Using I2S audio and an Arduino for the remaining processing has several advantages, not the least of which is there is no additional wires for power and ground. I2S-USB is a formal specification released in April 2011 that provides the I2S audio interface in a USB port. The I2S serial bus runs at up to 2.5Mb/s and is used for the professional audio market. Not only is I2S-USB a standard on the desktop, it is also emerging in other platforms such as ARM Cortex-M processors.
If the VLC still play without video the problem can be due to the incompatible video codec contained in the files. In this case, maybe need to convert the file to VLC more supported video format. You can choose Makemkv or Pavtube video converter,both powerful video tools.
The final approach is to add an advanced audio IC with an internal microcontroler with firmware such as an MP3/WAV player chip. Recently, some very low cost MP3 player modules have been introduced. They have been used in Arduino projects so they are widely available from several sources and have even been cloned with a few different parts on the module.The DFPlayer mini modules are available for under $3 from some places like Amazon or Alibaba. It plays the common sound file formats including MP3 at up to 44Khz with a 24bit DAC and even contains a 3W driver for a speaker with stereo outputs for headphones. They have a uSD card slot on the board for music files or it can read a USB flash drive. Audio file names will require a three digit numeric prefix, 00x*.*. There are also a bit larger versions of the module with a headphone jack, but no audio amp. It needs a serial port for control running at 9600 baud or pushbuttons. There is an mbed driver library available at: and there is a datasheet available and there is another more complete datasheet. As seen in the image above, the DFPlayer module contains a small audio amp IC (left) and an YX5200-24SS MP3 chip(right). d2c66b5586