[flac-dev] About Decode Streaming

Tue Jul 2 02:01:13 PDT 2013

Martijn,

I don't use any metadata when encoding and decoding. When I call

*FLAC__StreamDecoderStateString[FLAC__stream_decoder_get_state(m_decoder)] *
*
*
it returns

FLAC__STREAM_DECODER_SEARCH_FOR_METADATA

enum value. Is it an error ?

2013/7/2 Burak Orçun Özkablan <borcunozkablan at gmail.com>

> Hi again,
>
> I can not solve problem. I want to mention my source code, so you may
> answer easily.
>
> This is decoder init stream function.
>
> *FLAC__stream_decoder_init_stream(m_decoder, decoderReadCallback, NULL,
> NULL, NULL, NULL, decoderWriteCallback, NULL, decoderErrorCallback,
> input_pile_array);*
> *
> *
> Then, callbacks
> *
> *
> /// \brief read callback function of decoder
> FLAC__StreamDecoderReadStatus decoderReadCallback(const
> FLAC__StreamDecoder *decoder,
>   FLAC__byte buffer[],
>   size_t *bytes,
>   void *callback_param
> );
>
> /// \brief write callback function of decoder
> FLAC__StreamDecoderWriteStatus decoderWriteCallback(const
> FLAC__StreamDecoder *decoder,
> const FLAC__Frame *frame,
>  const FLAC__int32 * const buffer[],
> void *callback_param
> );
>
> /// \brief error callback function of decoder
> void decoderErrorCallback(const FLAC__StreamDecoder *decoder,
>   FLAC__StreamDecoderErrorStatus status,
>   void *callback_param
> );
>
> When I call following statement,
>
> *// decode data*
> *if(!FLAC__stream_decoder_process_single(m_decoder))*
> * return;*
> *
> *
> firstly, read callback is called. In read callback function, I just use
> memory copy process.
>
> *// copy buffer array to m_pile_array*
> *if(input_pile_size > 0) {*
> * memcpy(input_pile_array, buffer, input_pile_size);*
> * input_pile_size = 0;*
> *
> *
> *
> *
> * return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;*
> *}*
> *
> *
> *return FLAC__STREAM_DECODER_READ_STATUS_ABORT;*
> *
> *
> and I wait for calling write callback but program throws LOST_SYNC
> exception. I don't know what causes.
>
>
> 2013/7/1 Burak Orçun Özkablan <borcunozkablan at gmail.com>
>
>> Sorry, I am newbie.
>>
>> Sample codes are from
>> https://github.com/oneman/libflac/tree/master/examples/cpp.
>>  I used FLAC__stream_decoder_process_single function but it still gives
>> exception. Maybe I could not control read callback, you're right.
>> I will check it and write result in this thread.
>>
>> Thanks for help.
>>
>>
>> 2013/7/1 Martijn van Beurden <mvanb1 at gmail.com>
>>
>>>  I'll top-post this one because it wasn't sent to the mailinglist but
>>> to me. Please reply to list next time.
>>>
>>> I assume you mean the main.c files in the encode and decode directory
>>> under examples. I can't really determine the root cause of your problem
>>> with this information, but I think you're trying to feed the decoder blocks
>>> that are incomplete. The LOST SYNC error is usually seen with corrupted
>>> blocks, so I think the blocks are incomplete or, less likely, corrupt.
>>>
>>> There are a few ways to counter this. The easy way is to add a little
>>> latency to be sure at least one complete block is in the receiving buffer.
>>> So, only call FLAC__stream_decoder_process_single() if the buffer is filled
>>> with enough data. If you want the lowest latency possible you could force a
>>> small block size or let the encoding PC signal the decoding PC when a block
>>> is finished, so the decoding process can be sure there is a full block in
>>> the buffer.
>>>
>>> Oh, and you might take a look at the reading callback, maybe that one is
>>> overreading the buffer?
>>>
>>> I hope that helps.
>>>
>>>
>>> On 01-07-13 17:51, Burak Orçun Özkablan wrote:
>>>
>>> Martijn,
>>>
