ffmpeg

How to Create a WiFi Hotspot in Ubuntu 22.04

 in GNU/Linux  tagged ffmpeg / GNU/Linux / hotspot / nmcli / ubuntu / wi-fi by

Creating a WiFi hotspot on Ubuntu 22.04 is a straightforward process that can be very useful for sharing your internet connection with other devices. Turning your Ubuntu machine into a WiFi access point is a handy solution, whether at home or in a setting where a traditional WiFi network isn’t available. Here’s a detailed guide on configuring WiFi Access Points using the network-manager snap.

Prerequisites

Before we begin, ensure that you have the following:

  • A computer running Ubuntu 22.04.
  • A wireless network interface on your Ubuntu device.
  • The network-manager snap installed on your system.

Step-by-Step Guide to Create a WiFi Hotspot

Open the Terminal: First, open your terminal. You can do this by pressing Ctrl + Alt + T or searching for ‘Terminal’ in your applications menu.

Identify Your WiFi Interface: You need to know the name of your WiFi network interface. You can find this by running the command nmcli device status. Look for the device under the “DEVICE” column that has “wifi” listed in the “TYPE” column.

Configure the WiFi Hotspot: Use the following command to set up your WiFi hotspot:php

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nmcli d wifi hotspot ifname <wifi_iface> ssid <ssid> password <password>;

Replace <wifi_iface> with your WiFi interface name, <ssid> with your desired network name (SSID) and <password> with your chosen password. Remember, the password should be between 8-63 characters or 64 hexadecimal characters.

For example, if your WiFi interface is wlan0, your desired SSID is MyHotspot, and your password is MyStrongPassword123, the command will look like this:

Connection Verification: If the command is successful, network-manager will create a connection named ‘Hotspot <N>’, where <N> is a number. This indicates your hotspot is active.

Shared Internet Connection: The created hotspot offers a shared connection by default. This means any device connected to your hotspot should be able to access the internet if your Ubuntu device has internet access.

Connecting Devices: Search for available WiFi networks on your other devices (like smartphones or laptops). You should see the SSID you set (MyHotspot in our example). Connect to it using the password you configured.

Tips and Considerations

  • Ensure your device has a stable internet connection if you intend to share it via the hotspot.
  • Keep your hotspot secure by using a strong, unique password.
  • Remember that using your computer as a hotspot may impact its battery life more quickly if not plugged in.

Conclusion

Creating a WiFi hotspot on Ubuntu 22.04 is a useful feature, especially when you need to share your internet connection quickly and efficiently. Following these simple steps, you can turn your Ubuntu machine into a reliable WiFi access point for various devices.

ncmli device wifi hotspot [ifname ifname] [con-name name] [ssid SSID] [band {a | bg}] [channel channel] [password password]
   Create a Wi-Fi hotspot. The command creates a hotspot connection profile according to Wi-Fi device capabilities and activates it on the device. The hotspot is secured with WPA if device/driver supports that, otherwise WEP is used. Use connection down or device down to stop the hotspot.

   Parameters of the hotspot can be influenced by the optional parameters:

   ifname
       what Wi-Fi device is used.

   con-name
       name of the created hotspot connection profile.

   ssid
       SSID of the hotspot.

   band
       Wi-Fi band to use.

   channel
       Wi-Fi channel to use.

   password
       password to use for the created hotspot. If not provided, nmcli will generate a password. The password is either WPA pre-shared key or WEP key.

       Note that --show-secrets global option can be used to print the hotspot password.
       It is useful especially when the password was generated.

ffmpeg to convert MP4 files to MKV files with the libx265 video codec

 in Bash / GNU/Linux  tagged analyzeduration / bash color / color / ffmpeg / libx265 / mp4 / probesize by

When working with video files, there are times when you need to convert them from one format to another or modify them in some other way. One of the most popular tools for this is ffmpeg. This command-line tool can do a lot of things related to video processing, including conversion, resizing, cropping, and more. In this blog post, we will explain a script that uses ffmpeg to convert MP4 files to MKV files with the libx265 video codec.

The Script:

Here’s the script that we will be explaining:

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for FILE in *.mp4; do
  echo -e "Processing video '\e[32m$FILE\e[0m'";
  ffmpeg -i "${FILE}" -analyzeduration 2147483647 -probesize 2147483647 -c:v libx265 -an -x265-params crf=0 "${FILE%.mp4}.mkv";
done;

Let’s break this script down line by line to understand what it does.

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for FILE in *.mp4; do
...
done;

This line starts a loop that goes through all the files in the current directory that have the “.mp4” extension. The loop will execute the commands inside the “do” and “done” keywords for each file that matches this pattern.

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echo -e "Processing video '\e[32m$FILE\e[0m'";

This line uses the “echo” command to print a message to the console. The message includes the file’s name being processed, which is stored in the $FILE variable. The “\e[32m” and “\e[0m” are escape sequences that change the color of the text to green. This is just a way to make the message more visually appealing.

