Most cars can recognize that the song format in the USB flash drive is MP3, but MP3 is not the only format.

Take BMW as an example:

The music formats that BMW can play include MP3, WMA, AAC, wav and flac, but APE cannot.

In the process of music transfer, the BMW CIC host will convert the original MP3 and other format files into "BR5" format files and store them in the host hard disk. BR5 format files cannot be played by ordinary computer players. Identification, this is to prevent user privacy leakage.

Extended information:

Common music formats:

1. WAV format

An audio format developed by Microsoft a long time ago that conforms to PIFF Resource Interchange File Format file specification. WAV has no hard and fast requirements for the encoding of audio streams. You can use a variety of audio encodings to compress its audio streams. However, what we commonly see are WAVs in which the audio streams are encoded by PCM, but this does not mean that WAV can only use PCM encoding or MP3 encoding. It can also be used in WAV. Like AVI, as long as the corresponding Decode is installed, you can enjoy these WAVs.

2. APE format

APE is a distortion-free compression format provided by Monkey's Audio. Monkey'sAudio provides Winamp plug-in support, so this means that the compressed file is no longer a simple compression format, but an audio file format that can be played like MP3.

The compression ratio of this format is much lower than other formats, and it can be truly lossless, so it has won the favor of many enthusiast users. Among the many existing distortion-free compression solutions, APE is a format with outstanding performance, satisfactory compression ratio and fast compression speed, which has become a choice for many friends to communicate privately about audiophile music.

3. MP3 format

The full name of MP3 format is Moving PictureExperts Group Audio Layer III. It has a history of 30 years and was born in Germany. MP3 refers to the audio compression method in the MPEG standard, referred to as MP3.

The compression of MPEG audio files is a kind of distortion compression, which compresses the music into smaller files with a compression ratio of 10:1 or even 12:1. It basically keeps the low-pitched sound part without distortion, but loses the quality of the high-pitched sound part from 12KHz to 16KHz in the sound file. Music files of the same length, stored in MP3 format, are generally only 1/10 of the wav file, and the sound quality is inferior. Audio files in CD format or WAV format.

Due to its small file size and good sound quality, there was no other audio format that could compete with it when it came out, thus providing good conditions for the development of the MP3 format.

4. WMA format

WMA is the file format encoded by Windows Media Audio. It was developed by Microsoft. The sound quality is better than MP3 format and far better than RA format. It and YAMAHA company The developed VQF format achieves a higher compression rate than MP3 while maintaining sound quality. The compression rate of WMA can generally reach about 1:18. WMA is not targeting the stand-alone market, but the network. The competitor is Real Networks, a well-known company in the online media market.

Microsoft claims that WMA can achieve sound quality close to CD at a bit rate of only 64kbps. Different from previous encodings, WMA supports anti-copying function, supports adding protection through Windows Media Rights Manager, and can limit playback time, playback times and even playback machines, etc.

5. ACC format

AAC (Advanced Audio Coding) is a technology provided by Dolby Labs for the music community. AAC claims to "can accommodate up to 48 channels of audio tracks, with a sampling rate of 96 KHz, and can provide 5.1-channel music programs with quality equivalent to ITU-R broadcasting at a data rate of 320Kbps."

Compared with MP3, its sound quality is better and it can save about 30% of storage space and bandwidth. It is a technology developed in compliance with MPEG-2 specifications.

6. FLAC format

FLAC is the abbreviation of Free Lossless AudioCodec, which can be interpreted as lossless audio compression coding in Chinese. FLAC is a well-known set of free audio compression codes, which is characterized by lossless compression. Unlike other distortion compression codes such as MP3 and AAC, it does not destroy any original audio information, so it can restore the sound quality of music CDs.

It is now supported by many software and hardware audio products. In short, FLAC is similar to MP3, but it is compressed without distortion, which means that the audio will not lose any information when compressed in FLAC.

This compression method is similar to Zip, but FLAC will give you a larger compression ratio because FLAC is a compression method specifically designed for the characteristics of audio.

Baidu Encyclopedia-Music Format

Baidu Encyclopedia-MP3