Before considering the merits of this, it is good to put the record straight. In particular, it is right to ask yourself a question: if we have a collection of video in DivX format (for example, our favorite TV shows purchased from VHS thanks to a dedicated video card) because we should have the need to convert them to VCD (MPEG 1) ?
Improving quality videos using the DivX Codec
The question is legitimate, especially considering the quality of the VCD is low (comparable, so to speak, to that of the old VHS) and the compression format MPEG 1 occupies more space than an MPEG 4. Not to mention that often a movie in DivX, which was comfortably on a CDROM 700 Mb, after treatment will require at least two CDs. There is a simple answer: most home DVD players currently in circulation supports
At this point, however, could rise another objection: why convert DivX to VCD and SVCD format (MPEG 2), which provides a quality much better?
For two reasons: first, the SVCD take up much more space than the VCD; second, if it is true that the majority of DVD players are compatible with VCD, you can not say the same regarding Super Video Compact Disc. In any case, in future issues of Computer Idea explain how you create SVCD. To make the process of converting the subject of these pages must be developed through two programs: TMPG Encoder and Ahead Nero Burning Rom (see the box “Hardware and Software”). The first is for the transformation of the DivX MPEG 1 (and possibly to divide the movie in two parts) and the second to create and burn a Support multi optical as the CD-ROM, VCD.
After downloading the program TMPG Encoder (simply called TMPGEnc) from the site www.tmpgenc.net , unzip the contents of the zip file to a new folder and double-click the file “TMPGEnc.exe”. When the program starts, automatically starts the wizard (wizard): remove the check mark next to the phrase ” Enable this wizard at startup “and click” Cancel “. There is therefore the main program screen. Concentrate on the lower section. Thanks to the frame “Video source” (and the corresponding Browse button) indicated in the program what is the file compressed in DivX format (and therefore with AVI extension) that you want to put “under the knife”. If the movie shown was created with MP3 audio , the same file will be automatically loaded in the “Audio source”. In the “Output file name” must enter the path and name of the file to be created (the one in MPEG 1, for instance); must have the extension “.mpg”. Check also that in the “Stream type” is ticked the option “System (Video + Audio)”. At the end of these configurations, click the button Setting.
The ” MPEG Settings “allows you to define the characteristics of the movie that we will create. The first menu that appears is “Video”. Set the options as shown in the figure. In particular, in “Stream Type” must be set to “MPEG-1”; as regards the video resolution, in the “Size” (size) set the standard values for PAL 352 288 pixels, and in the section “Aspect ratio” specifications “4: 3 625 line (PAL)”. The “frame rate”, namely the maximum number of frames that the graphics chip must process per second (fps), must be set to the value 25. The “Rate control mode” should be constant (CBR), the bitrate must be set to 1150 Kb per second and the “VBV buffer size” to 100 Kb. Ultimately you need the value of “Motion search precision”, which in practice means the quality / speed of the encoding. If you do not have a very powerful computer, the advice is to set thanks to the pull-down menu, the value “Normal”.
In the next tab (Advanced) focus primarily on the ” Video source setting . ” Here you set the values “Non-interlace (progressive)”, “Bottom field first (field B)” and “1: 1 (VGA)” in their three fields. In ” Video arrange Method “should be set to” Full Screen “(full screen). In the lower part, then, you have several filters to improve the final product: recommend selecting only the “Ghost reduction”, which helps to improve the video quality by minimizing some artifacts typical compression MPG. In MPEG compression only some frames are captured “full” (“I frames”) while the other (P and B frames) are obtained by knowing the differences with the frames which precede or follow them, in a sort of “interpolation”. The order in which successive I, P, B frames is called “GOP Structure.”
In the relevant data set the following values: 1 for the “I”, 3 for “P”, 2 for “B” and finally 1 for “Output interval”, as shown in FIG. Finally, select the box ” Detect Scene Change “and go to the next tab.