What is a codec?

A codec is a hardware or software-based process that compresses and decompresses large amounts of data. The function of codecs is for applications to play and create multimedia files for users. Other functions are to send multimedia files by streaming. The term is a combination of the words coder and decoder.

Codecs compress, or shrink, multimedia files such as videos, audios and still images. In this way, they aim to save space on devices and efficiently send those files over a network faster.

Codecs are invisible to the user. In fact, they are present in the software or hardware of a device. That is, there is software that acts as a codec. To do so, they use the CPU for encoding and decoding. There are also accelerators running in hardware. That is, they use a specific processing unit to accelerate encoding and decoding. The latter is the case of AV-1 engines implemented in current graphics cards.

The main function of a codec is data transformation and encapsulation. We can have audio, image or video codecs. Video codecs usually include both image and sound codecs at the same time. In fact, video is nothing more than a series of frames passing through.

Codecs use an algorithm to convert data into a sequence of bytes different from the original. In this way, they achieve their purpose, which is to reduce the file size or space occupied.

The higher the bit rate, the lower the compression. And lower compression generally means higher quality, or closer to the original, in general. Some codecs create smaller files with reasonably acceptable quality. Other codecs create efficient files that have higher quality but take up more space. Other codecs create small, efficient files, but lack overall quality.

What is coding?

Encoding is a process used to compress multimedia data, such as videos, audios, and images. This in order to reduce the size of the files. In addition to facilitating their transmission and storage. This is done at the moment of recording or creating the media file in question, or after editing it. Encoding is possible in two ways:

• Lossy compression: Is a method of data compression in which some redundant or less important information is removed to reduce the file size. By removing data, there is a loss of quality in the original content. It is widely used in multimedia data compression. For example, such as audio and video. In fact, there, the loss of certain details is not relevant to the human ear or eye.
• Lossless compression: Data compression: is a method of data compression that reduces the file size without losing information or quality of the original content. In this case, we could recover all the information deleted in the compression process. It is enough to decompress the file. Consequently, data loss is a real possibility.

Steps to perform coding

• Content analysis: First, the codec analyzes the multimedia content. Whether it is audio, video, or images. In this way, it seeks to identify relevant patterns and characteristics. This helps the codec determine which parts of the content can be compressed most effectively.
• Transformation: In this phase, the multimedia data is mutated to a more efficient mathematical representation. For example, in the case of video, there are transformation techniques such as the discrete cosine transform (DCT). In this way, they will represent the pixels in a more compact way.
• Quantization: In this step, the numerical values resulting from the transformation are quantized or rounded to discrete values. Quantization is a key technique for lossy compression. Indeed, it allows eliminating less important details and to reduce the precision of certain values.
• Compression: This is where data compression is actually achieved. The codec uses different techniques. For example, delta coding, Huffman coding or arithmetic coding. In doing so, it aims to represent the quantized data more efficiently. During this process, redundant or irrelevant data is removed or represented in a more compact form.
• Packaging: once the media data has been compressed, it is packaged in a container format. The container will include the compressed information along with metadata. In addition to other related information, such as audio tracks or subtitles.

What is decoding?

Decoding is the reverse process of encoding. That is, the procedure by which a set of encoded or compressed data is restored to its original form. In doing so, we restore the information and structure prior to encoding.

When applying some type of encoding or compression to data, the objective is to reduce its size. This makes it easier to store, transmit or process. However, to use this data again, it is necessary to perform the decoding process to recover the original information.

Steps for decoding

The decoding process is the opposite of the encoding process. Therefore, the steps would be:

• Receiving and opening the file: begins when the compressed and packaged media file arrives. The media player or the appropriate application opens the file to start the decoding process.
• Data extraction: the application extracts the compressed information from the archive. This information includes the compressed media data along with metadata. In addition to other relevant information stored in the container.
• Decompression: the application uses the appropriate codec to decompress them.The file may be lossy. Consequently, decompression will involve restoring the data to its original form. However, we may lose quality compared to the original uncompressed file.
• Inversion of quantization: if the encoding process included quantization, decoding must perform the reverse process. That is, restore the quantized values to their original values.
• Inverse transformation: It is likely to have used some mathematical transformation in the coding process. Then, the decoding must perform the inverse transformation to return to the original representation of the data.
• Data reconstruction : After decompressing and transforming the data to its original form, the application can reconstruct the multimedia data. For example, in the case of video, we can restore the frames and image sequence to play the original video.
• Playback or display: Finally, the multimedia data is output to the output device, such as a display or speaker. In this way, the user can watch or listen to the multimedia content in its original form.

What is transcoding?

