MP4 Help

[twinaleblood]

Hi everybody, I have a sort of newbie question, hope someone can help.
I used to shot shows with a Samsung MiniDV cam. I used to transfer them on my pc through firewire port and dvdlab pro 2 has always been my choice to do the authoring thing.

Now I got a new Samsung as Xmas gift and it saves the footage in MP4 format (720x576) on a SD HC flash card, but mp4 files are not compatible with dvdlab. How can I author them?

Cheers.

[peaktime]

I'm sure there are programs that will do the conversion from mpeg4 to mpeg2 so you can author a dvd, such as tmpgenc xpress, but you will lose quality, and blow up the size a lot. Mpeg2 and dvds was the old way, but now mpeg4 and blu-rays are the new way. Mpeg4 compresses smaller and with higher quality than mpeg2. For the best quality, author a blu-ray directly from the mp4 (don't re-encode), or just seed the raw mp4 if they will let you. There are a number of different blu-ray authoring programs available.

[twinaleblood]

Yeah, but doesn't a blu ray have a higher resolution than a dvd?
These mp4 files are 720x576 and I think this is the resolution of a standard pal dvd, isn't it?

[peaktime]

Blu-ray can use standard definition resolution as well.


If you ever want to use a different audio source and still use the original video, you can demux the mp4 with Yamb (yet another mp4box) GUI, and then sync the new audio to the old audio in Vegas or similar and render as wav. For lossless, you can then convert to FLAC and add this FLAC and the .h264 file to mkvmergegui and use the mkv format. Both programs are free. Or you should be able to add the separate audio and video streams to a blu-ray authoring program.

[twinaleblood]

Thank you very much, Peaktime. Your answers seem very helpful!

[paddington]

Originally Posted by twinaleblood

Yeah, but doesn't a blu ray have a higher resolution than a dvd?
These mp4 files are 720x576 and I think this is the resolution of a standard pal dvd, isn't it?

PAL, yes.. but NTSC DVD is 720 x 480... not 576. You are already higher-res than an NTSC DVD, but it's a non-standard hieight (though 576 is supported by the h.264 codec). Encode to h.264 (which it may already be, inside the MP4 "wrapper"), profile 3.

You may wish to crop it or something.. 720x576, a 1.25:1 aspect ratio, is a bit square in this day of 16:9 ratios. normal DVD is 720x480, which is 1.5:1 (3:2).

the old NTSC TV ratio of 1.33:1 (320 x 240 - 4:3) was fairly square, so your 1.25:1 is going to look really square and won't "fill" any standard display with aspect ratio preserved, other than maybe the one on your camera or something.

[peaktime]

http://en.wikipedia.org/wiki/Pixel_a..._video_formats

PAL uses wider, more rectangular pixels than NTSC though, so you can't really compare the aspect ratios based on number of pixels.

Pixel Aspect Ratios:

Standard 4:3 PAL: 1.09
Widescreen 16:9 PAL: 1.45
Standard 4:3 NTSC: 0.90
Widescreen 16:9 NTSC: 1.21

Square pixels are used in most high definition formats though.

[peaktime]

if you take the aspect ratios based on pixels and multiply by their pixel aspect ratios, both systems have the same aspect ratio. (the final numbers should be closer but these were done using rounded numbers)

NTSC Standard: 720 / 480 = 1.5 x .9 = 1.35

NTSC Widescreen: 720 / 480 = 1.5 x 1.21 = 1.815

PAL Standard: 720 / 576 = 1.25 x 1.09 = 1.3625

PAL Widescreen: 720 / 576 = 1.25 x 1.45 = 1.8125