Shuffle around some checks for resampling config

BytesPerSample and NeedsResample were getting set when an unsupported
conversion was requests, which resulted in things breaking when the
caller later tried to request unresampled data.

src/core/audiosource.cpp

@@ -192,23 +192,25 @@ void FFMS_AudioSource::SetOutputFormat(const FFMS_ResampleOptions *opt) {
 		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_USER,
 			"Cannot change the output format after audio decoding has begun");
 
-	BytesPerSample = av_get_bytes_per_sample(static_cast<AVSampleFormat>(opt->SampleFormat)) * av_get_channel_layout_nb_channels(opt->ChannelLayout);
+	if (opt->SampleRate != AP.SampleRate)
+		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
+			"Sample rate changes are currently unsupported.");
 
+#ifndef WITH_AVRESAMPLE
+	if (opt->SampleFormat != AP.SampleFormat || opt->SampleRate != AP.SampleRate || opt->ChannelLayout != AP.ChannelLayout)
+		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
+			"FFMS was not built with resampling enabled. The only supported conversion is interleaving planar audio.");
+#endif
+
+	BytesPerSample = av_get_bytes_per_sample(static_cast<AVSampleFormat>(opt->SampleFormat)) * av_get_channel_layout_nb_channels(opt->ChannelLayout);
 	NeedsResample =
 		opt->SampleFormat != (int)CodecContext->sample_fmt ||
 		opt->SampleRate != AP.SampleRate ||
 		opt->ChannelLayout != AP.ChannelLayout ||
 		opt->ForceResample;
-	if (!NeedsResample) return;
-
-	if (opt->SampleRate != AP.SampleRate)
-		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
-			"Sample rate changes are currently unsupported.");
 
 #ifdef WITH_AVRESAMPLE
-	if (opt->SampleRate != AP.SampleRate)
-		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
-			"Changing the audio sample rate is currently not supported");
+	if (!NeedsResample) return;
 
 	std::auto_ptr<FFMS_ResampleOptions> oldOptions(ReadOptions(ResampleContext, resample_options));
 	SetOptions(opt, ResampleContext, resample_options);
@@ -222,10 +224,6 @@ void FFMS_AudioSource::SetOutputFormat(const FFMS_ResampleOptions *opt) {
 		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNKNOWN,
 			"Could not open avresample context");
 	}
-#else
-	if (opt->SampleFormat != AP.SampleFormat || opt->SampleRate != AP.SampleRate || opt->ChannelLayout != AP.ChannelLayout)
-		throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
-			"FFMS was not built with resampling enabled. The only supported conversion is interleaving planar audio.");
 #endif
 }