Basic question about scenario Converter > VirtualDub > Converter

[XenonS]

Hi,
I currently use the 2 video editors VSCD Free Video Editor and VirtualDub + 200 filters (32bit) for special operations. My original videos are in MP4 format, encoded in H264 codec, 600 bitrate.
If I want to make editions in VD I have to convert them in AVI format before, make my work in VD and then - for filesize reasons - re-encode them back with the H264, or keeping the Xvid MPEG4 encoding from VD and put them down to a birate of 600-700.

I'm concerned about quality loss in these operations above, just with eyeball I can see some 'undesirable wave effects' if I open the final video with Windows Media Player and looking at frames with blue sky. These 'waves' were not in the original; however if I play this vid on TV it's perfect.

My question is:

a)
Before editing in VirtualDub, I could convert my original videos in Lossless format chosing AVI container + PNG lossless encoder or Lagarith lossless. The output files would be really huge, but it's just temporary unitl I convert back again. Is this a good idea to avoid quality loss?

OR:

b)
I could just not care about lossless formats and just build a decent AVI file at a target bitrate of 1600, send it to VD to fine-work, once finished editing I chose the Xvid MPEG4 encoder with a target bitrate of 1600 (1-pass), export the AVI file and convert it back by chosing the same encoder but putting it down to a target bitrate of 600-700.

Which of the 2 a) or b) is better? Is one clearly wrong if you want to keep quality?

Thanks very much for your answers,
Greetings,
XenonS

[jagabo]

Why don't you just open your MP4 file in VirtualDub? There are a few source filters and VFW decoders that allow that.

[XenonS]

Hi jagabo, yes, in fact i have downloaded such a plugin called "VirtualdubFFMpegPlugin_1836.zip" and unzziped it in the Plugins32 folder of VD.
I'm able to open in MP4 now, but still there is no H264 encoder for the output, so I will have to chose the Xvid MPEG4 encoder. The result is not very good, that's why I'm asking above about using lossless formats first before going into VirtualDub. Using these formats, will this matter for the quality output or not?

[EDIT]
A reason why I don't want to open in MP4 in VirtualDub is because I cannot append other files (which is possible only in AVI format) to treat a single file from a serie of files.

XenonS

[jagabo]

Hi jagabo, yes, in fact i have downloaded such a plugin called "VirtualdubFFMpegPlugin_1836.zip" and unzziped it in the Plugins32 folder of VD.
I'm able to open in MP4 now, but still there is no H264 encoder for the output, so I will have to chose the Xvid MPEG4 encoder. The result is not very good, that's why I'm asking above about using lossless formats first before going into VirtualDub.

That makes no sense. If you can open the MP4 files directly in VirtualDub why would you need to convert to a lossless video first? That's a waste of time and disk space. Well, not always. Sometimes you may experience seek problems with h.264 sources. In that case converting to a lossless intra frame intermediate first will help.

You can use x264vfw for h.264 output directly from VirtualDub. You can also output to MP4 or MKV using the output plugins.

Using these formats, will this matter for the quality output or not?

lossy encoding always looses some quality. So yes, using a lossless intermediate will result in less quality loss than using lossy intermediates. But opening the source directly will give the same quality as using a lossless intermediate (seek problems aside).

[XenonS]

Thanks jagabo, so opening in MP4 and also saving in MP4 is of course the better thing, I didn't think this was possible. Thx to point me to this output plugin.
The less converting you do, obviously the less problems you run into

Cheers,
XenonS

[XenonS]

Humm...It seemed all clear, but unfortunately not yet for me:

You can also output to MP4 or MKV using the output plugins.

By googling for some possible 'output plugins' for VirtualDub, AFAIK you can import MP4, but you have to export in AVI, so what's the sense in opening in MP4 in the first place ??
I have found 2 posts with some 'voodoo' methods to export MP4, but I'm not sure if it's related. One post is here:

https://forum.videohelp.com/threads/368314-Merge-mp4-files-without-reencoding-with-Virtualdub

... and the 2nd here:

http://superuser.com/questions/43588/how-can-i-merge-two-mp4-files-without-losing-quality

The command to export to MP4, if I understand it right, would be this (I'm quoting the content in the 2nd link):

-------------------------------------
(...)

