Saving, Exporting individual edited tracks in VPX 2017

Craigster wrote on 9/22/2017, 3:12 AM

I am starting a series of video projects with a couple other guys who are mac based and use FCP (both X and 7Express). Coming from Samplitude ProX, I can export audio tracks as .wav files. I'd like to be able to do a similar thing with video/audio tracks from VPX. Just not sure how. Most of the export features are for full movies (not tracks) or for copying existing Magix projects (i.e. for backup).

Here's a scenario:

I import 40 minutes of video from 2 cameras and my Samplitude mastered audio track into VPX.

So, I line up the audio, choose my segments, make my edits. So, now I have 5 minutes of edited video for the intended project goal: Still 2 camera tracks (with original audio), plus preferred audio. Now that I've made the rough cuts, I want to hand off the tracks (2 video/audio and 1 audio) to another producer to take on the next step of production (i.e. color editing, transitions, titling, fx, intro/outro etc.).

So, I want to export the 5-minute video and audio tracks, to be usable elsewhere. (Not the 40 min. originals).

Can VPX do this? If so, how?

If not to another program, can I copy/save just the edited amounts in another folder my usage later (i.e. not full files; just my now-edited ones)? This would be like the "Save Complete VIP in..." feature in Samplitude that lets a user save a smaller version of only used samples (not deleted ones). When I tried export a marked range, it still exported the full (uncut) project.

Suggestions?

Many thanks!

Craig

Comments

johnebaker wrote on 9/22/2017, 5:28 AM

VPX can export in many video formats, I would ask the FCP users what format they would like the video and audio to be and whether they should be separate files or video+audio combined.

Exporting to formats such as AVCHD, MP4, MPEG-2 involve compressing the video and audio, reducing quality.

For maximum quality export as Uncompressed AVI, however the down side is the file(s) will be massive.

. . . . . When I tried export a marked range, it still exported the full (uncut) project . . . . .

Did you check the Export selected range only option in the export dialog

HTH

John EB

emmrecs wrote on 9/22/2017, 5:41 AM

Hi Craig

If you want to export only the five minutes of video/audio and audio as separate tracks you first need to set a range which includes ONLY that part of the timeline. Then mute the audio only track and all other tracks. Go to File>Export movie> Video as ... (you will need to choose an export format that suits your workflow and to allow for further editing). On the Export screen ensure you tick "Export selected range only" (see image):

You will then need to unmute the audio only track and mute the video/audio track and all other tracks and repeat the procedure, this time selecting "... Audio as Wav".

HTH

Jeff

Craigster wrote on 9/23/2017, 3:12 PM

John and Jeff,

Thanks so much for the feedback.

Okay, so sure enough the "Export Selected Range only" works appropriately.

When I first tried to export to avi, 2 unexpected things happened:

1. The file size went from .57 GB/min (original AVCHD) to 50-fold, i.e. 22.5 GB! (5 min. file)

2. VLC warned of Index errors (which it can "fix" to play; but not actually fix).

So, then I exported to Raw-AVI (i.e. Uncompressed). These came out uncorrupted, but at a larger file size cost: 99x increase of file size: 55 GB (for 5 min file). So, we're talking 11GB/min at default settings!

Can anyone explain the relationship of original AVCHD file size & info to the codec used by default by Magix for the AVI container, which expands data 100x? I would expect "uncompressed" to simply not reduce the file. But the file increase seems absurd. Surely, it's not improving the video. Is this partly due to AVDHC already being a compressed format, which needs to then be uncompressed?

Actually, I'm now seeing on another forum post someone referencing the bit-rate Magix uses for it's AVI export. It is 145x the size of .mp4 export.

This all seems crazy to me. How 'bout 1:1 filesize: No compression. No expansion. Just accurate. What export option would provide this?

Then I exported via ProRes. (Apparently this is a newer form of the .MOV format. Windows isn't supposed to be using Quicktime anymore, according to Apple. So, is this the now-current form?)

Anyway, this worked (no corruption). Almost triple the filesize of original (1.5 GB/min). But 1/6 the size of raw AVI.

Does anyone know: Can you (should you) EDIT from ProRes .mov files?

Now I see the default for ProRes is HQ. There is also a QX option. Does anyone know the difference between HB and QX regarding less compression or higher bitrate (Advanced options is greyed out)? Again, my purpose is true quality video for external editing.

(My background is Audio. I would never add audio effects to a compressed format. I would always do editing at the highest resolution possible, i.e. 24 bit files within 32-bit float; not 16-bit, and surely not .mp3 or .aac files. So, this idea of passing on to a video editor compressed - yet larger - files makes me uncomfortable.)

Thanks for any additional input.

Craig

johnebaker wrote on 9/23/2017, 4:19 PM

. . . . Can anyone explain the relationship of original AVCHD file size & info to the codec used by default by Magix for the AVI container, which expands data 100x? . . . . Surely, it's not improving the video. . . .

There is no direct correlation between AVHCD file size and compression factor and an uncompressed version.

