
-f, --fix
fix invalid tags from the input file
-i, --ignore
ignore invalid tags from the input file (the default behaviour is to stop the update process with
an error)
-t, --reset-timestamps
reset timestamps so OUTPUT_FILE starts at zero. This has been added because some FLV files are
produced by cutting bigger files, and the software doing the cutting does not resets the time‐
stamps as required by the standard, which can cause playback issues.
-k, –all-keyframes
index all keyframe tags, including duplicate timestamps
GENERAL
-v, --verbose
display informative messages
-V, --version
print version information and exit
-h, --help
display help on the program usage and exit
FORMATS
The various XML formats used by flvmeta are precisely described by the following XSD schemas:
• http://schemas.flvmeta.org/flv.xsd: describes the general organization of FLV files
• http://schemas.flvmeta.org/Amf0.xsd: describes an XML representation of the Adobe(TM) AMF0 serializa‐
tion format
• http://schemas.flvmeta.org/report.xsd: describes the XML output format of the --check --xml command
EXAMPLES
flvmeta example.flv
Prints the onMetadata tag contents of example.flv as XML output.
flvmeta example.flv out.flv
Creates a file named out.flv containing updated metadata and an onLastSecond tag from the exemple.flv
file.
flvmeta --check --xml --level=error example.flv
Checks the validity of the example.flv file and prints the error report to stdout in XML format, display‐
ing only errors and fatal errors.
flvmeta --full-dump --yaml example.flv
Prints the full contents of example.flv as YAML format to stdout.
flvmeta --update --no-last-second --show-metadata --json example.flv
Performs an in-place update of example.flv by inserting computed onMetadata without an onLastSecond tag,
and prints the newly inserted metadata on stdout as JSON.
EXIT STATUS
• 0 flvmeta exited without error
• 1 an error occurred when trying to open an input file
• 2 the input file was not recognized as an FLV file
• 3 an end-of-file condition was encountered unexpectedly
• 4 a memory allocation error occurred during the run of the program
• 5 an empty tag was encountered in an input file
• 6 an error occurred when trying to open an output file
• 7 an invalid tag was encountered in an input file
• 8 an error was encountered while writing an output file
• 9 the --check command reported an invalid file (one or more errors)
BUGS
flvmeta does not support encrypted FLV files yet.
AUTHOR
Marc Noirot <marc.noirot@gmail.com>
COPYRIGHT
Copyright 2007-2016 Marc Noirot
This is free software; see the source for copying conditions. There is NO warranty; not even for MER‐
CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
CONTACT
Please report bugs to <flvmeta-discussion@googlegroups.com>
flvmeta user manual January 2014 flvmeta(1)