Flie Size Is Larger After Encoding at Lower Bit Rate

[KevMull]

I'm using TMPGenc 2.5.

I have a short mpeg clip that was originally encoded at 9800 vbr.
The file size is 500mb

Problem is I want to author it in ULead DVD Workshop 2 but it won't have it because it complains that the bitrate (9800) is too high.

So I tried re-encoding it (video only, prog stream) in TMPG at 7000 (VBR), Quality set at 80 and 'Motion Estimate=fast'. Problem is it has now increased in size at 650mb!! and that's without the audio.

I need to keep the filesize at least the same or lower than the original else it won't fit onto ny DVD.


Why has it increased since I reduced the settings?

Many Thanks

[Warrych]

The length of the output is related to the quality in this settings.

If you want total control over the file size, I would highly recommend using 2-pass VBR. The file size will be:

[filesize in kbits] = ([average bitrate video in kbits/sec] + [bitrate audio in kbits/sec]) x [length of the movie in sec]

(1 byte = 8 bits, 1 MB = 1024^2 bytes = 1048576 bytes, so: [file size in MB] = [file size in kbits] / 8388.608)

Conclusion:

[average bitrate video in kbits/sec] = ([file size in MB] * 8388.608 / [length of the movie in sec]) - [bitrate audio in kbits/sec]

Because of the limitations of the DVD-standard and due to DVD-player compatibility reasons I would recommend using 800 kbits for minimum and 9400 kbits for maximum bitrate.

(The max. bitrate of video and audio combined should not exceed 9848 kbits/sec. If the bitrate drops below 800 kbits, some DVD player will produce dropouts.)

If you still want to use the original file, TMPGEnc DVD Author will accept the movie - after you have clicked away some warnings - but it is likely that you will face problems playing the DVD on some stand alone players.