Disappointing delivery

GeeBax wrote on 5/7/2014, 1:37 AM

I have been doing some tests shooting railway subjects prior to setting out to do the real thing. I am using the Blackmagic Pocket cinema Camera, grading in Resolve and performing audio work, titling and edit in Vegas 13. My intention is to release these programs as high quality HD 1920 x 1080 with Dolby 5.1 surround sound.

My first attempt was spoilt a little by it raining just as the train arrived, but the results were sort of OK. Unfortunately I was not able to record the sound correctly, so it is only that picked up by the in-camera microphones. Actually, it is not all that bad. The delivered clip was rendered out of Resolve as a Quicktime MPEG4 clip at a high bit rate, and then further processed by Handbrake to make the clip a more manageable size.

For the second attempt, I got the whole audio thing together and produced a good audio result, but I am disappointed by the images. Resolve is a great grader, but cannot mix audio for nuts and does not have a capable titler. So I exported the images as a Quicktime YUV 422 10 bit file, and edited, titled them and mixed the audio in Vegas 13. And that where the problems arises.

When it comes time to render the output, there is only one codec offered by Vegas, Sony AVCHD, that can output the audio in Dolby 5.1 (as far as I can tell).

But the video performance is not great. To keep it within a manageable file size, I chose to render it at 4 Mbits/s, and I now find there are some annoying artefacts in the rendered image.

If you care to look, you can download the clips and view them here: http://www.hollywoodfoundry.com/film%20files.htm

The parts of the image that bother me includes the bush on the left of frame. From time to time through the clip, something seems to be possessing the bush, and also the dark green overhead foliage is badly rendered and flickering.

I would love to hear from any of you who can suggest any way to improve this.

Geoff

Comments

malowz wrote on 5/7/2014, 1:47 AM

what are the "destiny" of this files? for the web? you can use handbrake, that use x264 encoder (way better quality with low bitrates)

for audio, AAC also are multichannel. but im not sure about correct reproduction. all depend where you will play. if using VLC for instance, i believe you can do 5.1 HE-AAC audio encoding (good quality at very low bitrate)

GeeBax wrote on 5/7/2014, 2:03 AM

The programs will be sold by various railway heritage organisations from the gift shops, as either DVD, BluRay or USB Drives loaded with the files. They need to be playable by any standard consumer device but it is important that the final method allows high quality images plus 5.1 sound.

farss wrote on 5/7/2014, 2:16 AM

[I]"The parts of the image that bother me includes the bush on the left of frame. From time to time through the clip, something seems to be possessing the bush, and also the dark green overhead foliage is badly rendered and flickering."[/I]

I'm waiting for the file to download at the moment however even without seeing it the artefacts you describe are quite common when a H.264 encoder is used at low bitrates. 4Mbits/sec is very low for 1080, heck it's even low for SD mpeg-2. No doubt all the movement of a train, trees and the steam is not making for easy to encode video, I think you really need to up the bitrate significantly.

Bob.

malowz wrote on 5/7/2014, 2:20 AM

then a good start is .mp4 format, with AAC-LC 5.1 or as you doing, AC3 5.1

you can also use different encoders for audio/video and then mus A+V in the final mp4 file

there are tons of tools for this, just google ;)

GeeBax wrote on 5/7/2014, 4:52 AM

Thanks guys, all taken on board. I have now rendered it using the Sony AVCHD codec at 21.9 Mb/s, which is the highest setting it will accept, then afterwards shoved it through Handbrake. The initial file, for roughly 2 minutes duration was 385 MB, and handbrake brought it down to 114MB with no discernible loss of quality.

I think the other thing I might do is shoot another test this coming weekend at either 29.97fps or 30 fps to see if I can reduce the motion artefacts.

John_Cline wrote on 5/7/2014, 6:26 AM

What frame rate did you use to shoot it in the first place? Shooting 24p will definitely show "judder" artifacts, particularly on motion or pans. 29.97p will be marginally better, but will still judder.

Former user wrote on 5/7/2014, 7:33 AM

You can always Mux the 5.1 audio with the video. I used TSmuxer for that.

I don't understand why you would render to a compressed format and then render to another compressed format.

John_Cline wrote on 5/7/2014, 7:41 AM

You could also render your temporary files to the lossless "UT Video" codec which Handbrake will accept. Being lossless, it will make for some rather enormous files, but will maintain the highest visual quality possible when you compress for final output in Handbrake.

http://www.videohelp.com/tools/Ut-Video-Codec-Suite

farss wrote on 5/7/2014, 8:18 AM

I've only had a brief look at one of the files and nothing leapt out of the screen to scream "UGLY ARTIFACTS" at me. Admittedly that was only on the office PC. I'll try again on my HDTV later but even so it cannot be all that bad.

Bob.

musicvid10 wrote on 5/7/2014, 8:41 AM

" My intention is to release these programs as high quality HD 1920 x 1080 with Dolby 5.1 surround sound."

