![]() Without it, the seeking algorithm needs to guess the most probable file offset, perform a file read from this position, find an audio frame, get its audio position and if it's not the frame we're looking for, repeat the same algorithm over and over again until the needed frame is found. Having a seek table is vital for a fast seeking within a large stream with a non-linear distribution of audio data. ![]() Using seek table one can find in which place within the file the needed audio is stored. For a constant-bitrate stream like WAVE and MP3 CBR it's easy to find the needed audio frame in just one file seek request.īut for a variable-bitrate stream a so called "seek table" must be used to achieve faster seeking. To seek on an audio file it's required to convert the audio sample number into a file position where the needed audio data is stored. Whether it's possible to effectively find within a physical stream an audio frame containing the target audio sample. WavPack supports lossy audio as well as lossless. MP4 may contain lossless (ALAC) and lossy (AAC) audio. Such encoder works similar to the way how ZIP packer compresses text files, so after you unpack it the text is exactly the same as it was: without any words missing or letters interchanged. A lossless audio encoder compresses audio in a way that after decompression you'll have a 100% quality audio, exactly as the original source. Whether a format supports lossless audio. More details and notes on each aspect: Lossless They all have their similarities and differences, so the table below gathers everything together. Audio data compressed with one of the codec listed above is stored within an audio file, each codec uses its own data container format. In this section I present to you the comparison of audio file formats. However, the same sources also claim that for AAC there's a big difference in sound quality between files produced by different encoders, and that libfdk-aac has quite good quality. In other words, to achieve the same quality of MP3's 320kbps, Vorbis and AAC require less bitrate value, e.g. Although these numbers were produced by fmedia, other audio tools show very similar decoding performance.Īs for lossy codecs, I can't show any proof, but other sources claim that sound quality of Vorbis and AAC are better than MPEG-1 Layer-3 for the same bitrate. However, decoding speed is different: FLAC is almost 3 times faster than WavPack and 6 times faster than APE. Actually, there is a very small amount of time required to read and write WAVE files, but I chose not to include it here, because it only shows the speed of system memory and disk.Īll lossless codecs have similar compression ratio. This is an average value of all tests shown below, read section "Performance Tests" for more details.Īudio data inside a WAVE file is stored uncompressed, it doesn't require any decoding or encoding work to do, therefore its compression ratio is 1:1 and the speed is unlimited. This table shows the short summary information about audio formats and accumulated results of the performance tests.Ĭompression Ratio: the difference between uncompressed and compressed file, applies to Lossless only, the lower - the better.ĭecoding/Encoding Speed shows how many audio samples are processed per time unit, the higher - the better. ![]() However, this document can help you to decide which audio format is more suitable for your needs. I think it's impossible to pick the best format for *every* use, especially from lossy audio formats. This article doesn't claim which audio format is the best and which is the worst, because to do that it would require to test each format with a wide variety of music, with a large variety of audio settings (encoder settings, audio format), with different codec implementations and on different hardware. In the end of this article I'll describe how you can perform similar tests by yourself. There is information about file formats that are used for storing audio data, meta tags supported by different file formats and the results of some performance tests. It covers lossless (FLAC, ALAC, APE, WavPack) and lossy audio codecs (Vorbis, Opus, MPEG, AAC, Musepack). The goal of this article is to show the differences between several audio formats and codecs.
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