Re: Audio and video editing?
 

I think GStreamer is better but I find less documentation tool and I see it initially more difficult than ffmpeg.

Maybe we should try to take small tutorial to get tips Gstreamer until a GUI.

Re: Audio and video editing?
 

A tutorial would be highly appreciated; also, maybe if those of you who know Python well could have a look at it? See the last 3 paragraphs of this post for the reason why. ;)

I tried to inform myself and get an idea about GStreamer; plus, I wanted to write a shell script as a proof of concept that would take 3 seconds from video A, 3 seconds from video B and encode them to a new video C.

The good news is: I found out GStreamer is much, much more powerful than I had originally thought. It would allow things like recording live audio comments to your edited videos or even picture-in-picture effects, showing your face on the upper right while you comment what's being shown on the main video. It supports conversion (framerates, 16:9 crop to 4:3 etc.), still images as part of the video, text overlays etc etc. ... in theory. If the N900 is powerful enough to handle it and if all the components are installed.

Another advantage seems to be that a lot of the components I did find are installed on the N900 seem to make use of the DSP or are nokia-specific; I simply assume (without knowing ffmpeg and mencoder) that this would help encoding performance-wise in comparison to these two other alternatives.

Last of the good news is that I even got one simple thing working from the command line on my N900 - the playback of one video file I had recorded:

gst-launch is the command, the rest are parameters. This does nothing but play back a file, without any manipulation.

One site I found, the Gstreamer Cheet Sheet, gives you an idea of how huge and complicated these gst-launch command lines can become; the syntax isn't really nice. ;)
But then, if you write an application using GStreamer, you would use it's API and construct the monster one item at a time.

Now for the bad thing - and what I couldn't get to work yesterday:

Once I ran into a problem, I couldn't identify what exactly I'd been doing wrong because the error messages don't mean nothing to me. I copypasted code from the web that involved the gnonlin-component (which is what we need for editing videos) and tried to run it on my desktop (Ubuntu) - errors, errors and no help.
Of course part of my particular problem seems to be that most useful examples about editing videos with Gstreamer and gnonlin are published in Python, not as gst-launch command lines. I don't want to learn Python now while I try to understand Gstreamer... too much. ;)

Maybe people with a solid knowledge of Python could better understand the examples available and apply the necessary changes to make them run on the N900.

I found this page promising.

Re: Audio and video editing?
 

I think GStreamer is more powerful but less intuitive, we become accustomed to over the Syntaxis type ffmpeg.

Gstreamer trying to understand how it works:

There are three basic components: 1 src (input); 2 Filters, convertors, demuxers, muxers and codecs, 3 º sink (outputs).

Everything is based on an input connected to another element, can be a black box (filters, convertors, etc), or an output.

The tickets we recognize that contain the string "src" and outputs the string "sink."

example: gst-launch-0.10 v4l2src! xvimagesink

To find the available inputs, outputs, and plugins will use the command "gst-inspect." This command lists all available plugins and a brief description of what they do.

If you want more information and to manage parameters write "gst-inspect <<object>>." For example "gst-inspect vertigotv" showing a result ...

Re: Audio and video editing?
 

I actually did get a simple "cut and merge" running on my ubuntu PC during the weekend, using Gstreamer's gnonlin component; I still don't know what I do (I copy and paste from the web and then use trial and error to change it until it works), so ATM I can take pieces of video and put them together - but they're missing the original soundtrack. I'll have to check that. Next thing would be to get it running on the N900 with gnonlin installed from extras-testing.

Re: Audio and video editing?
 

I think GStreamer is more powerful but less intuitive, we become accustomed to over the Syntaxis type ffmpeg.

Gstreamer trying to understand how it works:

There are three basic components: 1º src (input); 2º Filters, convertors, demuxers, muxers and codecs; 3º sink (outputs).

Everything is based on an input connected to another element, can be a black box (filters, convertors, etc), or an output.

The tickets we recognize that contain the string "src" and outputs the string "sink."

example: gst-launch-0.10 v4l2src ! xvimagesink

To find the available inputs, outputs, and plugins will use the command "gst-inspect." This command lists all available plugins and a brief description of what they do.

If you want more information and to manage parameters write "gst-inspect <<object>>." For example "gst-inspect vertigotv" showing a result ...

If we look shows that it has the ability to work with video signals and RGB type.

This forces us to make a video to rgb before or filter would not work.

Another detail is that you tell which codec to use when working with video or audio, well now we no longer "decodebin" to find out if the codec used in audio / video knowledge and leads to the default output.

It is important to understand that to link all plugins should be used pipes are represented by the symbol "!".

Example:
If we look shows that it has the ability to work with video signals and RGB type.

This forces us to make a video to rgb before or filter would not work.

Another detail is that you tell which codec to use when working with video or audio, well now we no longer "decodebin" to find out if the codec used in audio / video knowledge and leads to the default output.

It is important to understand that to link all plugins should be used pipes are represented by the symbol "!".

Example:

We will play only one video file video / audio.

gst-launch-0.10 filesrc location=/home/usr/MyDocs/.videos/9.mp4 ! decodebin ! xvimagesink

Now we will apply a dizzying effect on the image and in real time.

gst-launch-0.10 filesrc location=/home/usr/MyDocs/.videos/9.mp4 ! decodebin ! queue ! ffmpegcolorspace ! video/x-raw-rgb ! vertigotv ! xvimagesink