Fix/repair flv files (make flv files seekable,playable,inject metadata,fix duration)

Sometimes when you download/capture flash video .FLV files with a Flash stream recorder, it turns out that they are corrupted (flv video plays too fast, flv video is not seekable, flv video is not playble, flv video stops after a few seconds).

How to fix FLV files: Re-download the video

The common way to fix this problem is to re-download the video using the same Flash stream recorder or another one that handles FLV files better.

How to fix FLV files: Remux FLV (h.264) file into MP4 file
You can remux an FLV file into an MP4 file quickly without any transcoding.

Get freeware FLV Extract and freeware mp4box.

Using FLV Extract, drag the recorded/downloaded .FLV file to the FLV Extract window. It will demux into video and audio files, ending in .264 and .aac

Then, use mp4box to remux those files into an MP4:

mp4box.exe -add "filename.264:fps=23.976" -add "filename.aac" "filename_output.mp4"

Where "filename" is the name of the .264 and .aac files. The output .mp4 will play properly and have the correct time length.

Instead of mp4box you can use freeware GUI utility YAMB.

Please note that mp4box and YAMB may give different results

How to fix FLV files: Add (inject) metadata with Replay Media Catcher 4

Replay Media Catcher 4 allows to fix time and duration of flash videos files. This allows to fix audio/video sync problems of flash video files and make FLV files seekable.

How to fix time and duration with Fix FLV tool of RMC 4:

1. Click Tools -> Fix FLV and select the file to be fixed.
   Or, if the file is still in Replay Media Catcher's main list, right-click on it and select Fix FLV.
2. Hit the "Fix duration" button.
3. After fixing duration (note that RMC fixes duration automatically after recording) expand the File Contents section
   
   
   
4. Set timestamp to 15 and hit the "Fix Time" button.

If the resulting file is still fast or slow then the time stamp can be adjusted further. But, 15 usually does the trick. Be sure to click the Fix Time button, or your changes will not be applied.

How to fix FLV files: Add (inject) metadata with FLVMDI

FLV MetaData Injector (FLVMDI) is a Win32 console (command line) application that can add 'onMetaData' AMF data to FLV files. (There's also a GUI frontend FLVMDIGUI). FLVMDI optionally saves an XML version of the injected data, and can add an additional string data or save the onMetaData data to an XML file. FLVMDI has some unique functionality, but it's not as vital now because flashcom 1.5.2+ and Flash Video Exporter 1.2+ adds the required metadata. (Unfortunately there's still a gotcha with Sorenson Squeeze 4, also see Sorenson Squeeze (4.1) FLV Metadata upate...).

FLV Meta Data Injector inserts proper meta data into FLV files, such as video size, length, last keyframe and more. You can select the options that are needed like "Include keyframes" and "Inject OnLastSecond Event":
- "Include Keyframes" inserts periodic keyframes into the video to assist with non-seekable FLV videos. Some FLV files are not seekable, so you can't fast forward or rewind them.
- "Inject OnLastSecond" inserts one final second after the video, to help remedy situations where FLV videos end too early.

FLV MetaData Injector can batch process a folder of FLV video files. It is not recommended to work with more than a dozen of files at a time, because the software will probably crash.

FLV MetaData Injector is compatible with Windows XP, Windows Server 2003/2008, Windows Vista, and Windows 7.



FLVMDI and FLVMDIGUI are free to use.


We will use FLV MetaData Injector (FLVMDI) and FLVMDIGUI to fix/repair flv files by injecting metadata.

1. Download FLVMDI and FLVMDIGUI archives and extract FLVMDI.exe and FLVMDIGUI.exe into the same folder (like C:\FLVMDI\).
   
2. Run FLVMDIGUI.exe
3. Select the FLV video that you want to fix/repair.
   
   You can also batch repair FLV video files by selecting the folder where all the videos reside.
4. Choose the desired additional options
5. Hit the "RUN FLVMDI" button.
6. If "Output progress" checkbox is checked, you will be shown the complete progress of the metadata injection.
7. When the process of repairing/fixing FLV file(s) is completer, try to play your video(s).

How to fix FLV files: More options

Originally Posted by blimey

The flv fixer in GetFLV is just the same as (is actually lifted from) the freeware FLVMDI. So, it has all the same limitations as FLVMDI. It is mostly helpful for setting duration data, but it won't necessarily always start at 0:00.

The fix tool in Replay Media Catcher 4 (Jaksta) is actually quite powerful, although I wish it had a few more options: like the ability to set the start hex value of the first time stamp, or the ability to do a range of timestamps without manual selection. But, it is very good for setting duration data and setting the timing interval values.

Some other tools to try are FLVTool2, and RichFLV. RichFLV requires adobe air, and often crashes while reading a file. But when it does work it does a good job.

How to fix FLV files: Build VBR Time Map with AviDemux

Avidemux is a freeware video editor for Linux, Mac OS and Windows

To fix FLV files with AviDemux:

1. Run AviDemux and open FLV file with it
2. Select "Audio" -> "Build VBR Time Map"
3. Change the Format (container) to MP4 if needed
4. Save the video under a new name (If you save it under the same name your original video will be lost!!!)