Compression Hell

[Walter Biscardi]

[antonbradley] “but looks horribly grainy and stretched on a Big Screen (Plasma).”

Sounds like a 4:3 project stretched to 16:9. Turn off the stretch on your plasma screen.

[antonbradley] “Now some of the footage was grainy to begin with but definitely looks al lot worse due to the mpeg2 conversion.”

This is normal. Any imperfections in the original footage will be compounded by the additional compression for MPEG-2.

[antonbradley] ”
– Will I get a better big screen picture by changing my FCP sequence setting frame size to something like 960×720? And how would this play back on a small TV?”

Nope, this will look worse because you’ll take your DV footage and blow it up about 150% or so to fill the DVCPro HD frame size and then compress that. It will look better on the big screen if it was originated in HD.

[antonbradley] “Will changing my codec to Uncompressed 8 or 10 bit make the mpeg2 conversion better, thus a better DVD picture?”

Nope. You can’t “magically” add picture quality by switching to an uncompressed timeline. Your DV is what it is from the camera originals.

[antonbradley] “- What about the Anamorphic 16:9 checkbox in the sequence settings? Should this be checked or should I select this at the mpeg2 compression stage. Should this option be selected as standard so that the picture doesn

[Antonbradley]

Thanks Walter,

Question on the widescreen setting

[David Roth weiss]

[antonbradley] “The file size of the compressed 4min music video on the DVD is 213.5 MB and The size of the full resolution of the FCP Quicktime file is 868.5 MB, how can I increase the size of the compressed mpeg2 so that it looks better?”

Anton,

While this may sound logical, it is not when encoding MPEG2 for DVDs. In fact, you have already pushed your bitrate way too high. In your post you stated that your Compressor settings included “Average bit rate: 9mbps & Max bit rate: 9mbps,” indicating that you have significantly boosted the bitrate of the presets, which are by default 6.2 Mbps and 7.7 Mbps. That is a very common mistake and it is probably causing your issues not curing them.

DVD playback has limited throughput of about 10Mbps total, which is the combined bitrate of both audio and video, as well as any additional overhead required for navigation etc. By boosting the video bitrate so high you are more than likely exceeding the 10MBps limitation, and that is, if anything, creating artifacts.

FYI, most compressionists actually reduce the max bitrate to 6.8 or 7.0 Mbps in order to insure they have plenty of headroom.

BTW, in your example the original did not look very much better than the encoded sample. If all of the artifacts that are so apparent on your screen grab are actually in the original you’re never going to make find an encoder that will make them perfect. However, using a video noise filter (there is one in Compressor) will help a bit.

David Roth Weiss
Director/Editor/Post-production Supervisor
David Weiss Productions, Inc.
Los Angeles

[Antonbradley]

Thanks David,

I’ll try the settings – another thing I just thought of: I’m burning and watching the dvd’s on rewritables: DVD-RW (as it’s the only dvd’s my drive can burn). Could this have an impact on the playback quality?

Thanks

Anton

[Antonbradley]

Hey I just read another thing on LAFCPUG that could have an impact on the conversion:

https://www.lafcpug.org/Tutorials/basic_export_files.html

“I just learned two other tidbits on using the Compressor 1 shipped with FCP: using “Motion Estimation (Best)” may cause vertical jitter in your MPEG-2 movies. This problem can be avoided using “Motion Estimate (Better)”.

As I’m stil on ver. 1 – Is the above statement true and should I keep to the ‘better’ setting instead of best?

Thanks

Anton

[Walter Biscardi]

[antonbradley] ”
Question on the widescreen setting

[David Roth weiss]

[walter biscardi] “there’s no way to make it look correct on a widescreen TV”

Furthermore, if you stretch it, then your audience will have to watch it stretched. Now, if they have widescreen TV they can choose to watch it 4×3 or stretched to 16×9.

[David Roth weiss]

Rewritables are good for testing, but the dye they use in them usually burns up sooner than you’d imagine, so don’t use ’em for anything important.