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Rockbox mail archiveSubject: Re: how to merge fixed point wma decoder to libav 0.7.6Re: how to merge fixed point wma decoder to libav 0.7.6
From: Diaz Soho <soho123.2012_at_gmail.com>
Date: Thu, 11 Sep 2014 01:02:42 +0800 Hi Mike, Could you explain more detail about your idea? since I have question about how to decode wma file. the container used for wma file is ASF, how to demux asf in Rockbox? the data that read by asf_read_packet (to read an ASF packet) can be put into decode ,right? that does not include container data? Could you kindly give the hints? Thanks a lot!! 2014-09-03 1:45 GMT+08:00 Mike <giac2000_at_hotmail.com>: > There is no wrapper around ffmpeg for rockbox, the original ffmpeg code > has been rewritten to process data one frame at a time instead of one > superframe at a time like ffmpeg did. This was a problem on lower speed > devices because superframes could be very large, resulting in audio drop > outs. Actually, a large part of the original codec has been rewritten to > work better on low speed devices rather than PCs. > > Do you actually need the ffmpeg interface? I would probably not try to > use it here as it is not well suited to what you want to do unless your > embedded device is quite fast. Instead I would take a look at wma.c, which > does a very simple loop calling asf_read_packet (to read an ASF packet), > then wma_decode_superframe_init to prepare a superframe for decoding, > and finally a loop of wma_decode_superframe_frame that returns decoded > PCM samples. > > If you do need an ffmpeg interface, you could probably write a wrapper > around these functions. > > Mike > > ------------------------------ > Date: Wed, 3 Sep 2014 00:30:43 +0800 > Subject: Re: how to merge fixed point wma decoder to libav 0.7.6 > From: soho123.2012_at_gmail.com > To: rockbox-dev_at_cool.haxx.se > > but the usage of library seems different with original ffmpeg libav, > for example: > in rockbox, there is wma_decode_superframe_init, > but > in general ffmpeg libav does not include wma_decode_superframe_init, > > so, > > I do not got the point how to remove the wrapper that you add for rockbox > could you give some guide? > > > 2014-09-03 0:26 GMT+08:00 Mike <giac2000_at_hotmail.com>: > > The other option of course is to use our codecs directly. You can compile > the codeclib separately from Rockbox and call it directly from another > program or using the command line. We provide most of the same formats as > ffmpeg but all integer. > > ------------------------------ > From: giac2000_at_hotmail.com > To: rockbox-dev_at_cool.haxx.se > Subject: RE: how to merge fixed point wma decoder to libav 0.7.6 > Date: Tue, 2 Sep 2014 09:17:13 -0700 > > I talked to the ffmpeg people about it almost a decade ago. Since then > floating point hardware has become very common and the need for fixed point > diminished. The closest thing I can think of would be vlc for android > which uses an early version of our fixed point decoder that is still closer > to ffmpeg. > > Mike > > ------------------------------ > Date: Tue, 2 Sep 2014 17:32:00 +0800 > Subject: how to merge fixed point wma decoder to libav 0.7.6 > From: soho123.2012_at_gmail.com > To: rockbox-dev_at_cool.haxx.se > > Hi All, > > Is there anyone have idea about how to merge fixed point wma decoder to > libav 0.7.6? > because my cpu does not include fpu, when use the wma decoder in libav , > it take a lot of cpu time. > > Or is anyone have merge fixed point wma decoder to libav? > > > Thanks for any input!! > > > Received on 2014-09-10 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |