Ubuntu Manpage: flvmeta - manipulate or extract metadata in Adobe Flash Video files

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
several 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
textual report as a raw format, as JSON, or as XML. It has the ability to detect more than a hundred
problems, 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)
timestamps. 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 implicitely 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
potential 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
status.

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
parsing 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
preserved 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,
              'info', '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
              timestamps 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
         serialization 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,
       displaying 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 occured 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 occured during the run of the program
       • 5 an empty tag was encountered in an input file
       • 6 an error occured 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 2007-2013 Marc Noirot

       This  is  free  software;  see  the  source  for  copying conditions.  There is NO warranty; not even for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

CONTACT

       Please report bugs to <flvmeta-discussion@googlegroups.com>

flvmeta user manual                                August 2013                                        flvmeta(1)