The only thing I can say is, that the results are different between the iPhone and desktop PC versions. In my case, the conversion had such a bad quality, that it was unusable. After that, I played with quality settings and such and got better quality as a result, but the produced file was then huge. Also try different output container formats, like .mov ... Experiment.
Or maybe you can check the ffmpeg source and arrive at your own conclusions. Please share them here. 2010/10/22 John Gladman <[email protected]>: > Hi Thomas > > Sorry to bother you again but I have created an App that executes the command > line functions as you suggested. > > When I run the App on the iPhone simulator, the mp4 file that is produced > is OK. > > When I run it on an iPhone the mp4 file has a green screen with distorted > images. The sound is OK. > > I did a Universal Build using the iFrameExtractor example as a base. > > Do you have any suggestions as to what this might be?? > > Thanks > > John > > > On 21 Oct 2010, at 21:08, Janez Zemva wrote: > >> Unfortunately, I don't have the sample anymore, but I can give hints: >> >> - you need to rename the main() function of ffmpeg.c to something else, >> - you need to provide some other "command-line" parameters, i.e. set >> the argv[] array elements to point to your custom "command line", >> - you need to compile the ffmpeg.c file as C source, set the file type >> in XCode to C source. >> >> Otherwise, ffmpeg.c, according to my memory, compiles cleanly, without >> any problems. Conversion proceeds at about 2-3 fps though and less on >> older iphones/ipods. >> >> 2010/10/21 John Gladman <[email protected]>: >>> Hi Thomas >>> >>> Would you mind sending me a skeleton iPhone APP that uses ffmpeg.c in this >>> way?? >>> >>> I have tried using a convert sample provided yesterday and am getting audio >>> file problems. But I can convert the AVI ok using a command line prompt. >>> >>> Best Wishes >>> >>> John Gladman >>> >>> >>> On 21 Oct 2010, at 17:42, Thomas Worth wrote: >>> >>>> On Thu, Oct 21, 2010 at 9:03 AM, Janez Zemva <[email protected]> wrote: >>>> >>>>> My approach to tackle this problem was to compile the entire ffmpeg.c >>>>> into my app and use it just like a command line utility within from my >>>>> application. The problem with this approach was, that while the use of >>>>> the ffmpeg utility is the same across all platforms. The results of >>>>> conversion certainly aren't (for all tested output formats). >>>>> Generally, the output of the same version ffmpeg, running on the >>>>> iphone, was worse, than the ouput of ffmpeg, running on the desktop >>>>> PC, using the same conversion parameters. >>>>> >>>>> 2010/10/20 ifrim alexandru <[email protected]>: >>>>>> --- On Wed, 10/20/10, John Gladman <[email protected]> wrote: >>>>>> >>>>>>> From: John Gladman <[email protected]> >>>>>>> Subject: Re: [libav-user] Using FFmpeg in iPhone Project >>>>>>> To: "Libav* user questions and discussions" <[email protected]> >>>>>>> Date: Wednesday, October 20, 2010, 1:56 PM >>>>>>> Hi >>>>>>> >>>>>>> What would it cost to provide a sample iPhone APP. I want >>>>>>> to convert a video file from AVI to an MP4 file that will >>>>>>> play on the iPhone. >>>>>>> >>>>>>> My problem is that I am currently creating an AVI file >>>>>>> within my APP but AVI files won't play on the iPhone. Thats >>>>>>> why I want to be able to convert it to >>>>>>> a format that will play on the iPhone. >>>>>>> >>>>>>> John G >>>>>>> >>>>>>> On 20 Oct 2010, at 18:50, Igor R wrote: >>>>>>> >>>>>>>>> Does anyone have a simple sample iPhone project >>>>>>> that allows video to be converted from one format to >>>>>>> another >>>>>>>> >>>>>>>> I don't have such a sample project, but I do develop >>>>>>> projects for >>>>>>>> iPhone with ffmpeg libs (libavcodec etc), and it >>>>>>> doesn't differ from >>>>>>>> using ffmpeg on Windows. Actually, we compile on >>>>>>> multiple platforms >>>>>>>> the same portable c++ code, which uses ffmpeg. >>>>>>>> _______________________________________________ >>>>>>>> libav-user mailing list >>>>>>>> [email protected] >>>>>>>> https://lists.mplayerhq.hu/mailman/listinfo/libav-user >>>>>>> >>>>>>> _______________________________________________ >>>>>>> libav-user mailing list >>>>>>> [email protected] >>>>>>> https://lists.mplayerhq.hu/mailman/listinfo/libav-user >>>>>>> >>>>>> >>>>>> As Igor mentioned the code is the same as on other platforms, but here's >>>>> a sample (from what I remember it was working correctly, I haven't >>>>> used/tested it much though). To convert to mpeg4 you'll need to make some >>>>> changes (it requires some strict parameters from what I recall). >>>>> >>>> >>>> There's a lot of assembly code in FFmpeg, which is CPU-specific. I assume >>>> this could cause one platform to behave differently than another, and even >>>> within the same platform depending on the compiler. For example, from what >>>> I >>>> understand the Intel C compiler does a better job at optimizing x86 code >>>> than GCC (while sacrificing strict compliance, perhaps), but all of this is >>>> moot if it's already written in assembly. Someone please correct me if I'm >>>> wrong. Thanks. >>>> _______________________________________________ >>>> libav-user mailing list >>>> [email protected] >>>> https://lists.mplayerhq.hu/mailman/listinfo/libav-user >>> >>> >> _______________________________________________ >> libav-user mailing list >> [email protected] >> https://lists.mplayerhq.hu/mailman/listinfo/libav-user > > _______________________________________________ > libav-user mailing list > [email protected] > https://lists.mplayerhq.hu/mailman/listinfo/libav-user > _______________________________________________ libav-user mailing list [email protected] https://lists.mplayerhq.hu/mailman/listinfo/libav-user
