But the bitrate distribution is much less precise than it would be in a real 2-pass mode.Acer laptop user manual.
This is repeated until the end of the movie, mostly this method does reach the requested target size. After encoding maybe 2% of the source at this quality the resulting output size is compared to the desired output size, then the quantizer is adjusted dynamically. The encode is started at a fixed quality setting (quantizer in this case). One popular method uses sample encodes of 5% or 10% of the source. To avoid the low speed of 2-pass several different methods for 1-pass VBR were developed. The second pass uses this compression curve to determine the optimal bitrate for every section of the source. The first pass is only used to analyze the compressibility of the source and to create a compression curve. 2-pass (or multi-pass) is the straightforward way to achieve this. But if you want to burn the result on an optical disk it is important that you can reach a certain desired size. But in its pure mode the user has no control over the resulting file size.
Variable bitrate is always superior to constant bitrate in terms of quality. You have to decide yourself which mode is better for you. In 1-pass VBR mode the bitrate distribution fluctuates much less than in 2-pass mode, sometimes it even looks more like CBR than VBR. If you want to compare the different bitrate distributions between 1-pass and 2-pass you can use a bitrate viewer. But this also depends on the source characteristics, and it is for the user to decide if this quality improvement justifies the much longer encoding time. At least for lower bitrates this should result in a visible quality improvement.
The general advantage of 2-pass VBR compared to 1-pass VBR is the better bitrate distribution over the whole file. This will override any thresholds in the "ff_vbr.ini" file. The modes can directly be specified under the DVDStyler Core settings.
Tuto dvdstyler software#
When Alex integrated the VBR plugin into the software he introduced a different method to select the encoding modes. By default the threshold for 2-pass is at 4500 kbps, but this can and should be changed for different quality needs. The bitrate thresholds can be edited in the file "ff_vbr.ini" in the "DVDStyler\Lib" folder. This means that the encoding mode is selected automatically according to the video bitrate.
Tuto dvdstyler download#
Download link is in this post:Īfter a fresh installation DVDStyler defaults to the FF_VBR auto mode. First thing you should do after installing the latest Beta3 is updating the file "ffmpeg-vbr.bat".
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