Vegas Pro quick question

[ingeborgdot]

What settings would you set the render to be in the Main Concept settings? For a football game would you do a constant or variable? If constant, what would you set it at for a 55 min video? If variable, what would you use? Thanks.

[guns1inger]

Assuming this is for DVD, at 55 minutes you could do a constant bitrate at around 9200Kbps. DVD maxes video at 9800 Kbps, however some players struggle to maintain this from burned media, so it is usually recommended that you keep it lower. Remember that you still have to add the audio bitrate on top of this figure to get the total bitrate. Your other option would be to do a 2 pass VBR with a lower average - say 8700 - with a maximum of 9200. Or try both, and see which one works best.

[ingeborgdot]

Yep, sorry DVD. Is one better than another? Is constant better than 2 pass VBR? What is your take on this? Thanks.

[edDV]

Yep, sorry DVD. Is one better than another? Is constant better than 2 pass VBR? What is your take on this? Thanks.

Your sports example is similar to the handheld camcorder case. That is interlace video (unless recorded 720p) and lots of motion bursts. In these cases, CBR is best used for recording. VBR is optional for post encoding to allow for smaller files.

For recording, CBR at max bit rate means that none of the action gets lost. This is why most pro formats (e.g. DV, DVCPro, HDV, XDCAM, HDCAM) record at high constant bit rate.

Consumer camcoder/capture device formats (e.g. AVCHD, TV tuners with hardware MPeg encoders) often attempt VBR on acquisition in an attempt to conserve recording media consumption. The problem is the reaction time for motion detection. A shift from stationary to fast motion (e.g. football hike or basketball tip) may result in compression artifacts during the action transition.

When encoding after editing, the encoder has the luxury of motion analysis without real-time constraints. This is done for both single pass and two pass encoding (at least for the Mainconcept MPeg encoder*). Motion analysis is done several frames ahead so the encoding VBR transistion from low to high can be done with anticipation. This means the encoding bit rate can be reduced during periods of low motion (assuming low noise) with little quality loss. Noise will distort motion analysis making the video seem to always be in motion.

Single pass VBR encoding from a CBR source will allow reduced bit rates during periods of low motion and full (max) bitrate during action. The average bit rate setting acts as aggressiveness instructions to the encoder for bit rate reduction. The problem with single pass VBR is the final file size becomes unpredictable. Two pass VBR encoding performs an analysis pass for motion profile allowing optimization to a specified file size (e.g. 4.3 GB to DVDR).

The success of VBR for potential file size reduction depends mostly on camera stability (e.g tripod, Steadicam) and noise. Noise depends mostly on set lighting. When video is shaky and noisy, motion detection tends to low differentiation between high and low motion. When this happens, the encoder must apply a brute force bit rate reduction to the specified average bit rate causing increased artifacts over the full duration of the program.

For sports programming, golf or baseball would respond best to VBR due to long periods of low motion locked camera shots. Basketball and hockey are the worst since the cameras are in near constant pan and zoom.


* The Mainconcept MPeg encoder has a realtime mode for capture where motion detection reacts in realtime. In this case, video must be buffered to allow the motion detector to work in advance. If the buffer fills, frame loss occurs.

[ingeborgdot]

WOW!!! Thanks. Ok, I get it that constant would be best for football. I do have a question on what you are saying in the last paragraph about the Mainconcept MPeg encoder. Is this good, bad or what? What would you use?

[edDV]

WOW!!! Thanks. Ok, I get it that constant would be best for football. I do have a question on what you are saying in the last paragraph about the Mainconcept MPeg encoder. Is this good, bad or what? What would you use?

The key issue with football is record at high bit rate CBR or uncompressed. Then when re-encoding after editing, set a high bit rate. This means edit it down so you can you can use 1Hr 9500 Kbps CBR mode.

If you need it to go longer use two pass VBR mode and use the full 4.35 GB of disk capacity. The length of time determines the "avreage bit rate". Set maximum at 9500 Kbps and minimum down around 1500 Kbps. The more video you put on the disc over one hour, the lower the quality will be.

If you are encoding while capturing, it is best to use a hardware MPeg2 encoder or use 9500 Kbps CBR. Software MPeg encoders will have low quality in realtime VBR mode. Among the best of the realtime software encoders is Mainconcept if it has the realtime module. The Mainconcept encoder in Vegas Pro does not include the realtime capture module.

[ingeborgdot]

The football comes from a SD camcorder right now. Most of the time the game overall is less than 60min. I use the vegas capture to capture from the camcorder. I then edit and render in Mainconcept to get it ready for DVD Architect.

"If you are encoding while capturing, it is best to use a hardware MPeg2 encoder or use 9500 Kbps CBR. Software MPeg encoders will have low quality in realtime VBR mode. Among the best of the realtime software encoders is Mainconcept if it has the realtime module. The Mainconcept encoder in Vegas Pro does not include the realtime capture module. "
I don't really understand this part. I do but I don't if you know what I mean.

What would you do if you captured from a SD camcorder into Vegas Pro and used DVD Architect author and burn the DVD?

[edDV]

The football comes from a SD camcorder right now. Most of the time the game overall is less than 60min. I use the vegas capture to capture from the camcorder. I then edit and render in Mainconcept to get it ready for DVD Architect.

"If you are encoding while capturing, it is best to use a hardware MPeg2 encoder or use 9500 Kbps CBR. Software MPeg encoders will have low quality in realtime VBR mode. Among the best of the realtime software encoders is Mainconcept if it has the realtime module. The Mainconcept encoder in Vegas Pro does not include the realtime capture module. "
I don't really understand this part. I do but I don't if you know what I mean.

What would you do if you captured from a SD camcorder into Vegas Pro and used DVD Architect author and burn the DVD?

You are doing fine.

Your camcorder is recording CBR (probably 25 Mb/s DV format). If your edited program is less than or equal to an hour, you can use 9500 Kbps CBR for MPeg2 encoding. If it goes long, say 80 minutes you would use two pass VBR with 9500 Kbps as max bitrate and 7300 Kbps for average (from bit rate calculator).


https://www.videohelp.com/calc

The real time case would be like recording a TV broadcast directly to MPeg2.