Media Streaming on RPi

 Project: Media Streaming on RPi Using miniDLNA 

This document deals with setting up the miniDLNA service on a Raspberry Pi to serve as DLNA media server.

Accelerated Installation
$ sudo apt-get install minidlna $ sudo chown minidlna:minidlna /var/lib/minidlna

Create log and cache files for MiniDLNA, edit the conf file and restart.

$ sudo mkdir /var/{cache,log}/minidlna $ sudo chown minidlna:minidlna /var/{cache,log}/minidlna

Edit the config file $ sudo nano /etc/minidlna.conf media_dir=V,/media/mediadir db_dir=/var/cache/minidlna log_dir=/var/log/minidlna inotify=yes notify_interval=895 listening_ip=[IP of rPi]

Add this to the end of the /etc/sysctl.conf file to fix some issues $ sudo nano /etc/sysctl.conf fs.inotify.max_user_watches = 100000
 * 1) minidlna server tweaks
 * 1) end of minidlna server tweaks

Give MiniDLNA permissions to view the media_dir if stored under another user/group permission. To do this, add the minidlna user to the mediastore group as my media_dir allows the mediastore group to make changes. $ sudo usermod -a -G mediastore minidlna Force-reload MiniDLNA $ sudo service minidlna stop $ sudo service minidlna start $ sudo service minidlna force-reload

Your Raspberry Pi will now be able to stream media over your network.

Normal Installation
From the command prompt type:

$ sudo apt-get install minidlna

Configuration
The MiniDLNA daemon can be run as either a global (config:/etc/minidlna.conf) or per-user instance (config:user-defined), these are the necessary common settings:

network_interface=eth0                     # Self-discovers if commented (at times necessary to set) media_dir=A,/home/user/Music               # Mounted Media_Collection drive directories media_dir=P,/home/user/Pictures            # Use A, P, and V to restrict media 'type' in directory media_dir=V,/home/user/Videos friendly_name=Media Server                 # Optional, but recommended db_dir=/var/cache/minidlna                 # MiniDLNA Media_DB dir needs to be un-commented log_dir=/var/log                           # Log dir needs to be un-commented inotify=yes                                # 'no' for less resources, restart required for new media presentation_url= http://www.mylan/index.php # or use your device static IP http://192.168.1.1:8200/

Global
MiniDLNA scans your Media_Collection at startup and creates or updates database Media_DB browsable via media players. Set database cache and logging dirs in config, so the db and album art cache will not be re-created on every restart. By default MiniDLNA runs as nobody user without shell access as set in /etc/conf.d/minidlna, unless you set your own. That user needs rw permissions to cache and log directories you specified in conf. Create the required directories and chown them to nobody:nobody. You can also specify a user to run as via the minidlna.conf file by setting


 * 1) user=jmaggard

Default cache and log directories need to be created and chowned to the chosen user.

$ sudo mkdir /var/{cache,log}/minidlna $ sudo chown nobody:nobody /var/{cache,log}/minidlna

If you change MiniDLNA user, you can login as that user and create a symbolic link in the default Media_DB directory to a mounted in the system external Media_Collection drive, just make sure to set the user's rw permissions and other mount options for the drive in fstab if present at boot, or udev automount rules if attached after boot:

$ sudo ln -s /media/MyDrive/Media_DB /var/cache/minidlna

Automatic Media_DB Update
Kernel adds one inotify watch per each folder/subfolder in Media_Collection Directories set in /etc/minidlna.conf to monitor changes thus allowing MiniDLNA to update Media_DB in real time. When MiniDLNA is run as a regular user, it does not have the ability to change the kernel's inotify limits. If default number of inotify watches is non-sufficient to have MiniDLNA monitor all your media folders, increase inotify watches through sysctl (100000 should be enough for most uses):

$ sudo sysctl fs.inotify.max_user_watches=100000

To have it permanently changed, add to /etc/sysctl.conf

fs.inotify.max_user_watches = 100000
 * 1) Increase inotify max watchs per user for local minidlna

inotify performance may depend on device type. Some do not rescan media drives on a consistent basis or at all. If files are added/deleted to monitored media directories, they may not be noticed until the device DLNA client is restarted.

