[gst-devel] problem using alawdec

[Tiago Katcipis]

i made a huge mistake, sorry. Endianess will not solve my problem.

what i need is
0xABCD -> SWAP -> 0xCDAB

what endianness will do is
0xABCD -> ENDIANESS -> 0xDCBA

if i am mistake...again :-), someone please let me know.

Is there any element to do byte swapping? its very simple i know, but i just
dont want to redo something that already exists.

Sorry for the newbieness, and thanks for the help.

best regards,
Katcipis

On Mon, Jul 13, 2009 at 3:40 PM, Tiago Katcipis <katcipis at inf.ufsc.br>wrote:

> Its not 16 bit alaw, i have to swap every 2 bytes, so i tell the
> audioconvert to get a sample of 16bits and swap it from 4321 to 1234. so the
> bytes (alaw samples) will be on the right position. I know its kinda odd,
> but my alaw file has the samples on the wrong order, so the bytes must be
> swaped, something like swap byte[0] with byte[1], byte[2] with byte[3]...and
> so goes on. I know i can make a element to do this, but i was trying to
> already use what is already done to acomplish the swaping.
>
> Its not a endianess problem, its the alaw samples that are on the wrong
> order, i just use the audioconvert endianess to try to swap the samples for
> me.
>
> On Mon, Jul 13, 2009 at 2:30 PM, Michael Smith <msmith at xiph.org> wrote:
>
>> On Mon, Jul 13, 2009 at 8:54 AM, Tiago Katcipis<katcipis at inf.ufsc.br>
>> wrote:
>> > I have a file that is alaw encoded, but the file has the bytes swaped,
>> every
>> > two bytes must be swaped so the alaw decoder can decode properly. I
>> started
>> > to try to build a pipe but i got stuck.
>> >
>> > The pipe:
>> >
>> > gst-launch -v filesrc location=alaw_inv.dat ! audio/x-raw-int,
>> > endianness=4321, channels=1, rate=8000, width=16, depth=16, signed=false
>> !
>> > audioconvert ! audio/x-raw-int, endianess=1234, channels=1, rate=8000,
>> > width=16, depth=16, signed=false ! queue ! audio/x-alaw, rate=8000,
>> > channels=1 ! alawdec ! audioconvert ! wavenc ! filesink
>> > location=exemplo_convertido.
>> > wav
>>
>> This won't work, because audioconvert won't just do byteswapping on
>> unknown data, which is basically what you want.
>>
>> It also won't work because you seem to have 16 bit a-law? GStreamer's
>> alaw decoder doesn't support that; I've never heard of it being used -
>> are you sure it's a-law? Regardless, you'll need a special decoder.
>>
>> Once you have written a decoder for this format, you can make that
>> decoder accept the endianness your data is in, so you don't need to
>> byteswap beforehand.
>>
>> Mike
>>
>>
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>
>
>
> --
> "it might be a profitable thing to learn Java, but it has no intellectual
> value whatsoever" Alexander Stepanov
>



-- 
"it might be a profitable thing to learn Java, but it has no intellectual
value whatsoever" Alexander Stepanov
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