"You can do this with ffmpeg:"

mkfifo temp0 temp1
ffmpeg -i input0.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts -y temp0 2> /dev/null & \
ffmpeg -i input1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts -y temp1 2> /dev/null & \
ffmpeg -f mpegts -i "concat:temp0|temp1" -c copy -absf aac_adtstoasc output.mp4


"This doesn't re-encode anything, it places them in a new transport stream container, which makes them more easy to concatenate, and then concatenates them back into an MP4. If output.mp4 already exists, the command will fail. The version above uses named pipes, if you're on a system that doesn't support those you'd have to use intermediate files (like windows):"

ffmpeg -i input0.mp4 -c copy -bsf:v h264_mp4toannexb temp0.ts
ffmpeg -i input1.mp4 -c copy -bsf:v h264_mp4toannexb temp1.ts
ffmpeg -i "concat:temp0.ts|temp1.ts" -c copy -bsf:a aac_adtstoasc output.mp4
(...)
-------------------------------------

This is total chinese for me... Is such a scnenario possible from VirtualDub? Alghough I have the ffmpeg plugin (see my answer above), I don't see any ffmpeg in the 'Conversion' list, only a new H264 option to chose from.

So: Is it possible to export to MP4 from VirtualDub?

Thank you

XenonS

[jagabo]

https://forum.videohelp.com/threads/367446-Virtualdub-External-Encoder-feature

[XenonS]

Thanks again, jagabo for your input. Your link implies a lot of apps to download and use (and also reading notes to be able to understand them), this is moving the waters a lot for just allowing VD to export as mp4...
What about the alternative to use the Export > Export Raw Video ? Apart the temporary huge file size output, I could then re-encode my work in VSCD Free Editor.

XenonS

[jagabo]

I doubt VSCD will handle raw video -- that's a containerless uncompressed video stream. What you want is uncompressed AVI, losslessly compressed AVI, or compressed AVI. File -> Save as AVI.

[XenonS]

yeah, I just realize it
I think what you suggest here is the best solution if I export to AVI from VirtualDub.

There are also new complications: I have to work on 5 different mp4 files from the same video, but I realize now that they cannot be joined because slightly different (the 16:9 aspect does only appear in the first one and not in the others), I tried to join them with MP4Tools, but nada, the result is trash and will only play audio. So I have to work on the 5 files separately.

What I will try as an alternative is:

I will open mp4 in VD (possible because plugin installed), edit and encode in Compression > x264vfw; I set the average bitrate to 800 AVR and chosing the VirtualDub Hack checkbox (for not losing any frames) and export to AVI. In VSCD Free Editor I will then convert to MP4 chosing the same encoder but the Target Bitrate at 700, so this will in the worst-case only downsample the video - and hopefuly give a decent quality.

With your help I now have all the info I need, thank you very much for taking your time

Greets,
XenonS

[jagabo]

If you're going to recompress with VSCD I would suggest exporting from VirtualDub at CRF 12 or lower, with short GOPs, and no bframes. Even better, encode with VirtualDub at your desired birate and settings then just append all the resulting files and mux into MP4. If you're going to do it that way don't use the VirtualDub hack.

[XenonS]

I have just made a test with an AVI exported video in the Lagarith Lossless format; this encoding is surprisingly fast. Then, I converted it to MP4 in VSCD at a target bitrate of 700 with the encoder named "H.264 / AVC (Advanced Video Coding)". For testing purposes, I then converted the same AVI file using the free version of Any Video Converter. Here the codec is named "x264". I also set this to 700 bitrate. Both ouput MP4 files, the VSCD and AVC are 60mb of size. When I open both files with Windows Media Player it turns out that the AVC video is far superior in quality.

Were the encoders the same? If not, this may explain the quality difference, but I doubt somehow.

I'm very disappointed because VSDC has the perfect interface for handling videos IMO and one of the rare free tools where you can edit and output more different videos at the same time. But all this doesn't count if ouput videos are of bad quality. I still hope that I'm wrong here, and I will try to play with the Profile settings, alas by changing them chances are the results will be even worse.
Also no replies from the VSDC support after feedback on their website.

[jagabo]

h.264/AVC is the specification. x264 is an open source implementation of the h.264 spec. I don't know what VSDC uses for h.264 encoding but most free programs use x264. MediaInfo may show you what encoder and settings were used (x264 puts its encoding parameters in the metadata). There are dozens of settings in x264 that effect encoding speed and quality.