Repairing FLV files by remuxing them with freeware FLV Extract and mp4box

[blimey]

The index of the saved .flv file can be off. This may cause playability issues with some .flv players.

You can remux the file into a .mp4 file quickly without any transcoding, and the index will be correct.

Get FLV Extract and mp4box.

Using FLV Extract, drag the saved .flv file from GetFLV 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, like this:

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

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

[borboleta]

Originally Posted by blimey

The index of the saved .flv file can be off. This may cause playability issues with some .flv players.

You can remux the file into a .mp4 file quickly without any transcoding, and the index will be correct.

Get FLV Extract and mp4box.

Using FLV Extract, drag the saved .flv file from GetFLV 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, like this:

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.

Great tutorial, blimey, I will try this method, it seems to me that the .mp4 file will have even better video and . acc audio than the original flv file. And I am sure it will play smoothly. Thanks for the help. It is always appreciated.

[borboleta]

I have been trying to get my original file to remux to the .mp4 format. The video and the audio are out of sync. I tried different fps values, the .mp4 file video and audio do not synchronize . I tried fps at 23.976, 29.976 and the average value from FLVExtract. I must be inputting the wrong fps value.Thanks for your help.

[borboleta]

Originally Posted by blimey

The framerate is either 23.976 or 29.970 for most hulu. I think all of the 3stooges are 23.976.

This method is for h264 source videos only. If the source video is VP6, this method won't work.

Thanks for your answer. I will try both fps and I will report the results. I have been trying the method in medium h264 and 1Mbps files.

[blimey]

Those are working for me. Check the command line carefully and also watch the text displayed by mp4box to be sure it is using your input framerate (it defaults to 25). Also check the output video file to be sure the framerate is the same as what you had on the command line.

[borboleta]

Originally Posted by blimey

I forgot to mention that when using rtmp.dll from 8.8.21, the index of the saved .flv file will be off. This may cause playability issues with some .flv players.

You can remux the file into a .mp4 file quickly without any transcoding, and the index will be correct.

I am sure you know of the freeware utility YAMB, the web site is: http://yamb.unite-video.com/, I tried it and it worked OK remuxing the file into a .mp4 file. The video and audio are synchronized.

I also have been lucky using the FileFactory utility you recommended, even though it uses transcoding. It does an excellent job., and in my case, the output file has greater video and audio quality than remuxing with Mp4box and YAMB. And I noticed less pixeling.
Thanks for the great help you have given us on this subject.

[blimey]

Originally Posted by borboleta

I am sure you know of the utility YAMB, the web site is: http://yamb.unite-video.com/, I tried it and it worked OK remuxing the file into a .mp4 file. The video and audio are synchronized. I also have been lucky using the FileFactory utility you recommended, even though it uses transcoding. It does an excellent job., and in my case, the output file has greater video and audio quality than remuxing with Mp4box and YAMB. And I noticed less pixeling. Thanks for the great help you have given us on this subject.

Interesting. What format do you convert to with Format Factory?

[borboleta]

Originally Posted by blimey

Interesting. What format do you convert to with format factory?

I use "All to MP4", and the program does it all, and I have tried all stream types, including the 1Mbps stream.

[greenbook]

I have tried to use the FLV Extract/mp4box tactic, but everytime I attempt to remux the .avi and .mp3 files with mp4box, it fails. The log file is below. There seems to an importing error. I don't know how to fix this and make the remux work.

[19:35:58] : Yamb 2.1.0.0 beta 2 started !!!

[19:35:58] : OS type detection...Windows XP Home Edition x86 (version 5.1, Build 2600 : Service Pack 3)

[19:35:58] : MP4Box found... C:\Documents and Settings\User\Desktop\MP4Box.exe

[19:35:58] : Tagger found...C:\Documents and Settings\User\Desktop\MP4Box.exe

[19:35:58] : MKVextract found...c:\documents and settings\user\application data\yamb\mkvextract\mkvextract.exe

[19:35:58] : EAC3to found...c:\documents and settings\user\application data\yamb\eac3to\eac3to.exe

[19:36:19] : tests.mp3 loaded.

[19:36:22] : tests.avi loaded.

[19:37:00] : Creation of tests.mp4...

[19:37:00] : Command Line used for Creation : "C:\Documents and Settings\User\Desktop\MP4Box.exe" -add "C:\Documents and Settings\User\Desktop\tests.avi#video:fps=8.926" -add "C:\Documents and Settings\User\Desktop\tests.mp3" -itags tool="Yamb 2.1.0.0 [http://yamb.unite-video.com]" "C:\Documents and Settings\User\Desktop\tests.mp4"

[19:37:00] : File saved in C:\Documents and Settings\User\Desktop\ 

[19:37:01] :  Error importing C:\Documents and Settings\User\Desktop\tests.avi#video:fps=8.926: Feature Not Supported

[19:37:01] : Creation failed.

[19:37:01] : Total Time Elapsed...

[19:37:12] : Yamb 2.1.0.0 beta 2 closed.

Originally Posted by greenbook

I have tried to use the FLV Extract/mp4box tactic, but everytime I attempt to remux the .avi and .mp3 files with mp4box, it fails. The log file is below. There seems to an importing error. I don't know how to fix this and make the remux work.

What video codec is used in your FLV files? How did you get AVI files from FLV files?