[flac-dev] FLAC QUESTION

Rafael Velasquez rafaelvelasquez10 at gmail.com
Thu Apr 19 08:32:40 PDT 2012


Hello, in fact :
this error(FLAC__STREAM_ENCODER_VERIFY_MISMATCH_IN_AUDIO_DAT) occurs when
the sample size is bigger than the exepected size in the encoder.

Now, can someone tell me how to model the signal, for example :
*using a Fixed linear predictor for the input signal ? *


2012/4/13 Brian Willoughby <brianw at sounds.wa.com>

>
> On Apr 12, 2012, at 07:12, Rafael Velasquez wrote:
>
>> I'm using flac for an application.
>> The fact is that i'm trying to encode a file that is not necessary a wav
>> file.
>>
>> So, at first, i would like to know if it's possible to encode a file
>> different from the wav file with the flac encoder ?
>>
>
>
> First of all, the FLAC API does not work with WAV format data - you must
> provide raw audio samples.  If you have a WAV file, then you should use
> other code (your own?) to extract the raw audio samples from the file,
> leaving out the chunk headers and other, non-audio information.  You should
> also make sure that the FLAC object is initialized to accept the same size
> samples and channel count as you have in your data, and it would probably
> be a good idea to match the sample rate as well for proper decoding later.
>  Beware that the format you have may not exactly match what the FLAC
> library wants, so you may have to alter the data slightly before sending it
> to the API.
>
> So, it doesn't matter whether you have WAV, AIFF, SDII, or some other
> file, because your code must first extract the raw audio samples from the
> file before calling the FLAC library.
>
> Note that you can encode a WAV file as FLAC, and then later decode the
> FLAC file as AIFF.  FLAC does not usually care what the uncompressed
> foreign file format was (unless you use "preserve foreign metadata").
>  These operations are supported by the command-line program, but the WAV
> and AIFF format code is not part of the FLAC library.
>
>
>
>  When i put my data into : ok = FLAC__stream_encoder_process_**interleaved(encoder,
>> pcm, need);
>>
>> after some rounds in my boucl i get  :
>> encoding: FAILED
>>   state: FLAC__STREAM_ENCODER_VERIFY_**MISMATCH_IN_AUDIO_DATA   (<===
>> what does it really mean ? and what are the reasons to be in this case ? )
>>
>> I'm not english spoker, so sorry if i'm not very clear.
>>
>
> There is documentation for the FLAC API.  I do not see anything describing
> error messages, but you could look into the source code.  My guess is that
> "mismatch" refers to the checksum.  I do not have an answer for you here,
> but perhaps you can continue to work on your code and find the problem.
>
> Brian Willoughby
> Sound Consulting
>
>
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