How-To: January 2008 Archives

After my previous overview of Open Movie Editor (OME), I decided to create a small How-To regarding an easily obtainable piece of functionality that's not yet standard within OME.

Open Movie Editor natively contains only one transition between clips - a simple cross fade. However, one of the most used transitions in video editing is a fade to black. By adding a black still image, between two clips on a single video track in OME, it is possible to generate exactly what you need.

Here's how by following the steps below:

1. Open your favourite image editor, in this example we've used the GIMP.
2. Create a new image with a solid black background, at the same size as your video clips. We've used PAL 720x576.
3. Save the image as a PNG, although JPG will also work.
4. Switch to Open Movie Editor and navigate to your footage in the Media Browser window. We've previously downloaded two QuickTime clips from stock footage supplier BBC Motion Gallery, to use in this example.
5. Add the first clip to video track one.
6. Add the black still image to the same video track.
7. Add the second video clip to the same video track.
8. Now, overlap the beginning of the black still image with the end of the first clip. A blue area with a red cross through it should appear - this is the length of time that the fade will occur.
9. Adjust the length of the black still image to suit the speed of the fade to black required.
10. Now, drag the beginning of the second video clip over the end of the still image, so that another blue box and red cross appears.
11. Move the timeline marker before the first blue box and test your fade out to and in from black.

Easy! Move the clips, and adjust the length of the black still image until you are happy with the fade.

To make is even easier, we've created a screen cast for you to watch, complete with a couple of extra fades created in OME. Don't adjust your volume, there is no sound.

Get Flash Player 9 to see this movie.


This screen cast was created with RecordMyDesktop, edited with Open Movie Editor, and transcoded into an x264 file, using a custom Perl script to control FFmpeg.

Using FFMpeg it is relatively simple to query an existing video file to find details such as video codec, audio codec, bitrates, duration and dimensions.

Use the following FFmpeg command in a terminal window:

ffmpeg -i input_file.extension

FFmpeg will just open your input file without doing anything to it. Something like this will be returned in the terminal window:

phillc@phillc-laptop:~$ ffmpeg -i 848_Termi.mov
FFmpeg version SVN-r11213, Copyright (c) 2000-2007 Fabrice Bellard, et al.
configuration: --enable-gpl --enable-pp --enable-libvorbis --enable-libtheora --enable-liba52 --enable-libdc1394 --enable-libgsm --enable-libmp3lame --enable-libfaad --enable-libfaac --enable-libxvid --enable-pthreads --enable-libx264
libavutil version: 49.6.0
libavcodec version: 51.49.0
libavformat version: 52.2.0
built on Dec 13 2007 20:20:36, gcc: 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '848_Termi.mov':
Duration: 00:00:51.7, start: 0.000000, bitrate: 862 kb/s
Stream #0.0(eng): Video: h264, yuv420p, 480x360 [PAR 0:1 DAR 0:1], 25.00 tb(r)
Stream #0.1(eng): Audio: mpeg4aac, 44100 Hz, stereo
Must supply at least one output file

All very interesting, but what if you want to do something more with this information, like write it to a file for use in another program, or just want a more convenient way of viewing the details without having to remember an FFmpeg command? Write a small script to do the work for you. Here's one I created earlier in Perl.......

#!/usr/bin/perl

# Read command line input file
 
$input_file = shift;
 
# Read details of input file and display to user
 
$ffmpeg_input_details="ffmpeg -i ${input_file} 2>input_file.txt";
system($ffmpeg_input_details);
 
open(INPUTFILE,"input_file.txt");
@inputfile = <INPUTFILE>;
@input_file_video = grep (/Video:/i, @inputfile);
@input_file_audio = grep (/Audio:/i, @inputfile);
@input_file_duration = grep (/Duration:/i, @inputfile); 
 
print "Details for the file $input_file.\n";
print "It contains the following video data:\n"; 
print "@input_file_video\n";
print "It contains the following audio data:\n"; 
print "@input_file_audio\n";
print "It has a duration and bitrate of:\n"; 
print "@input_file_duration\n";

To use this script simply type the following at your command prompt:

perl scriptname.pl input_file.extension

Good luck extending this small script for your own uses.

I wanted to install FFmpeg on my Ubuntu Gutsy Gibbon (7.10) desktop machine. This is so I can encode and transcode video files to various formats locally, and also render projects from the non-linear editor (NLE) PiTiVi.

