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 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 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 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 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

CONTACT

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