Four Mbps is generally way to low for 1080p delivery if there is movement in the video.
A lossless intermediate to Handbrake or frameserving to AviSynth can achieve better results at low bitrates than either of the AVC encoders in Vegas, but you can't make a silk purse from a sow's ear.

I consider 9 Mbps High Profile about the barest minimum for 1080 AVC delivery, certainly no less.

An alternative you might consider is 720p delivery, in which case 4 Mbps would be barely adequate.

GeeBax wrote on 5/7/2014, 5:39 PM

[I]What frame rate did you use to shoot it in the first place? Shooting 24p will definitely show "judder" artifacts, particularly on motion or pans. 29.97p will be marginally better, but will still judder.[/I]

It was originally shot at 24 fps, but the camera is capable of up to 30 fps, although there seems to be less encoding support in Vegas for 30 fps.

[I]I don't understand why you would render to a compressed format and then render to another compressed format. [/I]

If you are referring to putting it through Handbrake later, it is because the Sony AVCHD encoder does not do well at lower bit rates, and Handbrake does a better job of it. So I rendered it at a higher rate to get the best result, then used Handbrake to 'finesse' it down to a smaller file.

I am ftp-ing the newer file up to the web site at the moment, it is the last one called 'Puff Again 21MBs Handbrake'. I am reasonably happy with this version, but value input on the result from the members here.

I think it might be worthwhile doing another test at 29.97 or 30 fps, after all most playback devices these days don't seem to have any problems dealing with those rates.

Former user wrote on 5/7/2014, 7:15 PM

To maintain maximum quality and reduce artifacts, I would avoid rendering to a lossy compression twice. If you know you want to render in handbrake, I would recommend using an uncompressed or lossless codec for the interim render. You can always delete that file later if it is too big to store.

Lovelight wrote on 5/7/2014, 8:09 PM

Use max at 21 for avchd not 4!

GeeBax wrote on 5/7/2014, 10:08 PM

[I]To maintain maximum quality and reduce artifacts, I would avoid rendering to a lossy compression twice. If you know you want to render in handbrake, I would recommend using an uncompressed or lossless codec for the interim render. You can always delete that file later if it is too big to store. [/I]

That is good advice, however none of the lossless codecs allow encoding of 5.1 with the image.

[I]Use max at 21 for avchd not 4![/I]

Thank you, that is exactly what I did with the latest version.

OldSmoke wrote on 5/7/2014, 11:19 PM

Have you tried XAVC? I have great results with it.

GeeBax wrote on 5/8/2014, 1:21 AM

Yes, I looked at XAVC, but it also does not allow encoding of the audio at 5.1 and while I know it is possible to encode the audio and video separately, then mux them together, the last time I tried that it did not maintain sync over the length of the program.

Former user wrote on 5/8/2014, 7:23 AM

I have never had a problem with sync when muxing audio later. Your workflow seems to be adding some errors.

Are you muxing the 5.1 in the Handbrake process?

GeeBax wrote on 5/8/2014, 6:12 PM

It is some time since I performed the mux process, I did not know you could do that in Handbrake.

Does anyone have a suggestion for the best quality intermediate render codec to use in Vegas so I can then compress it using Handbrake?

John_Cline wrote on 5/8/2014, 6:55 PM

"Does anyone have a suggestion for the best quality intermediate render codec to use in Vegas so I can then compress it using Handbrake?"

I mentioned it earlier in this thread, it is the UT Video codec, it is lossless and doesn't get any higher quality than that.

musicvid10 wrote on 5/8/2014, 8:09 PM

Handbrake is not a muxer.
Lots of ways to mux your 5.1 after Handbrake.
Or even before, in MakeMKV, but that's an additional step.

My intermediate of choice is now DNxHD 444.
It will carry stereo PCM, but not multichannel.

UT is a good lossless codec that works with Handbrake, but quite a bit larger files.
Never tried multichannel audio with it, though . . .

Former user wrote on 5/8/2014, 8:22 PM

Okay sorry. I was under the impression you could bring in a video track and audio track from separate sources in Handbrake. I don't use it so I should have stayed mute.

musicvid10 wrote on 5/8/2014, 8:33 PM

It's a pretty common mispercerception, but the audio muxing is easily accomplished pre- or post-Handbrake.

Handbrake's AAC audio encoder used to be so crappy that replacing the audio after encoding was fairly routine.

GeeBax wrote on 5/8/2014, 9:08 PM

[I]I mentioned it earlier in this thread, it is the UT Video codec, it is lossless and doesn't get any higher quality than that.[/I]

Thanks John, I did miss that. However I could not find anything in the choice of codecs on offer in Vegas that matched the description 'UT Video"?

And thank you also musicvid10, I will look about to see if I can find a suitable muxer.

musicvid10 wrote on 5/8/2014, 9:59 PM

Both Avid DNxHD (LE 2.3.8) and UT video come from third parties, are downloaded from their sources, and install as MOV, and AVI VFW respectively in Vegas.
Best.