GTranscode Interface 

Its a pretty simple interface hiding a lot of powerful possibilities.

The main components of the software interface is the Input area on the left, and the Output area on the right.

Input Area

This is the section that determines what file(s) you choose to transcode (convert).

File Selector 

To choose a file or directory for transcoding you simply click on the Browse button next to Video File or Directory and this will open a file browser :

 

Of course you can Create Directories, Delete Files, and Rename Files with this interface but mainly you want to use it for choosing the files you wish to transcode. When you have browsed to the file you wish to convert into another format simply highlight it by clicking on the file name and press OK. If you wish to transcode an entire driectory then open theat directory by double-clicking on the name in the file browser, then do not select a file name, just press OK.

When you have selected the directory of file for transcoding you will see some feedback about your selection on the middle of the GTranscode input area:

 

The above is the feedback for a single file. If you have loaded a directory the feedback will look somehting like this:

You should always check the feedback to see if you have indeed chosen the right file.

import module

 

The import module decodes the input file. There are many input modules but it is best to allow the application to try and automatically recognise what the file format is and which module it should use. Do not change the default value "auto (use probed)" unless you experience problems reading the file with the application.

frames

 

You may decide to transcode only part of a video file. In which case you can enter the beginning frame and the end frame of the section to be transcoded into this field. If you wish to do this then the format would be something like f1-f2 where f1 is the beginning frame and f2 is the end frame. Here is an example:

Output Area

On the right of the interface you will see information and options regarding the type of file or files you would like to create.

Output Video File 

The Output Video File is simply the area that you use to browse to the place on your file system where you would like the file(s) to be saved. You must also specify a filename for the transcoded file. If you are not sure of the suffix to be included on the file you don't need to include a file suffix at this point. For example the following would be acceptable:

 
You can work out the correct suffix later if you need to.

Pass Through vs Full Processing

Also on the right of the interface you can choose between the Pass Through and Full Processing options.

With Full Processing the a/v stream is first decoded then encoded again into a new file. In pass-through mode it's read without decoding and written as is to the output file it's a way to convert formats losslessly.

 
Generally you will choose Full Processing.

Full Processing Options 

If you choose Full Processing you will see a further set of options:

These options define the format of the file that you will create.

Export Module 

 

The export module setting defines the format of the newly created media file. Currently Transcode and hence GTranscode converts to many formats including  DivX;-), XviD, DivX 4, DivX 5, AVI,  MPEG, raw DV, and others. For a full list please see the Transcode Wiki (http://www.transcoding.org/cgi-bin/transcode?Export_Modules) . Unfortunately GTranscode does not load in a nicely formated drop down menu so you can choose from these formats, instead you have to type the information into the export module field. For example, to transcode to DivX 5 you would type divx5 in the export module text box. Modules you could try typing in to the export module for transcoding video files include:

• mpeg2enc
• xvid
• divx5
• mpe1

Additionally you can add other options to the export module you have chosen. To do this you will need to know a few command line options from Transcode into the export module optional string. For basic use of GTranscode this field can be skipped.

frame rate

 

The frame rate is for setting the number of frames per second for the output (transcoded) file. If you leave this field the frame rate of the input file will be preserved.

deinterlace mode

 

Interlacing splits a video image into two separate scan lines in a single frame. All analog TV formats use interlaced video. Interlaced video, when viewed on a TV, looks fine but when viewed on a computer the video displays a series of lines across the video. Video files which are interlaced need to be de-interlaced to be displayed correctly on a computer. Transcoding can do this and the output of the de-interlaced video is refered to as progessive or non-interlaced video.

If you wish to de-interlace video then you will need should try the available options, perhaps starting by choosing interpolate scanlines from the available drop down menu.

antialias

 

The deinterlacing process can generate unwanted artifacts in the video in the form of "jagged" lines. To minimise this distortion you can choose various methods of video anti-aliasing. The anti-aliasing methods do not remove the distortions but disguide them so they are not as apparent. You will only need to experiment with these options if you are deinterlacing video (see above).

video bitrate

 

This option determines the bitrate of the output (transcoded) file. The bitrate is very important for the final quality of a video file. The higher the bitrate the higher the quality, and the larger the file size. If you are encoding a file for delivery over the internet or you have limited storage space the the bitrate settings become very important. The setting of the bitrate is entirely up to you, however in most circumstances you would not go below 64 kbps. To experiment you could try 100, 200, and 1600 in the field provided.

preserve aspect ratio

 

If you wish to change the height and width of the output video file then you can use these fields. If you wish to change the size of the video window but manitain the raio of height to width then make sure the box of on the left is press down. If you do this then you can enter either your prefered height and the application will calculate the correct width (or vice versa). You can however elect not to maintain the aspect ratio in which case you may get odd but interesting results.

use YUV

from the Transcode manual page: "This option is depricated. It is default now because it is  most codecs'  internal  format  so  there is no need for conversions." In other words, don't change this setting unless you know what you are doing.

Swap, flip, mirror

Don't change these options unless you want the output file to be changed dramatically.

Audio Options

This area dictates the audio transcoding output options. You can again choose between Full Processing  or Pass-Through options (see above). If you choose Full Processing  you get several options:

Full Processing 

 

audio format

Choose here from the drop down box the posisble formats you would like the audio converted too.

audio bitrate

As with the video bitrate this option plays a significant role in determining the quality of the audio and the final file size. Experiment with the values provided.

volume gain

Gain is a way to boost the audio levels. if your audio level (in the original file) is low you may wish to experiment with this value, otherwise leave it set as 1

Command Line Display

To help you learn the syntax for Transcode there is a nice output field at the bottom of GTranscode that displays the command that reflects the options you choose in the interface.