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Calculate output size when conversting to DVD format

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Alex Pavlov
Calculate output size when conversting to DVD format
on Mar 25, 2011 at 2:47:09 pm

I am writing DVD Creator. So I need to somehow calculate the estimate output size of converter mpeg files. I use FFMPEG for conerting and its Target parameter for converting video to DVD-compatible .mpeg file. But there is no fixed bitrate when it converts the files, so I don't know how to calculate estimated output size of the movie.
Please help me with this question. Thanks in advance.


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Michael Rampe
Re: Calculate output size when conversting to DVD format
on Apr 1, 2011 at 10:29:56 pm

Try using the -b bitrate setting on two pass encoding. This will produce a file very close to the specified bitrate. For dvd you may need to use -maxrate, -minrate and -bufsize as well to ensure the stream is compliant.

Michael


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Alex Pavlov
Re: Calculate output size when conversting to DVD format
on Apr 3, 2011 at 8:24:22 am

Thank you Michael. But what if I set maxrate = 2000K instead of 9000K?
And then calculate total size like
sz:=((VideoBitrate/1000)/8)*totalsec+((AudioBitrate/1000)/8)*totalsec;
(where VideoBitrate = 2000K and AudioBitrate=448000. totalsec is a length of the movie). What do you think?


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Michael Rampe
Re: Calculate output size when conversting to DVD format
on Apr 3, 2011 at 9:00:35 am

[Alex Pavlov] "Thank you Michael. But what if I set maxrate = 2000K instead of 9000K?
And then calculate total size like
sz:=((VideoBitrate/1000)/8)*totalsec+((AudioBitrate/1000)/8)*totalsec;
(where VideoBitrate = 2000K and AudioBitrate=448000. totalsec is a length of the movie). What do you think?"


2000k seems a bit low. do some tests to find a good quality/size setting.

Also, maxrate requires bufsize to be set.

not sure of your equation. video bitrate is in Kbits, audio bitrate is only in bits in your example (assuming 48000 instead of 448000) Do you want the output in Megabytes? If so with video at 2000K and audio at 48K I guess it would read ((2000+48)/1024/8)*totalsec

Michael


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