Transcoding is the process of converting a media file from one encoding format to another encoding format. In this process, we extract the information present in the original file and recode it into a new format. This involves a conversion of the data to suit the characteristics and requirements of the target format.

Transcoding is only available between some types of codecs or formats. Indeed, it is not possible, for example, to transcode or convert a text to use an audio codec. It is possible to convert from audio to audio, from video to video, from image to image, etc.

Difference between container format and codec

It is important to know the differences between codec and container. Indeed, it is something that many users often confuse:

• Codec: is an algorithm or set of algorithms whose function is to compress and decompress multimedia data. For example, audio, video, or images. Codecs are responsible for encoding the original information into a more compact format for storage or transmission. In addition, they then decode it again for playback or display. There are both lossy and lossless codecs. Therefore, it means that some compress the data by removing some information (lossy). On the other hand, others compress without losing information (lossless). Examples of common codecs are H.264, AAC, MP3, VP9, among others.
• Container: Also known as a file format. It is a structure that stores multimedia data compressed with a codec along with additional information. For example, metadata, subtitles, and audio or video tracks. With containers, we can group all these elements in a single file. This facilitates the handling, storage and transmission of multimedia files. Containers do not directly affect the quality of the content. In fact, they simply organize and store the compressed data with codecs. Examples of popular containers are MP4, MKV, AVI, MOV and FLAC.

The post Multimedia Codec: How to compress videos, images, and audio! appeared first on Linux Windows and android Tutorials.

Introducing to Jellyfin

Jellyfin is the volunteer-built media solution that puts you in control of your media. Stream to any device from your own server, with no strings attached. Your media, your server, your way.

The app enables you to collect, manage, and stream your media. Run the Jellyfin server on your system and gain access to the leading free-software entertainment system, bells and whistles included.

So if you have a lot of media files and you want to have them always at hand, then Jellyfin is the best for you.

Install Jellyfin on Ubuntu 20.04

Installing Jellyfin is possible thanks to a repository that we have to add to do the process. So, let’s get started.

First, open a terminal and upgrade Ubuntu

sudo apt update
sudo apt upgrade

After that, you need to enable the Ubuntu universe repository. This is because Jellyfin requires dependencies to be loosened in that repository.

sudo add-apt-repository universe

Then install a package called apt-transport-https that will help add the Jellyfin repository.

sudo apt install apt-transport-https

After that, you can download and add the GPG key from the official repository of the application

wget -O - https://repo.jellyfin.org/ubuntu/jellyfin_team.gpg.key | sudo apt-key add -
--2021-03-06 17:13:36--  https://repo.jellyfin.org/ubuntu/jellyfin_team.gpg.key
Resolving repo.jellyfin.org (repo.jellyfin.org)... 2604:a880:cad:d0::cf3:f001, 68.183.204.194
Connecting to repo.jellyfin.org (repo.jellyfin.org)|2604:a880:cad:d0::cf3:f001|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3078 (3.0K) [application/octet-stream]
Saving to: ‘STDOUT’

-                                          100%[=====================================================================================>]   3.01K  --.-KB/s    in 0s      

2021-03-06 17:13:36 (127 MB/s) - written to stdout [3078/3078]

OK

This process ensures that we can install applications from the repository. Making the system more and more secure.

Now yes, add the Jellyfin repository.

echo "deb [arch=$( dpkg --print-architecture )] https://repo.jellyfin.org/ubuntu $( lsb_release -c -s ) main" | sudo tee /etc/apt/sources.list.d/jellyfin.list

deb [arch=amd64] https://repo.jellyfin.org/ubuntu focal main

And refresh APT so that the process can complete.

sudo apt update

Now you can install the application by running

sudo apt install jellyfin
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  fontconfig-config fonts-dejavu-core jellyfin-ffmpeg jellyfin-server jellyfin-web libass9 libbluray2 libcairo2 libdrm-intel1 libfontconfig1 libgraphite2-3
  libharfbuzz0b libmp3lame0 libopus0 libpciaccess0 libpixman-1-0 libtheora0 libvdpau1 libvorbisenc2 libvpx6 libwebp6 libwebpmux3 libx11-6 libx11-data libx264-155
  libx265-179 libxau6 libxcb-render0 libxcb-shm0 libxcb1 libxdmcp6 libxext6 libxrender1 libzvbi-common libzvbi0 ocl-icd-libopencl1
Suggested packages:
  libbluray-bdj opus-tools opencl-icd
Recommended packages:
  libaacs0 vdpau-driver-all | vdpau-driver
The following NEW packages will be installed:
  fontconfig-config fonts-dejavu-core jellyfin jellyfin-ffmpeg jellyfin-server jellyfin-web libass9 libbluray2 libcairo2 libdrm-intel1 libfontconfig1 libgraphite2-3
  libharfbuzz0b libmp3lame0 libopus0 libpciaccess0 libpixman-1-0 libtheora0 libvdpau1 libvorbisenc2 libvpx6 libwebp6 libwebpmux3 libx11-6 libx11-data libx264-155
  libx265-179 libxau6 libxcb-render0 libxcb-shm0 libxcb1 libxdmcp6 libxext6 libxrender1 libzvbi-common libzvbi0 ocl-icd-libopencl1
0 upgraded, 37 newly installed, 0 to remove and 20 not upgraded.
Need to get 93.4 MB of archives.
After this operation, 291 MB of additional disk space will be used.

