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