flv流解码，3gp编码

Question

Are there any open source projects in any language and other recourses that I need to look at in order to implement flv to 3gp conversion? It's better to be streaming, I mean return first portion of 3gp before last portion of flv is downloaded.

Or are there any similar services already implemented - my goal is to have something like http://converter.org?source=sourceUrl.flv&targetFormat=3gp that I can feed to 3gp player, in my case - on iPhone, and not wait until server downloads entire flv.

UPDATE: ffmpeg does really good job here, just

ffmpeg -i input.flv output.mp4

and that's it. But output file can be used only after conversion is done. Streaming is still an open question. There is ffserver that does some sort of streaming but I could not make it work.

Answer 1

I'm not sure if it is possible, but if there's one thing that should do it. it's http://www.ffmpeg.org/ ..

it can convert anything to anything on an online platform. don't know if it supports streaming but definitely the best solution for online video conversion

Answer 2

Well this one might be a little late to the party but to stream video online you'll need a Media Streaming Server to deliver the video over a specific streaming protocol (ie HTTP,HTTPS,RTSP,RTMP). I've also been looking for such a "real-time" transcoding service but the closest thing I've found so far is the Video CDN's which are quite pricy, and also limited in formats/support. What would be really nice is for one of the media servers to add in a real-time transcoding feature. At the time of this writing no such service exists that I know of.

The top 10 most popular options for Media Streaming Servers are (IMHO):

1. VideoLAN - VLC Media Player (good for quick tests and proof-of-concept)
2. Kaltura - Open Source video platform
3. Real Media - Helix Universal Streaming Server (may be best bet for 3GP over RTSP)
4. Apple - Darwin Streaming Server / Quicktime (Live) Broadcaster (best for iPhone/iPad)
5. Red5 - Open Source Flash Streaming Server
6. Adobe - Flash Streaming Server
7. Wowza - Media Server
8. FluMotion - Open Source Multimedia Streaming
9. Microsoft - Windows Media Server ( AVI , WMV , Silverlight & other formats)
10. FreeCast - An OGG Theoris (video) and OGG (audio) streaming/conversion platform

As you can see there are many options for streaming and you can start as simply as hosting the video on the same server and delivering to Desktop computer browsers via HTTP (the easiest way to get started with this is trial & error). Each offers different features in terms of protocols supported and transcoding, but none are truly real-time as you mention where you could feed in a source video and get an output video in the format of you choosing (ie 3GP). My personal choice would be to start with VLC for small-scale tests on a home network, since it is basically a swiss-army knife for desktop video that can also act as a server for any of the formats it can playback (though it may be more complicated to get this to stream to the public internet and even harder to go all the way to a single device on a private carrier network, some info is available from people who've tried): http://forum.videolan.org/viewtopic.php?f=4&t=45782

Some basic transcoding instructions to go to MP4 (required for iPhone/iPad/iPods): http://wiki.videolan.org/MPEG-4

I also agree about FFMPEG being by far the best solution for video conversion, as it also supports 3GP and you can at least start playing around with conversion on your own test server, you might want to try the following PHP Classes project: http://www.phpclasses.org/package/5977-PHP-Manipulate-video-files-using-the-ffmpeg-program.html

In my experience that was an excellent contribution to speed web interaction with FFMPEG's mostly command-line and sometimes clunky interface. Who knows, maybe you'll build the first real-time transcoding service, I'd be the first to signup as a customer and/or as a contributor to help you on that!