Custom Video Resolutions

[Jim Pickles]

I hope it is OK to add a new query to this existing thread. I have a lot of old .mpg (720x576) videos saved, which I would like to convert to mp4 format at the same resolution to save space. I'd like to stick with the original source resolution because otherwise artefacts are introduced into the video. However if I go to VideoStudio X9 Settings > Movie Profile Manager > Format MPEG-4 and try to add a new profile (or edit one of the existing Personal Profiles) > General > Frame size I am confined to standard ones and the User-defined option is greyed-out (even if I alter Display aspect ratio to 4:3). Do user-defined options exist and how do we get access to them? Or is 720x576 somehow forbidden for MPEG-4? I looked through the thread above and did not see a solution.

Many thanks, Jim.

[asik1]

Jim, If you change the mp4 compression to M4V (H263) you will have that resolution.
For H264 codec, deep advanced tweaking is needed, but I don't see any advantages for that SD footage.

[lata]

Hi Jim
First I doubt converting to MP4 is gonna save you space and probably not worth the effort

Mpeg2 720 x 576 is Pal format being anamorphic it could be 4:3 or 16:9
720 x 576 may not be 4:3 that frame size is stretched to create either 16:9 or 4:3 (4:3 effectively just to confuse would be 768 x 576)
The frame size does not affect the files size that much, the data rate in kbps affects the files sizes.
For Mpeg2 at 8000kbps will create a video at 4 Gb per hour.

More important I would think is the interlacing, I suspect your Mpeg2 uses Lower Field first.
You should try to retain that option, changing the interlacing can affect the quality although it could be Frame Based ?

I ran a quick test comparing top quality Mpeg2 one minute was 22Mb to Mpeg4 17Mb, the Mpeg4 was used low quality settings. a second test gave 25mb so was larger than the Mpeg2?

I used these settings:-
MPEG-4 Files
24 bits, 720 x 480, 25 fps
Lower Field First
H.264 High Profile Video: 2500 Kbps, 4:3
48000 Hz, 16 Bit, Stereo
MPEG AAC Audio: 160 Kbps

Using M4V as Asik suggests created a file at 16Mb but squashed the video a little (small border left and right) as its not anamorphic, creating a true 720 x 576 frame. Also used Frame Based

MPEG-4 Files
24 bits, 720 x 576, 25 fps
Frame-based
MPEG-4 ASP Video: 2000 Kbps
48000 Hz, 16 Bit, Stereo
MPEG AAC Audio: 160 Kbps

If you are to continue to convert your mpeg2 files then you should do a few tests to see what options are best. Comparing interlacing, frame size and file size, is it worth doing?

[Jim Pickles]

Many thanks for those replies. Trevor - I have been trying your options. The problem was indeed the interlacing (I thought that had gone out with the ark, but some of these videos are a bit - 12 years - old). Setting the output to interlaced solved the quality issues I had been getting with MP4 outputs.

My reasons for doing this: I was hoping to take advantage of the greater efficiency of MP4 compression compared with MPG. I had also been compressing videos with Handbrake and found that 2 Mbps for a MP4 720 video often gave quite acceptable results, so started saving a lot of my archived videos at that data rate. The data rates of my original MPG files are around 5-6 Mbps, so with MP4 I can make files nearly 70% smaller. Next I thought if I made the videos at the original resolution rather than 1280x720 it would make them even smaller without loss of quality, while getting rid of the artefacts that I'd been seeing. Actually, using MP4 720x480 at 2 Mbps gave notably worse-looking output than 1280x720 at practically the same data rate.

The problem was indeed the interlacing, and as 720i gives just as good images as the original MPG (while giving files 30-40% of the size) I'll stick with that. So many thanks for your input. Also, I hadnt realised that 720x576 was anamorphic.

I guess now I need a way of objectively measuring the quality of the output, rather than just going by my tired old eyes.
Many thanks indeed for your help,
Jim.

[aljimenez]

I recently did this to my huge collection of video movies. Many were .mpg and .avi with non standard resolutions that do not play with my new ROKU streamer. I used Format Factory for the conversion. Not only did this program worked well and fast, all the new .mp4 files were much smaller in file size; some .mpg files ended up being 60% of the size in the .mp4 version. The quality was perfect by the way.

Thus my recommendation is to do this with Format Factory, which I have no financial nor any relationship with and the program is free.