After installing, you need to start it and enable it so it can start with the system.

sudo systemctl enable --now jellyfin
Synchronizing state of jellyfin.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable jellyfin

To check that everything is OK, check the status of the service

sudo systemctl status jellyfin
● jellyfin.service - Jellyfin Media Server
     Loaded: loaded (/lib/systemd/system/jellyfin.service; enabled; vendor preset: enabled)
    Drop-In: /etc/systemd/system/jellyfin.service.d
             └─jellyfin.service.conf
     Active: active (running) since Sat 2021-03-06 17:15:35 CET; 2min 3s ago
   Main PID: 3764 (jellyfin)
      Tasks: 16 (limit: 2286)
     Memory: 89.9M
     CGroup: /system.slice/jellyfin.service
             └─3764 /usr/bin/jellyfin --webdir=/usr/share/jellyfin/web --restartpath=/usr/lib/jellyfin/restart.sh --ffmpeg=/usr/lib/jellyfin-ffmpeg/ffmpeg

Mar 06 17:15:43 osradar jellyfin[3764]: [17:15:43] [INF] Registering publisher for urn:schemas-upnp-org:device:MediaServer:1 on 157.90.172.109
Mar 06 17:15:43 osradar jellyfin[3764]: [17:15:43] [INF] Executed all pre-startup entry points in 0:00:00.8272122
Mar 06 17:15:43 osradar jellyfin[3764]: [17:15:43] [INF] Core startup complete
Mar 06 17:15:44 osradar jellyfin[3764]: [17:15:44] [INF] Executed all post-startup entry points in 0:00:00.5657009
Mar 06 17:15:44 osradar jellyfin[3764]: [17:15:44] [INF] Startup complete 0:00:08.0004279
Mar 06 17:15:45 osradar jellyfin[3764]: [17:15:45] [INF] StartupTrigger fired for task: Update Plugins
Mar 06 17:15:45 osradar jellyfin[3764]: [17:15:45] [INF] Queueing task PluginUpdateTask
Mar 06 17:15:45 osradar jellyfin[3764]: [17:15:45] [INF] Executing Update Plugins
Mar 06 17:15:46 osradar jellyfin[3764]: [17:15:46] [INF] Update Plugins Completed after 0 minute(s) and 0 seconds
Mar 06 17:15:46 osradar jellyfin[3764]: [17:15:46] [INF] ExecuteQueuedTasks

Jellyfin is now available on http://server:8096 but you should set up a reverse proxy with Nginx and enable HTTPS to ensure that all data transmitted is secure.

Configuring Nginx as the reverse proxy and enabling HTTPS

So, install Nginx and make sure it is running.

sudo apt install nginx
sudo systemctl status nginx

Then create a new configuration file for Jellyfin

sudo nano /etc/nginx/conf.d/jellyfin.conf

And add the following content

upstream backend {
     server 127.0.0.1:8096;
     keepalive 64;
 }

 server {
    listen 80;
    server_name osradartest.ga;

 location / { 
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Server $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_pass_request_headers on;
        proxy_set_header Connection "keep-alive";
        proxy_store off;
 }
 }

Save the changes and close the editor.

After that, you need to enable HTTPS and with the help of Certbot the process is very easy. So, install it as well as the Nginx plugin.

sudo apt install certbot python3-certbot-nginx

After that, get a new certificate with the following command:

sudo certbot --nginx --agree-tos --redirect --hsts --staple-ocsp --email you@example.com -d your-domain

Of course, replace the value of --email and -d with your email and domain respectively.

Finally, restart Nginx.

sudo systemctl restart nginx

And you will be able to access Jellyfin to complete the installation.

Complete the installation of Jellyfin on Ubuntu

Now open a web browser and go to https://your-domain and you will see the loading screen.

Then you will see the welcome screen. Select the language to display and press the Next button.

Then, create a new user.

You can add your media collection at once.

After that, select the language of the metadata.

Then, you have the option to configure remote access.

If all goes well, you will see this screen.

Then log in with the user you created.

