Re: Re: Issue of Mpeg4 Audio (Newbe)
Re: Re: Issue of Mpeg4 Audio (Newbe)
- Subject: Re: Re: Issue of Mpeg4 Audio (Newbe)
- From: "ranjeet gupta" <email@hidden>
- Date: 7 Jul 2005 04:58:28 -0000
On Thu, 07 Jul 2005 William Stewart wrote :
>The AudioFile APIs that we provide in Mac OS X will play back (and create) these files in Tiger. So, you could take the AudioFileTools and use those tools (afconvert, afplay, etc) to read and write these files
My main work is to write the code and use the API from the ISO/SC29
Refrence Sofware Guide to play the m4a file, My Code is going
to play the file, with the help of the ISO/SC29 Refrence Sofware Guide
API, At present I am not able to find, Which Is going to seek the file
any idea on this ?
Ranjeet
>Bill
>
>On 06/07/2005, at 3:17 AM, ranjeet gupta wrote:
>
>>
>>
>>
>>On Wed, 06 Jul 2005 Stephen Davis wrote :
>> >Ranjeet,
>> >> I have the issue on the m4a (Mpeg 4 Audio), The basic thing what
>> >> I have to do is that I have to read the m4a audio and play back,
>> >>
>> >> The First basic thing I did is that, I copied all the data into >>the
>> >> new file i.e abcd.m4a as the copy_abcd.m4a and then playing the
>> >> file into the foobar player, I observaed that the copied file
>> >> i.e copy_abcd.m4a is playing fine,
>> >>
>> >> Now what I have to do is I have to play the file by skipping
>> >> some amount of the data, (Forward Skipping)
>> >>
>> >> so i skipped some amount of data (Here I skipped in terms of bytes),
>> >> and then made the file again names as the skipped_abcd.m4a, Now when
>> >> I play this file into the foobar then i see that it says about the
>> >> error, that it cannot play,
>> >MPEG-4 files are highly structured so you can't just hand a random >set of bytes from such a file to a decoder and expect it to work.
>>
>> yes, I came to know As i was going through the ISO/SC29 Refrence
>> Software Guide Version Is Dated 2000-08-08, For this I have been
>> given the source code for this, Is there any API present In this
>> Software guide which tells about how to skip the Audio of the
>> MP4 ?
>>
>> >> Again searched for the soulution of this, I came to know that
>> >> and read the site, and worked accoreding to it,
>> >> http://www.dv.co.yu/mpgscript/mpeghdr.htm
>> >This document describes MPEG-1 audio data. The MPEG-4 file format >is drastically different than this format.
>>
>>Thanks for giving your comment as I was also thinking the
>>same but was not sure.
>>
>> >
>> >I would suggest looking for ISO document "ISO/IEC 14496-3:2001" and >its siblings and going from there.
>>
>>I searched for the spec but it is payed one :-(
>>well I have ISO/SC29 Refrence Software guide so please do guide me
>>
>>Thanks
>>Ranjeet
>>
>> >stephen
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