>>>  I encode a one second captured audio data in my PC and send it to
>>> other PC as encoded. This is OK.
>>> I want to decode data in other PC and play it but when I am decoding
>>> data with decoder stream function, exception throws.
>>>
>>>
>>> 2013/7/1 Burak Orçun Özkablan <borcunozkablan at gmail.com>
>>>
>>>> Yes, I mean sample codes in FLAC directory. These samples (encode.c and
>>>> decode.c) are about encode/decode with file (using
>>>> FLAC__stream_encoder_init_file and FLAC__stream_decoder_init_file
>>>> functions).
>>>> Streaming which I used is audio data transfer over UDP or TCP sockets
>>>> of boost library.
>>>>
>>>>  I send 1 packet which contains 1 second "raw" audio data and header
>>>> information as unsigned char array. In the other PC, I play it. I must do
>>>> it continuously, so I said 'streaming' for this.
>>>> I can stream without FLAC library but I have to do with any codec
>>>> library because our network bandwidth is low so I dont want overhead
>>>> problem and latency.
>>>>
>>>>  For streaming, FLAC suggests streaming functions such as
>>>> FLAC__stream_encoder_init_stream, FLAC__stream_decoder_init_stream. The
>>>> decoder stream function takes 3 callback functions, write, read and error.
>>>> What I understand from LOST SYNC exception is write and read callback
>>>> must runs sync. I can not success it, code runs only reading callbacks and
>>>> throws LOST_SYNC exception.
>>>>
>>>>
>>>> 2013/7/1 Martijn van Beurden <mvanb1 at gmail.com>
>>>>
>>>>> On 01-07-13 16:48, Burak Orçun Özkablan wrote:
>>>>> > [...]
>>>>> >
>>>>> > I run your sample codes, encode.c and decode.c, about file encode /
>>>>> > decode. Then, I run
>>>>> > streaming encode / decode with two different source codes but when I
>>>>> > use streaming encode / decode over network in real-time, code throws
>>>>> > LOST_SYNC exception and only reading callback runs not writing
>>>>> > callback after exception.
>>>>>
>>>>>  I'm not sure I understand what you mean. You are talking about file
>>>>> encode and decode ans streaming encode and decode, do you mean the
>>>>> files
>>>>> in the FLAC source directory example? If so, what is the difference,
>>>>> because I only see file encoding examples?
>>>>>
>>>>> Furthermore, I wonder what you mean by stream. Are you serving a file
>>>>> that is being encoded over HTTP, S(a)MB(a), NFS or something specially
>>>>> designed for streaming, like MMS? So, how are you streaming the FLAC
>>>>> file?
>>>>>
>>>>> > How can I solve sync problem over network? Is it possible over
>>>>> network
>>>>> > or does FLAC stream with file?
>>>>>
>>>>>  FLAC is capable of streaming, so it should be possible to fix this I
>>>>> guess.
>>>>> _______________________________________________
>>>>> flac-dev mailing list
>>>>> flac-dev at xiph.org
>>>>> http://lists.xiph.org/mailman/listinfo/flac-dev
>>>>>
>>>>
>>>>
>>>>
>>>>   --
>>>>
>>>>
>>>>  Burak Orçun ÖZKABLAN
>>>>
>>>> Computer Science Engineer
>>>>
>>>>
>>>>  Mobile  : 0 541 302 18 78 <0%20541%20302%2018%2078>
>>>>
>>>>
>>>
>>>
>>>  --
>>>
>>>
>>>  Burak Orçun ÖZKABLAN
>>>
>>> Computer Science Engineer
>>>
>>>
>>>  Mobile  : 0 541 302 18 78
>>>
>>>
>>>
>>> _______________________________________________
>>> flac-dev mailing list
>>> flac-dev at xiph.org
>>> http://lists.xiph.org/mailman/listinfo/flac-dev
>>>
>>>
>>
>>
>> --
>>
>>
>> Burak Orçun ÖZKABLAN
>>
>> Computer Science Engineer
>>
>>
>> Mobile  : 0 541 302 18 78
>>
>>
>
>
> --
>
>
> Burak Orçun ÖZKABLAN
>
> Computer Science Engineer
>
>
> Mobile  : 0 541 302 18 78
>
>

-- 

Burak Orçun ÖZKABLAN

Computer Science Engineer

Mobile  : 0 541 302 18 78
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