AVCHD uses an encoding algorithm (compression) that removes unnecessary data from the video file in such a way that the file size is reduced significantly and yet the quality is still acceptable when viewed, the amount of data removal depends on the scene characteristics eg if there is a high degree of movement, less data is removed compared to, for example, a sedate scene such as a slow pan across green fields and blue sky.

During playback the image is reconstructed from the compressed data with some slight loss of quality.

If you take an AVCHD (compressed) file, every single frame of the video is is reconstructed to full detail, and then saved without any compression hence the massive file.

The video is not improved, however it is not a good idea to decompress and recompress video, after a couple of cycles, the quality will start to go down hill rapidly.

. . . . How 'bout 1:1 filesize: No compression. No expansion. Just accurate. What export option would provide this? . . .

Uncompressed AVI - however you cannot get away from the simple fact that if you want no data loss then you will get massive file sizes.

Eg for 1920x 1080 30fps:

Frame file size = 2.1 MP (2,073,600 pixels)
Uncompressed RGB 8-bit frame: 6.22 MB* (2.1 MP x 24 bits)
1 min video file size at 30fps = 11GB

* note the units are Bytes (B) not bits (b)

IMHO you should export to the format and codec the FCP guys require, no matter what codec they require, you are not going to improve the quality of your source video from your cameras, which from what you said would infer they are AVCHD format.

HTH

John EB

Craigster wrote on 9/23/2017, 9:39 PM

Thank you, John.

Quite a learning curve here for formats, codecs, file sizes, etc.

Scenestealer wrote on 9/24/2017, 8:24 PM

Hi Craig

I think what you may be looking for is to export your AVCHD video material to AVCHD (Mpeg4 H264) using "Smart Render" or "Smart Copy" selectable in the advanced encoder settings from a VPX export template.

If your footage has only been hard cut from your original camera footage and has not been manipulated in VPX with effects etc., then Smart Copy will just copy frame for frame the selected range of clips to a new file with no degradation. If some of the clips in the range have been modified and some not, Smart Render will re-encode those frames only and copy the rest.

The trick is, to SR a sequence of clips the export settings / clip attributes must be more or less identical to the original in Codec, Resolution and Bitrate.

For SC this is not so important as it is copying all the attributes, but you need to be aware that it will not copy the cut point exactly so you may need to leave a bit of a "handle" of several frames at each end of each clips cut points.

SC can create audio offsets but as you are exporting the audio separately this will be synced in your next step in the post production chain.

Does anyone know: Can you (should you) EDIT from ProRes .mov files?

Yes - Prores is designed for it's ease of editing as an "Intermediate codec" ie with simpler / less (I frame only) compression (220Mbps for 422 HQ) but with very high quality possible (500Mbps for 4444XQ) for additional colour correction, compositing, etc .As John has pointed out, this would be pointless in your case because the information in the compressed H264 codec is not there to start with.

Peter

Craigster wrote on 9/25/2017, 12:42 AM

Ah, thank you so much, Peter. I will have to experiment with Smart Render and perhaps Smart Copy.

Can you elaborate regarding ProRes... Are you saying that the higher resolution of QX (as compared to HQ) would be pointless to me when starting with original AVCHD footage (MTS files)? Or or you saying thst even exporting as ProRes (mov) HQ is pointless?

My concern is to not degrade the original footage (via compression prior to final rendering) to MP4 or MPEG variants, but to preserve the original quality as much as possible (without increasing filesize 100-fold), until ready to render for final viewing.

Craig

Scenestealer wrote on 9/26/2017, 2:11 AM

Hi Craig

Rule 1 is to avoid transcoding or re-encoding of compressed formats during the post production chain as John EB has mentioned, so based on that and the fact that you may not know the final delivery files format or the additional processing that may be carried out by the next guy, I would say use the Smart Copy option.

If you do need to re-encode AVCHD H264 even at the same settings that match your camcorders file specification settings I would use the ProRes 4.2.2HQ template in VPX which is described by Apple as visually Lossless when compared to Uncompressed AVI. I have tested this with H264 transcodes in VPX and found it to be so but at the expense of an increase of file size of about 10x that of H264.

It is not so much that there are advantages in ProRes HQ in terms of colour detail etc. because as I mentioned earlier this can not be created from the 4.2.0 colour sampling of AVCHD, but it is that any re-encode in VPX of this compressed format always degrades fine detail in darker low contrast areas. This I suggest is because of the Psycho Visual algorithms built into H264 compression that save bits by not faithfully encoding all the detail in areas where it thinks you might not notice, much the same as the Psycho Acoustic algorithms in mp3 or AC3 compression.

As you are handing this footage on to an Apple environment the Prores should work well (assuming the next editor has a powerful system) and has the added benefit that you could consider adding your synced hi quality audio to the encode which will be output in PCM 1536kbs Stereo as part of the Prores MOV.

The reason I say powerful system is that AVCHD H264 uses a lot less CPU during preview than ProRes, despite Prores being less compressed and intra frame, because H264 decompression necessary for playback is assisted by Hardware Acceleration via the GPU on modern systems. On my system H264 uses about 6% of the CPU, on the same file after conversion to ProRes it uses 90%!

Peter