Programmatically convert a video to FLV [closed]

问题:

i am currently working on a web application that needs to accept video uploaded by users in any format (.avi, .mov, etc.) and convert them to flv for playing in a flash-based player.

Since the site is OpenCms-based, the best solution would be a ready-made plugin for OpenCms that allowed to upload and play videos doing the transcode operation in background, but just a set of Java classes to do the transcode would be great and then i could make the uploading form and playback part on my own.

回答1:

You basically have two choices if you want to host, transcode and stream flv files (and don't want to buy a video transcoding application): you can call out to FFMpeg/MEncoder or you can use an external Web service. You could also sidestep the problem completely by allowing them to embed YouTube videos on your site.

If you go the 'local FFMpeg route' I would suggest simply using ProcessBuilder and constructing a command-line to execute FFMpeg. That way you get full control over what gets executed, you avoid JNI, which is an absolute nightmare to work with, and you keep OS-specific code out of your app. You can find FFMPeg with all the bells and whistles for pretty much any platform. There's a good chance it's already on your server.

The nice thing about the 'Local FFMPeg' route is that you don't have to pay for any extra hosting, and everything is running locally, although your hosting admin might start complaining if you're using a crazy amount of disk and CPU. There are some other StackOverflow questions that talk about some of the gotchas using FFMpeg to create flvs that you can actually play in the flash player.

The Web service route is nice because there is less setup involved. I have not used Hey!Watch but it looks promising. PandaStream is easy to set up and it works well, plus you get all your videos on S3 with no additional effort.

回答2:

There's a great open source tool call FFmpeg that I use to transcode my videos. I use PHP making shell calls to make it come to life, but I can't imagine that it would be too hard to get it to play nice with Java. (Maybe this could be a good starting point for you.)

I feed my installation 30+ gig batches on a weekly basis and it always comes out as quality material. The only tricky part for me has been getting it compiled to handle a wide variety of video formats. On the bright side, this has provided me with heavy lifting I need.

回答3:

You can encode video in Java using Xuggler, which is a Java API that natively uses FFmpeg's C code behind the scenes.

回答4:

This can be slightly tangential, but I have found Panda Stream to be a very useful solution to all kinds of video encoding problems.

All you have to do is to upload the video file to an Amazon EC2 instance running Panda and it will encode the video to your desired formats and quality and will issue a callback to your application server with the details when it's done. You can then use the bundled Flash Video player or your own player to play the videos on your site.

It's a very scalable (thanks to Amazon EC2 & S3), cost-effective and customisable solution compared to rolling your own.

Highly recommended.

Update:

The architecture of Panda is as follows:

Architecture of Panda Stream http://pandastream.com/images/panda_arch.gif

1. Page displays Panda's upload form in an iframe or popup
2. Video upload with AJAX progress bar
3. API callback when encoding is complete
4. Video streamed to user

回答5:

There is an open source library used by MPlayer, called mencoder, wich supports FLV, as well as a lot of other codecs.

There is a Java GUI you could see how was made

This could help too.

I don't seem to be able to find any example not called from the console, so it may not be usefull for you. :S

Edit Also take a look at this question.

回答6:

You could try using an online service like HeyWatch to convert your video. Never used it but they claim

"transparent upload, send videos transparently from your website"

Not a java solution, but you wouldn't have to worry about what OS your web application is on.

If OS wasn't an issue I agree with the answer theBadDawg gave. I don't know of and have had not any luck finding a pure java solution.

回答7:

Encoding files in one format to another takes a lot of development time to get right, which is why there is so little in terms of decoders/encoders that are able to accomplish those feats. The ones that are well known and used the most are ffmpeg and mencoder.

What you may want to look into is to see if the platform you are running on (Windows/Mac OS X/Other unix) has an underlying set of API calls you can use that is able to decode the files, and re-encode them. Windows has DirectShow and Mac OS X has Quicktime. Not sure if you can access those API's using Java though.

FFMpeg does have a Java wrapper available: FFMPEG Java, and there is also FOBS which has a JNI available for their C++ wrapper around ffmpeg. The last one that I found jFFmpeg, however there are some posts that I found with Google suggesting that the project may not be alive any longer.

Your best bet would be either mencoder from mplayer and or ffmpeg. Ffmpeg can be installed as a separate binary and then called from other code using the default "shell" commands. If you are however not able to execute commands you may need to look at using an online conversion website like Mark Robinson suggested.

回答8:

FFMpeg is the best when it comes to video transcoding.

You can use java wrappers for ffmpeg - http://fmj-sf.net/ffmpeg-java/getting_started.php http://sourceforge.net/projects/jffmpeg/

回答9:

If you want to do it with java, you can do it very easily using Xuggle.

They have a great website explaining how to do everything

the documentation is here: http://build.xuggle.com/view/Stable/job/xuggler_jdk5_stable/javadoc/java/api/index.html

and an excellent tutorial telling you how to do what you want is here: http: //blog.xuggle.com/2009/06/05/introduction-to-xuggler-mediatools/

They provide an easy way to do what you want in the first tutorial, which is simple trans-coding.

I've found that it works alright for encoding to flv. What it does behind the scenes is use ffmpeg, so anything that will trip up ffmpeg will also fail with xuggle.

The relevant sample java code is:

 // create a media reader
 IMediaReader reader = ToolFactory.makeReader("videofile.flv");

 // add a viewer to the reader, to see the decoded media
 reader.addListener(ToolFactory.makeWriter("output.mov", reader));

 // read and decode packets from the source file and
 // and dispatch decoded audio and video to the writer
 while (reader.readPacket() == null)
   ;

Which I got from http ://wiki.xuggle.com/MediaTool_Introduction

If you want some fully working clojure code... here it is :)

(import '(com.xuggle.mediatool ToolFactory))
(import '(com.xuggle.mediatool IMediaDebugListener IMediaDebugListener$Event))

    (defn readerRecurse
      "calls .readPacket until there's nothing left to do2"
      [reader]
      (if (not (nil? (.readPacket reader))) ; here .readPacket actually does the processing as a side-effect.
        true                                   ; it returns null when it has MORE ro process, and signals an error when done... 
        (recur reader)))


    (defn convert
      "takes video and converts it to a new type of video"
      [videoInput videoOutput]
      (let [reader (ToolFactory/makeReader videoInput)]
        (doto reader
          (.addListener (ToolFactory/makeWriter videoOutput reader))
          (.addListener (ToolFactory/makeDebugListener (into-array [IMediaDebugListener$Event/META_DATA]))))
        (readerRecurse reader)))

now all you have to do is something like:

(convert "/path/to/some_file.stupid_extention" "/path/to/awesome.flv")

and you're done!

回答10:

You might also be interested in hearing that we've now released Panda as a hosted service as well, which makes the setup and scaling easier :)

http://pandastream.com

回答11:

yea, ffmpeg is the best for this work...We use ffmpeg to convert video for a long time and it works with all video formats..numerous options are there..