When importing MP3s, read encoder delay and padding information from Xing/Info tag (and equivalents for other encoders) in order to embed the MP3 gaplessly. It will also be necessary to discard broken MP3 frames, ID3 tags and other junk data.
The samples attribute of DefineSound needs to be set to the length of the original audio, which can be calculated as frames * frame_length - encoder_delay - padding.
The first two bytes of sound data (SeekSamples) form a 16-bit signed integer, which is currently always 0. Instead, it should be set to encoder_delay + decoder_delay.
Flash uses the Fraunhofer decoder internally, so decoder_delay is 529 samples.
When importing MP3s, read encoder delay and padding information from Xing/Info tag (and equivalents for other encoders) in order to embed the MP3 gaplessly. It will also be necessary to discard broken MP3 frames, ID3 tags and other junk data.
samplesattribute ofDefineSoundneeds to be set to the length of the original audio, which can be calculated asframes * frame_length - encoder_delay - padding.SeekSamples) form a 16-bit signed integer, which is currently always0. Instead, it should be set toencoder_delay + decoder_delay.Flash uses the Fraunhofer decoder internally, so
decoder_delayis 529 samples.I’ve written some code to do this in the Flex compiler, which can be adapted: https://github.com/djcsdy/flex-extensions/blob/master/src/net/noiseinstitute/flexextensions/compiler/media/mp3/MP3TranscodeJob.java