You will be able to enjoy Jellyfin and use your media library.

Conclusion

Jellyfin is another complete alternative to have our files in the cloud. In this case, they are multimedia files that we can play from anywhere with internet access.

The post Deploy your own multimedia center by installing Jellyfin on Ubuntu 20.04 appeared first on Linux Windows and android Tutorials.

FFmpeg  is a suite of open source software in command line that permits managing of audio or video streams. With it, you can make recordings, corrections with filters, or transcode media from one format to an other.

To perform this tutorial successfully, you need first of all, a user with super user privileges, then you must have knowledge about repositories and command line.

Let’s start with Debian 8

In case you have installed Debian 8 Jessie, you should know that FFmpeg is not available from the official Debian repositories, but you have to use the Debian Multimedia repository and install from there.

Adding the deb-multimedia repository

First ,you must edit the file /etc/apt/sources.list. In that file are the repositories that APT uses. Run, on a terminal:

:~$ sudo -i
:~# nano /etc/apt/sources.list

Now add the following lines to that file. It should look like this:

deb http://www.deb-multimedia.org jessie main non-free
deb-src http://www.deb-multimedia.org jessie main non-free

# jessie-backports
deb http://ftp.debian.org/debian/ jessie-backports main

The next step will be to install the deb-multimedia-keyring package to add the GPG keys from the repository. Run:

:~# apt update
:~# apt install deb-multimedia-keyring
:~# apt update

And finally we proceed to install FFmpeg.

:~# apt install ffmpeg

Now, Debian 9

If we have installed debian 9 in our computer and we want to install FFmpeg, then it is simple because in this version of Debian, it is inside the official repositories, for it is enough with one:

:~# apt install ffmpeg

And now we proceed to verify the installation:

:~# ffmpeg -version

Using FFmpeg. First steps.

First you must understand that FFmpeg runs mainly from the command line interface, i.e. you have to use the terminal. We know that not everyone is comfortable with that, but it’s not difficult. To help with the compression of the tool, we will explain it with some examples:

• Displaying usage information on the terminal

To learn how to use a tool, nothing like keeping an eye on official information, for it, write:

:~# ffmpeg --help

Executing the above command, you will get information about how to use it and its multiple configuration options.

• Get the information about a video file

Many times you need to know the information of a video, for it, runs on a terminal:

:~# ffmpeg -i file.flv

The result will be something like this:

• Convert a video to another format

It is one of the basic tasks in today’s multimedia work. FFmpeg has many and varied conversion options, believe me, they are many but in a more elementary way, it can be done by running:

:~# ffmpeg -i inputvideo.x output.x

Note: .x is pointed out to clarify that the format is variable (mp4, 3gp, mpg, mkv..etc) in both input and output video.

Although it is known that when converting a video to another format, it is possible to lose quality, it is possible to tell FFmpeg to try to have the same quality by adding the -sameq (same quality) option.

:~# ffmpeg -i inputvideo.x -sameq output.x

• Mixing an audio file and a video

Imagine that you have a video presentation and you want to put an audio, well it is possible to do it with this command:

:~# ffmpeg -i audio.mp3 -i video.avi video_and_audio.mpg

So far we have seen a few but illustrative examples, however the possibilities are almost limitless.

Bonus: QwinFF a FFmpeg GUI (Debian 9)

Because FFmpeg is a very powerful tool, its possibilities are very wide and not many people are comfortable using the command line interface, so here’s QwinFF.

QwinFF is an open source aplicaciṕn built with C++ and QT4 that aims to simplify the use of FFmpeg by providing a clean and concise graphical interface. Let’s install it. Run:

:~# wget https://launchpad.net/~lzh9102/+archive/ubuntu/qwinff/+files/qwinff_0.2.0-1~wily2_amd64.deb

Once the download is complete, we proceed to install the package dependencies:

:~# apt install libqt4-dbus libqtdbus4 qdbus qtcore4-l10n libdirectfb-1.2-9 libvorbisidec1 libsox-fmt-alsa libsox-fmt-ao libsox-fmt-oss libsox-fmt-pulse libsox-fmt-base libsox2 libqt4-network libqt4-opengl libqtcore4 libqtgui4 sox mplayer qtchooser libqt4-xml libqt4-xml

Next:

:~# dpkg -i qwinff_0.2.0-1~wily2_amd64.deb

Now run it:

And that’s it, with this we have finished installing QwinFF. Now we have to discover and use their options.

I hope you liked this article that serves as an introduction to this great tool like FFmpeg. Leave us your comment telling us about your experience.

Please spread this article through your social networks.

The post Installing and using FFmpeg on Debian 8 and Debian 9? appeared first on Linux Windows and android Tutorials.