[mad-dev] errors and MAD_RECOVERABLE()
Tue, 14 May 2002 16:56:51 -0700
On Tuesday, May 14, 2002, at 03:23 AM, Thomas Rathbone wrote:
> Using the high level API. In the error callback if
> MAD_RECOVERABLE(stream->error) returns true how do I deal with the error?
> Do I just report the error and return MAD_FLOW_CONTINUE? Will madlib
> recover the error itself or do I have to fix the error before resuming?
When using the high-level API, the error callback is called when a
decoding error occurs ONLY if MAD_RECOVERABLE(stream->error) is true. You
need not perform any specific action; usually the only thing you may want
to do is report the error. The value you return determines what the
decoder does next:
MAD_FLOW_STOP: The decoder ends its decoding loop and returns normally.
MAD_FLOW_BREAK: The decoder ends its decoding loop and returns abnormally.
MAD_FLOW_IGNORE: As long as the frame's header was successfully decoded,
the decoder ignores the error and proceeds with the filter callback and
synthesis. In this case you should arrange to have the desired subband
samples for synthesis in the frame structure, for example, by leaving the
previous frame's samples, or by muting the samples by calling
MAD_FLOW_CONTINUE: The decoder proceeds to the next frame, skipping the
frame which caused the error.
If you don't specify an error callback (by passing a null pointer), the
default action is as follows: If the error is MAD_ERROR_BADCRC, then
either leave the previous frame's subband samples in the frame, or mute
the frame if the previous frame had the same error, and then ignore the
error (proceeding with the filter callback and synthesis). In the case of
any other error, skip the frame and proceed with the next frame.
The errors which are not recoverable include:
MAD_ERROR_BUFLEN - stream buffer needs refilling
MAD_ERROR_BUFPTR - invalid buffer pointer
MAD_ERROR_NOMEM - required memory could not be allocated
In these cases the high-level decoder will either call your input callback
to refill the stream buffer, or terminate with an error.