Aspect Ratio When Played on a Computer Directly Plugged into a TV

[dcabiness]

Hi, I'm encoding episodes of TV series from DVDs I've ripped to H.264 .mp4 files using the x264 encoder. I watch the episodes on my TV, but they are being played from my Mac Mini which is directly plugged into the TV.

I know that if you plan on watching the video on your TV, leave the dimensions as 720x480, but if you want to watch them on your PC, change them to 640x480. Since I'm watching them on a TV, I left the dimensions like the original.

Then, I noticed my encoded video was a different shape than the original! I was unsure what to do at first, but I had an idea. I changed the screen resolution to 720x480 and sure enough, my encoded video played full screen and the DVD had black bars on it. I changed the screen resolution to 640x480 and the DVD played full screen and my encoded video had black bars.

My only conclusion is that my Mac Mini is altering the shape of the DVD, but not the shape of my encoded video. Therefore, I ought to encode my videos at 640x480 regardless weather my Mini's monitor is a TV or not. Am I right?

P.S. - If your wondering how I can deal with having a TV as a monitor, its because I use my laptop and a VNC client to remotely control my Mini. Also, the mini has a remote control for pausing and fast forwarding and the like.

[DJRumpy]

There is no reason to change the file's resolution for playback on a PC unless the source used an embedded aspect ratio and your converting it to a format that doesn't support embedded aspect ratio's.

Chances are you Mac media player isn't properly detecting or enforcing the display aspect ratio on your ripped DVD's.

Is your source video still in DVD format when your playing it back?
What format are you converting it to?

[dcabiness]

When I reread my post, I realized I worded the first sentence a little oddly, so let me rephrase it. I have store bought DVDs with TV episodes on them. I ripped each episode off the DVD to their own .VOB file. Then I used ffmpegX and the x264 encoder to encode them as H.264 .mp4 files.

I'm playing the .VOB using VLC and it shows as 640x480, but ffmpegX says that same file is 720x480. When I encode the episode as 640x480, it plays full screen just like the original. So that is the way I will continue encoding them and future disks.

My only confusion was (and still is) that the DVD is playing full screen when a .mp4 video with the same dimensions does not. My mini must internally alter the shape of my DVD (and ripped .VOB files) to fit the screen, but not other files.

[jagabo]

VOB files contain display aspect ratio information that tells the player at what aspect ratio to display the video. For example, a VOB can have a frame size of 352x480 and include a DAR flag indicating it should be played with a 4:3 display aspect ratio. Note that 720x480 is not a 4:3 ratio so your VOB includes this flag.

MP4 files also support DAR flags but your encoder may not be setting it, or the player may be ignoring it. In the absense of a DAR flag (or DAR flag handling by the player) a 720x480 video will not fill a 4:3 screen, whereas a 640x480 video will because the frame size is a 4:3 ratio.

So you need to verify that the DAR flag is being set by the encoder and that the player respects it. Otherwise you should convert to a 4:3 frame size.