Third-party tools are available to create and modify FLV files, but some of the tools create files that do not comply with the FLV standard. Common problems include bad timestamps in the FLV file, invalid onMetaData messages, bad message headers, and corrupted audio and video. The FLVCheck tool can be used to analyze FLV files before they are deployed on Flash Media Server. In addition, the tool can also add or update metadata to reflect file duration correctly. The tool verifies that metadata is readable, specifies an accurate duration, and checks that the FLV file is seekable by Flash Media Server. The tool supports unicode filenames.

Flash Media Server supports playback and recording of H.264-encoded video and HE-AAC-encoded audio within an MPEG-4–based container format. A subset of the MPEG-4 standards are supported. All MP4 files and Adobe F4V files are part of the supported subset.

For MPEG-4–based container formats, use the FLVCheck tool to verify that the server can play back your files.

The FLVCheck tool is a command line program; the executable is named flvcheck.

1. Open your operating system’s command prompt and change directories to RootInstall/tools.

2. Use the following syntax to run the FLVCheck tool:

   flvcheck [-option] <file ...>

   For example, to check two files:

   flvcheck -f abc.flv ../test/123.flv 

   The following table describes the command line options available.

   Option	Description
   -f [ --file ] file ...	Specifies the path to the video file(s) being checked. Relative paths may be used. (Avoid using the “\\xd3 character; try the “/” character instead.)
   -v [--verbose]	Sets the verbose flag.
   -V [ --version ]	Prints version information.
   -n [ --nobanner ]	Turns off header.
   -h [ --help ]	Provides a description of options and an example.
   -d [ --duration ]	Specifies the margin of error, in seconds, that FLVCheck reports. (The default is 2 seconds.) When validating metadata, the absolute difference between metadata_duration and actual_duration is calculated and compared against the margin specified in this command. If the margin is exceeded, the server logs a warning that the metadata duration is incorrect. If the margin has not been exceeded, nothing will be logged. To get the exact duration, specify -d 0.
   -q [ --quiet ]	Specifies that only the status code, not the text output, be returned. The --help option overrides this option.
   -w [ --warnings]	Display warnings.
   -W [--warnings_as_errors]	Treat warnings as errors.
   -s [ --fixvideostall ]	Fix a stall in video playback (FLV only).
   -u [ --usage ]	Displays an example and information about command-line parameters.
   -m [ --fixmeta ]	(FLV files only) If a metadata tag is corrupted, creates a new copy of the original FLV file in the same directory as the original, with corrected metadata. (If the file contains no errors, a backup file is not created.) Only the Duration and Can Seek To End metadata fields are corrected.

3. If the FLVCheck tool finds no errors in the FLV file, the status code returned is 0. If there are one or more errors, a positive number indicating the total number of invalid files found is returned. If a return code of -1 is returned, an invalid command-line parameter was specified.

   Errors and warnings are logged in a log file (stdout).

4. (FLV files only) If an error is returned from an FLV file due to a metadata error, you can use the tool to try to correct the problem. Try the following:

   1. Use the -m option to try to fix the metadata in the file:

      flvcheck -m <file> [-quiet] [-help]

   2. Use the -d option to change the duration field margin of error. The duration field in the metadata may be inaccurate by a few seconds. For example, flvcheck -f abc.flv -d 5 would allow the metadata duration to be inaccurate +/- 5 seconds.

      Other types of errors cannot be fixed using the FLVCheck tool. MP4/F4V files cannot be fixed using the FLVCheck tool.

If an error is found, the error is logged to the stdout file in the following format: Date, Time, ErrorNumber, ErrorMessage, and FileName. The possible error numbers, types of errors, and messages are as follows.

Generally, warnings are informative and are not fatal errors; Flash Media Server will ignore the error that caused the warning and continue to load and play back the video or audio file, but you may experience problems with playback. Warnings are logged to the stdout file in the following format: Date, Time, Warning Number, Warning Message, and File Name.