Questions and a possible bug with MOV mpeg4 preset

[sirlethean]

Hiyas, my two days of waiting are finally over so I can post now. I have an AVI that uses Xvid that I'm trying to convert to MOV mpeg4. (It's captured video from a video game and I'm just playing around with ffmpegX basically.)

My first problem was that I kept getting a corrupt MOV file. The video wouldn't play in Quicktime (said I was missing a codec), and mplayer wouldn't play it because of errors. Using trial and error, I finally figured out what the problem was. When I was getting the corrupted MOV files, I had "Use B-frames" checked. When I do the exactly same options, only unchecking the B-frames option, I get a good MOV file. So apparantly there is a bug with the ffmpeg encoder or something (or that option isn't valid ).

Once I got that figured out (the results were awesome btw), I ran into another weird problem. The original video is at a resolution of 800x410 -- weird I know. No matter what i do, I can't get my new movie at the same resolution. If I create an AVI with the mencoder encoder, it makes an 800x410 movie just fine. When I try to make a MOV using the ffmpeg encoder, it seems to just ignore it. I saw on the online manual that some codecs have problems with resolutions that are not divisable by 16, so I tried making it 800x400 by cropping off 6 pixels from the top and 4 from the bottom. I ended up with a video with the resolution of 711x400. I'm not touching the autosize button at all, just changing the resolution, which is what I did when using mencoder and it works just fine. Help?

Another question I have is encoding this to DVD. I want it to have all the proper letterboxing, etc. on both 16:9 and 4:3 tvs. For the size should I pick DVD or DVD 16:9? For the letterboxing should I check "Decode with Quicktime" and then the "Letterbox" checkbox? My biggest question is the difference between the DVD and DVD 16:9 settings.

Thanks for taking the time reading this, I searched the board while waiting to post, and I couldn't find answers to these specific questions/problems. Thanks!

[major]

1/ There is no bug, it is a Quicktime issue. MOV mpeg-4 uses the native mpeg-4 Quicktime decoder instead of requiring you to install DivX or 3ivX codecs.

2/ The true size is the one which is displayed in the left LCD screen of ffmpegX when you open the file. Quicktime Player often apply an aspect correction and shows a wrong size.

3/ The difference between DVD and DVD 16:9 is that in the second case a 16:9 image is mapped into a 4:3 one, so less bits are wasted to encode black bars, and at playback it is mapped back to 16:9.

[Flarch]

1/ There is no bug, it is a Quicktime issue. MOV mpeg-4 uses the native mpeg-4 Quicktime decoder instead of requiring you to install DivX or 3ivX codecs.

Meaning for complete compatability with QuickTime B frames are a no-no?

I transcoded a video to MOV mpeg 4 and it played with mplayer. Quicktime won't play it. I may have had B frames turned on.

[major]

Yes, for native compatibility with Quicktime of the "MOV MPEG-4" preset, b-frames and qpel must not be used.

[spiderlegs]

What about sound? I have an m2v and an ac3 file I simply mutliplexed into an mpg and Quicktime won't open it. It opens fine in mplayer, and VLC can't get sound. B-frames weren't selected.

So, I encoded it to an .mov file, and it will open in Quicktime, but without sound. Mplayer can't get any sound, either.

For QT Pro 6.5.2, I have the 3ivx D4 4.5.1 for OSX, ACS Codec.component, QY v.6 MPeg2 plug_in, vvid codec v.0.5.component, xviddelegate.component. But, no matter what "Mov" setting I use, I get no sound and occasionally, the file won't even open.

Obviously, I am totally new at this, so I'm sure it's a setting I've missed, but I've read and referenced the manual twice in trying to get this right. I appreciate your advice.

Also, this is on my work system, a G5 running OS10.3.8, not on my home system which is listed under my profile.

[major]

Send me the encoding process output (click the blue "i" icon in the progress window) to major4@mac.com

[spiderlegs]

Email sent. But my problem is with Mpeg2, not mpeg4 like the topic says. I hope that didn't mislead the topic.

[monkeyhouse]

2/ The true size is the one which is displayed in the left LCD screen of ffmpegX when you open the file. Quicktime Player often apply an aspect correction and shows a wrong size.

So what is the work around for this problem?

I've got DV footage that I've converted to Quicktime (.mov) format using ffmpegX. The DV's native resolution is 720x480 (3:2) and, as was pointed out, ffmpegX confirms the resolution has been retained in the converted .mov (in the left LCD screen), but it displays as 640x480 in the Quicktime player, due to this aspect correction I presume.

Just a thought, as I wrote this, is it the 3:2 aspect ratio QT doesn't like, so converts it to 4:3?

Just to add, if I open the DV file in QT, it retains and displays the 720x480 resolution and it still does if I convert it to a .mov in QT too. So confusing.

[major]

720x480 is not 3:2, as the pixels are not square. QT correctly converts to 640x480 square pixel 4:3.

[monkeyhouse]

Errr... ok... so how do I create a file with ffmpegX that doesn't get distorted by QT? And why would QT Pro and ffmpegX creat something different? i.e. QT Pro can produce a 720x480 Mov from my DV file and display at that resolution too, but the file created from ffmpegX is displayed at 640x480 and therefore distorted.

How come my DV footage is not at 4:3 in the first place? I use iMovie to import the footage from the video camera and 'share' to a full quality DV file and import that into ffmpegX/Quicktime Pro.

Thanks for the fast reply though, the help is appreciated!

[major]

The DV footage is meant to be displayed on a TV screen, where pixels are not square, so as 720x480 is 4:3. If you display it on a computer screen, where pixels are square, a correction is needed to keep the same aspect ratio, and display circles as circles. You may overcome the Quicktime Player correction by going into the Quicktime Player prefs (apple-J, video track, size, shift-resize.

[monkeyhouse]

Thank you, thank you.

I found more info here too https://www.videohelp.com/forum/viewtopic.php?t=244151