Check inotify updates via MiniDLNA presentation_url by comparing files count. If it does not change, make sure the user running MiniDLNA has rw access to the DB folder. If the issue persists, copy or download new files first to a non-watched by inotify Downloads folder on the same drive, and then move them to appropriate media folders, since lengthy media files copying or downloading may confuse inotify.

You can also clean or rebuild MiniDLNA DB manually after stopping MiniDLNA daemon, or analyze its debug output (Ctrl+C to exit):

Stop the MiniDLNA daemon: $ sudo service stop minidlna

To rebuild Media_DB forcibly: $ sudo -u nobody minidlna -R or $ sudo service minidlna force-reload Stop the daemon after rebuilding Media_DB e.g. killall minidlna.

To run in debug mode: $ sudo -u nobody minidlna -d Ctrl+C to exit it.

Other aspects
Other aspects and MiniDLNA limitations may need to be considered beforehand to ensure satisfaction from its performance.

Firewall
If using a firewall the the ssdp (1900/udp) and trivnet1 (8200/tcp) ports will need to be opened. For example, this can be done with arno's iptables firewall by editing firewall.conf and opening the ports by doing:

OPEN_TCP="8200" OPEN_UDP="1900"

File System and Localization
When keeping MiniDLNA Media_DB on an external drive accessible in both Linux and Windows, choose proper file system for it. NTFS preserves in Windows its Linux defaults: rw access for root user and UTF8 font encoding for file names, so media titles in your language are readable when browsing Media_DB in terminal and media players, since most support UTF8. If you prefer Vfat (FAT32) for better USB drive compatibility with older players when hooked directly, or your Media_Collection drive is Vfat and has folder & file names in your local language, MiniDLNA can transcode them to UTF8 charset while scanning folders to Media_DB. Add to Media_Collection and Media_DB drives' mount options your FS language codepage for transcoding to short DOS file names, and iocharset for converting long file names to your terminal's locale, i.g. codepage=cp866,iocharset=utf8 (or ISO-8859-5). Set rw permissions for all users, since Vfat does not preserve Linux access permissions:

UUID=6140-75F7 /media/MyDrive/Media_DB vfat user,rw,async,noatime,umask=111,dmask=000,codepage=cp866,iocharset=utf8 0 0

While your iocharset would be present in the system with a matching locale, if your terminal or player supports only short file names, check if the set codepage is also present and enabled (like ru_RU.CP866), i.e. was included in system config when ArchLinux release was compiled, or consider recompiling the release to add it:

ls /usr/share/fonts/encodings

MiniDLNA lists Movies and Photos by file name in its DB, and Music entries by ID3 tags instead of file names. If Music collection was not tagged in UTF8 but in a local charset, MiniDLNA might not identify and transcode it correctly to UTF8 for display in media players, or the original tags codepage(s) may be absent in your system, so the tags will not be readable even when media file names are. In this case consider re-tagging your collection to UTF-16BE or UTF-8 encoding with an ID3 Tag Converter.

Picking the "right" file system for your Media_Collection is a trade-off: XFS and EXT4 show fast read/write for HDs and lower CPU load critical for small Plug Computers with attached storage. NTFS is most compatible with Windows when plugging a drive directly for faster copy, while network file systems like Samba, NFS or iSCSI allow import to Windows any Linux FS with slower data copy. As file fragmentation affects playback, store your Movies on a non-system drive formatted in XFS (prevents fragments), NTFS (fragment resistant and easy to defrag), or EXT4 (uses large file extents), and avoid EXT3 or less resistant FAT32. For smaller Flash drives with seldom fragmented Music and Photo files, VFAT (FAT32) and EXT4 show faster writes with less CPU load, but EXT4 may affect memory wear due to journaling, and less compatible with media players. Proper drive partitioning, block alignment and mount options (i.e. async,noatime...- choice depends on file system and memory type) can greatly accelerate flash and HD drive speed among other advantages.

