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Can't find documentation

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Ali Hamdi

Can't find documentation

Hi,

I was just wondering where I could find documentation about the data packing used in the raw-audio (specifically 32-bits stereo raw-int). I want to be able to extract data to external software to analyze, meaning I want to be able to parse a binary file to proper waveforms, which is why I need to know how to put the bytes together again to proper quantization samples. Been doing some trial and error, with no luck so far..

Thank you in advance.

Best regards
Ali

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Stefan Sauer

Re: Can't find documentation

Ali Hamdi schrieb:
> Hi,
>
> I was just wondering where I could find documentation about the data packing used in the raw-audio (specifically 32-bits stereo raw-int). I want to be able to extract data to external software to analyze, meaning I want to be able to parse a binary file to proper waveforms, which is why I need to know how to put the bytes together again to proper quantization samples. Been doing some trial and error, with no luck so far..

Channels are interleaved. for stereo you'll get one left, one right (hopefully I
got the order right). Are you sure you want 32bit int audio? Thats quite unusual
and most elements won't output that. You can always use audioconvert and a caps
filter to request this format though. If you ask for "audio/x-raw-int, depth=32,
width=32, channels=2, signed=true" then you get a gint32 for each sample value.

Stefan

>
> Thank you in advance.
>
> Best regards
> Ali
>
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> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel

Ali Hamdi

Re: Can't find documentation

First of all, thank you alot for your help :)

One question though: Are they interleaved in total, meaning that the whole sample are sequential in bytes or are they split up bytewise in some order? The reason I'm asking is that they seem to be split in some way judging by the results, and by this reference (which is referring to 24-bit pcm though): http://wiki.multimedia.cx/index.php?title=PCM

Regarding the format, this is what the output is from decodebin2 according to one instance of typefind, is this not correct?

And a big thanks again for your reply.

/Ali

________________________________________
Från: Stefan Kost [[hidden email]]
Skickat: den 3 april 2009 21:13
Till: Discussion of the development of GStreamer
Ämne: Re: [gst-devel] Can't find documentation

Ali Hamdi schrieb:
> Hi,
>
> I was just wondering where I could find documentation about the data packing used in the raw-audio (specifically 32-bits stereo raw-int). I want to be able to extract data to external software to analyze, meaning I want to be able to parse a binary file to proper waveforms, which is why I need to know how to put the bytes together again to proper quantization samples. Been doing some trial and error, with no luck so far..

Channels are interleaved. for stereo you'll get one left, one right (hopefully I
got the order right). Are you sure you want 32bit int audio? Thats quite unusual
and most elements won't output that. You can always use audioconvert and a caps
filter to request this format though. If you ask for "audio/x-raw-int, depth=32,
width=32, channels=2, signed=true" then you get a gint32 for each sample value.

Stefan

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Stefan Sauer

Re: Can't find documentation

Ali Hamdi schrieb:
> First of all, thank you alot for your help :)
>
> One question though: Are they interleaved in total, meaning that the whole sample are sequential in bytes or are they split up bytewise in some order? The reason I'm asking is that they seem to be split in some way judging by the results, and by this reference (which is referring to 24-bit pcm though): http://wiki.multimedia.cx/index.php?title=PCM
>
Its always complete samples. There can be the case width=32, depth=24,
where the samples would be stores as 32 bit, but only 24 bits are real
data. This is quite common for 24bit pcm audio as without padding its
cumbersome to address samples.

> Regarding the format, this is what the output is from decodebin2 according to one instance of typefind, is this not correct?
>
I don't understand the question.
Stefan

> And a big thanks again for your reply.
>
> /Ali
>
> ________________________________________
> Från: Stefan Kost [[hidden email]]
> Skickat: den 3 april 2009 21:13
> Till: Discussion of the development of GStreamer
> Ämne: Re: [gst-devel] Can't find documentation
>
> Ali Hamdi schrieb:
>
>> Hi,
>>
>> I was just wondering where I could find documentation about the data packing used in the raw-audio (specifically 32-bits stereo raw-int). I want to be able to extract data to external software to analyze, meaning I want to be able to parse a binary file to proper waveforms, which is why I need to know how to put the bytes together again to proper quantization samples. Been doing some trial and error, with no luck so far..
>>
>
> Channels are interleaved. for stereo you'll get one left, one right (hopefully I
> got the order right). Are you sure you want 32bit int audio? Thats quite unusual
> and most elements won't output that. You can always use audioconvert and a caps
> filter to request this format though. If you ask for "audio/x-raw-int, depth=32,
> width=32, channels=2, signed=true" then you get a gint32 for each sample value.
>
> Stefan
>
>
>> Thank you in advance.
>>
>> Best regards
>> Ali
>>
>> ------------------------------------------------------------------------------
>> _______________________________________________
>> gstreamer-devel mailing list
>> [hidden email]
>> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>>
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>

Ali Hamdi

Re: Can't find documentation

Ok, I see. About the question, I tried using decodebin2 to decode an mp3-file, and then I had typefind-element right after decodebin2 and printed what type the element found. The type found (without any filter) was a 32-bit depth and width raw-int. Thats why I wanted to be able to parse this format. However, I tried using audioconvert and a caps filter like you wrote, and it worked perfectly. So thanks again for all your help. :)

/Ali
________________________________________
Från: Stefan Kost [[hidden email]]
Skickat: den 7 april 2009 17:15
Till: Discussion of the development of GStreamer
Ämne: Re: [gst-devel] Can't find documentation

Ali Hamdi schrieb:
> First of all, thank you alot for your help :)
>
> One question though: Are they interleaved in total, meaning that the whole sample are sequential in bytes or are they split up bytewise in some order? The reason I'm asking is that they seem to be split in some way judging by the results, and by this reference (which is referring to 24-bit pcm though): http://wiki.multimedia.cx/index.php?title=PCM
>
Its always complete samples. There can be the case width=32, depth=24,
where the samples would be stores as 32 bit, but only 24 bits are real
data. This is quite common for 24bit pcm audio as without padding its
cumbersome to address samples.

> Regarding the format, this is what the output is from decodebin2 according to one instance of typefind, is this not correct?
>
I don't understand the question.
Stefan

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