Rockbox mail archiveSubject: Re: LOW_WATER and high bitrates
From: Uwe Freese (mail_at_uwe-freese.de)
Nielsen Linus (ext) wrote on Thursday, August 1, 2002, 7:40:46 AM:
>> How can I find the beginning of an mp3-frame (and find the header)?
NLe> You will have to search the bitstream for a frame sync word. First
I don't know if it takes this long to search for the sync words. Maybe
NLe> Secondly, we don't have floating point support. This CPU has no
I didn't know that. But I'm sure it's possible with ints, too.
>> The playing time should also be updated while playing the song.
NLe> What firmware are you using? We have been displaying play time for
Is the playing time written somewhere in the mp3 file or calculated by
>> I'd prefer this instead of reading in the whole file before
NLe> What makes you think we read the whole file before playing it?
Is my english so bad? ;) I know that we don't do this now.
To calculate an average bitrate (my whole mail was about that), we can
1. read sync words, bitrates in mp3frames and calculate an average so
2. read the whole file before playing as described in id3.c:
* Calculates the length (in milliseconds) of an MP3 file. Currently this code
And I find the first solution better.
>> And I think it'll give a really good average value very quickly.
NLe> No, that is taken care of dynamically by the decoder DSP,
The DSP plays the stream without us saying him the bitrate of the mp3
Page was last modified "Jan 10 2012" The Rockbox Crew