Media Handling
MiniDLNA is aimed for small devices, so does not generate movie thumbnails to lower CPU load and DB built time. It uses either thumbs in the same folder with movie if any, or extracts them where present from media containers like MP4 or MKV with embedded Album Art tags, but not AVI. One can add thumbs (JPG 160x160 pxl or less) to media folders with a Thumbnail Maker, and miniDLNA will link them to media files after rescan. Larger thumbs will be resized and stored in Media_DB that slows scan. At one movie per folder, follow thumb naming rules in minidlna.conf. For multiple show episodes per folder, each thumb name should match its episode name without ext. ( .cover.jpg or  .jpg). To handle MS Album Art thumb names with GUID, add * to the end "AlbumArt_{*".jpg. MiniDLNA will list on screen only chosen media type (i.e. Movies), but will not other files in the same folder.

When viewing photos, progressive and/or lossless compression JPG may not be supported by your player via DLNA. Also resize photos to "suggested photo size" by the player's docs for problem free image slideshow. DLNA spec restricts image type to JPG or PNG, and max size to 4096 x 4096 pixels - and that is if the DLNA server implementation supports the LARGE format. The next size limit down (MEDIUM) is 1024 x 768, so resizing may help to show photos correctly.

To decrease system load, MiniDLNA does not transcode on the fly unsupported media files into supported by your player formats. When building Media_DB, it might not correctly identify whether certain formats are supported by your player, which may play via UPnP a broader formats choice. DLNA standard is quite limiting UPnP subset in media containers and codec profiles allowed. If you do not see on TV screen or cannot play some media files listed in Media_DB, check if your HD started spinning or try connecting to your media player via USB for their playback. MiniDLNA might not support choosing audio tracks, subtitles, disk chapters, list sorting, and other advanced playback features for your player model.

Building a media server
Media served could be based on lightweight and cheap system like development board (Raspberry Pi, CubeBoard, etc.). You do not even need to put X Server on this board.

Automount external drives
This is very useful if you want to automate the server. See http://elinux.org/RPi_Adding_USB_Drives for more information.

Issues
Media server based on MiniDLNA could face the drive re-scan issue. Ex.: external HDD you have plugged will be scanned each time again and again. This happens due to MiniDLNA removes DB records for unplugged drive. If your drive plugged all the time it is not a problem, but if you have "pluggable" media library on large external drives this could take a big while till you start watching your video.

As solution for rescan issue could be used minidlna fork. It creates metadata file next to each video file. That significantly increase scan time for large media.

Server not visible on Wireless behind a router
On some network configurations when the machine hosting MiniDLNA server is connected to the router through Ethernet, there may be problems accessing MiniDLNA server on WiFi (same router).

To solve this, make sure that "Multicast Isolation" is turned off on the router.

Set a very high notify_interval
There are 2 possible fixes for this problem. The first is to set your notify_interval level in the /etc/minidlna.conf file to a very high number, such as 90000. This solves the issue but since the notify interval was so high MiniDLNA will not search the media_dir for new files for a long time.

Disable UPnP on the network router
The other fix is to turn off UPnP on your router. When turned off the issue never normally comes back, also set notify_interval to 895 and there shouldn't be anymore problems.

MiniDLNA doesn’t update files.db with new files that have been added to the media_dir
By changing the path of media_dir and creating a link to where my files are. By the following steps:Stop the minidlna service and delete the art_cache and files.db file $ sudo service minidlna stop $ sudo rm -r /var/cache/minidlna/* Edit minidlna.conf with the path to the new media_dir $ sudo nano /etc/minidlna.conf media_dir=V,/var/lib/minidlna/videos

create a link in /var/lib/minidlna to your media location $ sudo ln -s /media/mediadir /var/lib/minidlna/videos Start MiniDLNA and give it time to recreate its DB $ sudo service minidlna force-reload

MiniDLNA doesn’t have permissions to view newly created folders in the watched media_dir
This can be solved by running MiniDLNA as the user root instead of minidlna. Edit init.d and add USER=root near the top. $ sudo nano /etc/init.d/minidlna USER=root