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ffmpeg -i "${FILE}" -analyzeduration 2147483647 -probesize 2147483647 -c:v libx265 -an -x265-params crf=0 "${FILE%.mp4}.mkv";

This line runs the ffmpeg command to convert the current file from MP4 to MKV format using the libx265 video codec. Let’s break down each of the options:

  • “-i ${FILE}” specifies the input file. “${FILE}” is the name of the file being processed, which is stored in the $FILE variable.
  • “-analyzeduration 2147483647” and “-probesize 2147483647” are options that tell ffmpeg to analyze the entire file before starting the conversion process. This can help avoid some issues that can occur when processing large files.
  • “-c:v libx265” specifies the video codec for the output file. libx265 is a popular video codec that provides good quality at a smaller file size.
  • “-an” specifies that there should be no audio in the output file.
  • “-x265-params crf=0” sets the quality level for the video. A value of 0 means lossless compression, which is the highest quality possible.
  • “${FILE%.mp4}.mkv” specifies the name of the output file. “${FILE%.mp4}” removes the “.mp4” extension from the input file name, and “.mkv” adds the “.mkv” extension to the end.

Conclusion:

The script we’ve just explained is a simple example of how you can use ffmpeg to convert MP4 files to MKV files with the libx265 video codec. It uses a loop to process all the files in the current directory that match the “.mp4” pattern. The script also prints a message to the console for each file

Compiling ffmpeg with NVIDIA GPU Hardware Acceleration on Ubuntu 20.04LTS

 in Applications  tagged cuda / ffmpeg / GPU / nvidia / ubuntu by

Please note that the following commands were executed on a system that already had CUDA support so we might be missing a step or two to enable NVIDIA CUDA support.

Install necessary packages

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sudo apt-get install build-essential yasm cmake libtool libc6 libc6-dev unzip wget libnuma1 libnuma-dev nvidia-cuda-toolkit;

Clone and install ffnvcodec

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git clone https://git.videolan.org/git/ffmpeg/nv-codec-headers.git;
cd nv-codec-headers;
sudo make install;
cd -;

Clone and compile FFmpeg’s public GIT repository with NVIDIA GPU hardware acceleration

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git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg/;
cd ffmpeg;
./configure --enable-nonfree --enable-cuda-nvcc --enable-libnpp --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib64 --disable-static --enable-shared;
make -j 8;
sudo make install;

SUCCESS!

After performing the above steps, we were able to process media using ffmpeg without stressing our CPU! The workload was transferred to the GPU!

FFmpeg tiny cheat sheet

 in Applications  tagged audio / concat / copy / export / ffmpeg / ffprobe / fps / frame rate / frames / hstack / libmp3lame / libx264 / merge by

We assume that the user has set the video filename to the variable named $video in the following commands.

FFmpeg export audio from any video to mp3

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ffmpeg -i "$video" -vn -c:a libmp3lame -y "$audio";

FFmpeg export frames from video to images

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ffmpeg -i "$video" "$frames_folder/%08d.ppm";

Retrieve the frame rate from the input video

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#To view it on screen
ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate "$video";
#To assign it to a variable use the following
frame_rate=`ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate "$video"`;

To create a video out of a folder with frames/images and an audio file.

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ffmpeg -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -pix_fmt yuv420p -acodec copy -y "$output_video";
#To set a custom starting index for the frames you can use the -start_number argument
ffmpeg -start_number 62 -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -pix_fmt yuv420p -acodec copy -y "$output_video";
#To use the MP4 coded use -vcodec libx264
ffmpeg -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -vcodec libx264 -pix_fmt yuv420p -acodec copy -y "$output_video";

To merge an audio less video with an audio file

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ffmpeg -i "$no_audio_video" -i "$audio" -shortest -vcodec copy -acodec copy "$output_video";

To change the frame rate of a video

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ffmpeg -i "$video" -filter:v fps=20 "$output_video";

To merge two videos side by side

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ffmpeg -i "$left_video" -i "$right_video" -filter_complex hstack "$output_video";

Concatenate multiple videos into one

The easiest way without writing huge commands is the following: First, create a file named parts.txt and add content similar to what we list below:

#Lines starting with # will be ignored
file 'part00-03.mp4'
file 'part04.mp4'
file 'part05-07.mp4'
file 'part08-09.mp4'
file 'part10.mp4'
file 'part11-13.mp4'

Then execute the following command to concatenate all those videos into one:

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ffmpeg -f concat -safe 0 -i parts.txt -c copy "$output_video";

Speed up a video

Using the following command, you can speed up a video by dropping excess frames:

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ffmpeg -i "$video" -filter:v "setpts=0.5*PTS" "$output_video";

The above example will double the speed (the value 0.5 controls it.)

To speed the video up without losing frames, you can increase the FPS value of the output video. To retrieve the frame rate, please see the command that was posted earlier.

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ffmpeg -i "$video" -r 80 -filter:v "setpts=0.25*PTS" "$output_video";

In the second example, we assumed that the input video had 20 frames per second. Using the 0.25 value, we decided to speed the video up by a factor of 4. To preserve the input frames, we increased the frame rate from 20 to 80 using the parameter -r.