Month: August 2017

Would you want to wait 10 minutes for the player to be ready before playing a file ?

Well the answer is NO.

When a disk is inserted in to most players , they start indexing. A process where they go thru each and every file in each and every folder and read the ID3 tags in them like album artist genre etc. This is time consuming and prevents the users from playing music right after inserting the disk. If a player tries to do this in the background it will interfere with the player trying to read the disk to play the file. You will have two processes contending for the disk access, the player to play the file, the Indexer which is making the disk read each and every file. The caching mechanism in the OS is useless for the indexer since it reads one file only once so the OS needs to keep dumping its cache. This is the reason you will see the Drives continually run during the indexing process.

We made a clear decision not to index the tags for USB disks, so when you insert the disk you can play files on them instantly. Only once process access the disk and that is the player. We assume most disks users insert will already have well organized folders that they are familiar with. We would still display the tags when the song is played, just not when the disk is inserted. This saves so much time and  frustration when playing files from the USB disks.

We are in the process of shortlisting the DACs and SBCs (Single Board Computer). Our initial design requirements looks like this.

A 32 bit 384KHz DAC , If the DAC is designed to play 34 bit 384KHz music really well, it will be awesome at playing 44.1/48Khz . Which is most of our music anyway.

Fully isolated power supplies for the SBC and the DAC. We would be using Linear supplies for both and a shield will separate the DAC and SBC boards to avoid EMI from the SBC corrupting the signals on the DAC.

We would be using the highest audio grade passive components in the analog section.

The SBC would use a Quad Core Processor with one core dedicated for the player by making it run at RT priority. At-least 1 GB of RAM.

The design would move the UI management to a separate Processor to keep the SBC free to only play the media, buffer etc. Most media player software available now tend to over load the main CPU with UI driving tasks, making it more prone skipping lockups etc.

To avoid IO bottlenecks, The player would move the files from the USB / Server to Ram-disk before playing so network / USB bottlenecks do not affect the playback.  It will also buffer other songs in the playlist in the background to avoid skips and delays.

The USB drive would support Drives up to 4TB with GPT and filesystems like FAT , FAT32, NTFS , EXT2, EXT3, EXT4.