Posted: Mon 17 Nov 2014, 03:54 Post_subject:
Losslessly convert FLV to MP4 Sub_title: Tools for handling those undf videos.
If you happen to gather flv video from say the /tmp folder or elsewhere on the net you probably have come across the problem that some video players don't like them or have problems navigating through them.
Been trying out this which seems to work a treat and produces an mp4 that even me olde vlc 0.8.6 gets on with.
There are ways with ffmpeg but this is another fast approach plus links for the tools which are a little elusive on linux or special builds.
1. split the video using
FLVExtractCL -v -a INPUT.flv
flvextract -v -a INPUT.flv
for the python version
The result is a 264 and aac file....
2. Join them...
MP4Box -add INPUT.h264:fps=25.000 -add INPUT.aac OUTPUT.mp4
the fps is important...flvextract will give you the figure...this keeps sound in sync happily.
Done...one nicely playable no hidden codec definitions scrollable mp4 in the time it takes to read and write the files. Yes you do need room to pack and unpack the stuff...MP4box uses /root(pwd) by default but thats changeable. with the -tmp option....handy if you have a small save file for example.
Ok tools... not really petable stuff since what you use and what you have will vary.
Joined: 10 Feb 2014 Posts: 342 Location: Pune, India.
Posted: Mon 17 Nov 2014, 10:22 Post_subject:
I have some 'undf' videos which were given by friends but their extension say mp4. I don't know how he downloaded them from tube. maybe they were flv and because of not playing he may have changed their extension to mp4 to see if it works.
I will play with this tool on Fatdog.
- Neeraj. _________________ "One of my most productive days was throwing away 1000 lines of code."— Ken Thompson
Yes...one site I originally tried this on had the .avi extension.... but a hex editor showed them to be flv.
Apart from the undf usually you cannot scroll through them either .... just rename to .flv to avoid confusion.
They mainly appear when you watch on say you tube with older flashplayer and you use the temporary file in /tmp.... they have hidden the codec info but flashplayer is ok because it only expects certain formats anyway....h264/aac was the later flv format for flash after soreson spark. After that they went to true mp4 handling and vp8 I think but that seems to have remained unpopular...cos its crap lol. A you tube downloader will get you a true mp4/webm or whatever.