Saiweb

Ok I purchased Jing PRO to do some more video posts to saiweb … unfortunately the MP4 quality is lack luster.

To be honest I’d rather have a large size MP4 I can run through my own encode (i.e. FFMPEG) and get the quality I want …

Off goes the email to support … wooo ….

NOTE: You may have to watch the vid in fullscreen to view it properly, I have scaled the player down to fit the blog page width.

Liam (http://goodingsweb.com) has shared his findings on tweaking ffmpeg output with h.264, he has taken a 174MB flv file down to just 24MB (86% reduction in file size).

There is no noticeable difference in quality either, you can follow the forum thread here: http://flowplayer.org/forum/7/12671.

Click the video for a preview of Liam’s settings:

Well the intrest in this subject seems to be picking up!

I am currently researching two pass encoding using libx264 and libfaac to allow low bitrate (fast loading) HD streaming.

As I figure this out you can see the results here: http://www.saiweb.co.uk/linux/very-basic-c-gdb-tutorial

The embeding is handeled using a wordpress plugin I have written, I will make this available shortly.

I will be getting part one “FFMPEG” installation up today regardless.

The thing that has realy annoyed me lately is the lack of documentation to be found for FFMPEG, the documentation you can find is by way of MAN pages, and makes the assumption you allready know all the terms that go with video encoding.

Well I am to change that.

Over the next few days I will be producing a Video set “Build your own HD YouTube” covering installation of FFMPEG, to building a basic PHP front end (without using PHP-FFMPEG), and finaly a summary covering methods you should use if you want to use the methods covered in a production envrionment.

ffmpeg comes with a tool to re-order the MP4 “atoms” (Seriously don’t ask what are MP4 atoms it’s geek for the sake of geek).

find the file in ffmpeg_src/tools/qt-faststart.c

compile with gcc

And run.

NOTE: This only seems to work for h264 encoded videos (libx264).

Just try to find documentation on this … absolute nightmare is an understatement, so here are my notes of the steps I took to compile ffmpeg with a selection of codecs:

NOTE: The above are current at the time of writing, check for more recent versions at the relevant sites.

Extract:

cd to relevant directories and run the following:

faac & faad2: ./bootstrap && ./configure && make && make install
xvidcore: cd build/generic; ./configure && make && make install
libx264: ./configure –enable-shared –disable-asm && make && make install
The rest: ./configure && make && make install

NOTE: You must install libogg prior to libvorbis and libtheora

The following is required otherwise ffmpeg will display errors about being unable to find libraries:

i.e.

FIX:

You must run “ldconfig” any time you install a new lib you want to use with ffmpeg!

Install FFMPEG

NOTE: If you allready havea checkout of ffmpeg and run an update to get the latest code, make sure you run

Prior to running the configure line.

et voila job done ….

The information for this is VERY very sparse, so here is a summary of what I have found.

Install libx264

Get the libx264 package from here: http://www.videolan.org/developers/x264.html

Extracts the bz2 file

And now the useual

Get a nice error message:

You do want MMX/SSE at somepoint for the time being I am disabling this though (lack of time to find a valid RHEL source). so I added the disable asm line.

Install ffmpeg

For this I use subversion.

et voila ffmpeg is now installed with libx264 (h264).

error while loading shared libraries: libavdevice.so.52: cannot open shared object file: No such file or directory

To fix this:

Add the line : /usr/local/lib

And run ldconfig.

UPDATE: I am writing a full set of notes blog entry for installing ffmpeg with codecs on RHEL4