This post will mainly cover just the commands I used to install FFmpeg on Gutsy, with very little commentary regarding why or how things work. If you want a more in-depth look at installing FFmpeg, you can read about the installation of FFmpeg on my Debian Etch server earlier today - which ultimately moves me closer to on-the-fly video transcoding of user submitted content on Kapital Moto TV

Installing FFmpeg on Ubuntu Gutsy:

sudo apt-get build-dep ffmpeg

sudo apt-get install liblame-dev libfaad2-dev libfaac-dev libxvidcore4-dev liba52-0.7.4 liba52-0.7.4-dev libx264-dev libdts-dev checkinstall build-essential subversion

svn checkout svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg

cd ffmpeg

make distclean (I used this because I already had an older SVN snapshot of FFMPEG downloaded, configured and made from last night)

./configure --enable-gpl --enable-pp --enable-libvorbis --enable-libtheora --enable-liba52 --enable-libdc1394 --enable-libgsm --enable-libmp3lame --enable-libfaad --enable-libfaac --enable-libxvid --enable-pthreads --enable-libx264 --enable-shared

make

sudo checkinstall

Some things you might want to do when prompted to by checkinstall:

  • Select 0 change maintainer name
  • Select 3 to set version name. I used svn11213-ubuntu-gutsy-20071213

And that's it FFmpeg installed on Ubuntu Gutsy.

Other links:

I have to say, that the video manipulation program FFmpeg, while very powerful, is not very user-friendly when it comes to installation. While many Linux programs can be happily installed from either a pre-compiled package, or downloading source and compiling yourself, this isn't necessarily the case with FFmpeg. The ease of FFmpeg installation largely depends on how many different video codecs and containers you want to be able to input or output. The greater the number, the exponential increase in installation difficulty. My main need was for FFmpeg to accept a wide range of input formats, while outputting H.264 encoded QuickTime (MOV) files. Here's how I achieved this on a Debian Etch server........

I'm going to assume that you are familiar with using the Linux command prompt, moving between directories, editing text files and have at least some experience compiling programs.

The first thing I would recommend doing is making an addition to your source repository lists.

pico /etc/apt/sources.list

Add the following line:

deb http://www.debian-multimedia.org stable main

This repository contains some essential libraries for xvid and x264 (an open source H.264 codec) amongst other things. You'll need to install some software from here. The software may well be available from other repositories too, that are already in your sources.list file, but add this one to be safe.

Next rebuild your sources:

apt-get update

I would also recommend installing checkinstall. This program can be used instead of a regular "make install" command and produces a deb package file that will make re-installation or multiple machine installs much easier. If checkinstall isn't already on your machine download it from:

http://www.asic-linux.com.mx/~izto/checkinstall/download.php

Maybe navigate here with lynx, maybe use wget once you've found the actual file you need, maybe download it with a GUI based web browser and then copy it to your desired directory. It's your choice. I grabbed the latest .deb package. After the download, execute the following as root:

dpkg -i checkinstall_1.6.1-1_i386.deb

Checkinstall should have happily installed on your system. Now it's time to really get into FFmpeg.

Build the dependencies:

apt-get build-dep ffmpeg

Next we're going to install a whole lot more useful software that will allow FFmpeg to output many more than just the minimal file types.

apt-get install liblame-dev libfaad-dev libfaac-dev libxvidcore4-dev liba52-0.7.4 liba52-0.7.4-dev libx264-dev build-essential subversion,

We've also ensured that you have the necessary tools installed to compile from source (build-essential) and obtain files from the Subversion version control repositories.

We're ready to checkout FFmpeg itself:

svn checkout svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg,

At the time of writing the latest revision was 11212. If you'd feel more comfortable not using the lastest bleeding edge version of FFmpeg, issue the Subversion command as follows:

svn checkout -r 11212 svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg

This will ensure that you are also downloading the 11212 revision. Once downloaded, move into the ffmpeg directory (cd ffmpeg) and configure:

./configure --enable-gpl --enable-pp --enable-libvorbis --enable-liba52 --enable-libdc1394 --enable-libgsm --enable-libmp3lame --enable-libfaad --enable-libfaac --enable-pthreads --enable-libx264 -enable-libxvid --enable-shared

So, what have we done here......

The essence of his information, and many more options, can be found by typing ./configure --help first.

(You might also consider including libtheora in your configuration, but I forgot at the time)

We're now ready to make the installation files so at the command prompt:

make

If something goes wrong, and you need to start again, a useful command to know is:

make distclean

Make sure you do this first and then run the configure command again.

A finally:

checkinstall

You will be asked a few questions, which should be straightforward enough to answer - yes to creating the documentation, choose a name, select D for Debian package, lastly select number 3 and type a version name that means something to you. Mine was svn11212-etch-20071213. Checkinstall will now create a Debian package of FFmpeg, bespoke for your system with the configuration options you've selected earlier. Checkinstall WILL NOT install the package, so don't forget to do that:

dpkg -i ffmpeg_svn11212-etch-20071213-1_i386.deb

With some small amount of luck, you should now have a working version of FFmpeg installed on your Debian Etch server. You will be able to output H.264 encoded files in a variety of containers.

Now the fun part really begins as you spend days tinkering with commands to output the best possible files. Documentation for using FFMPEG can be found at:

http://ffmpeg.mplayerhq.hu/ffmpeg-doc.html

Have fun!

(Credit for getting me started in the right direction goes to Paul Battley and his FFmpeg Ubuntu Feisty install how-to)

About this Archive

This page is a archive of entries in the How-To category from January 2008.

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