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nessusing
10th February 2005, 19:35
Hi, this is my first post here and i am still new to video/audio compression, so some of the terms i use below may not be exact, plz bear with me, thx!

Basically my problem is: by given a xvid and VBR mp3 encoded dvdrip, i want to downgrade it in order to play it on my cell phone. since my cell phone has a xvid supported player, so all i really need to do is just making the source video at a lower bitrate.

3 actions i need to do: resize(my cell phone wouldn't allow playing a video with size bigger than the cell phone's physical screen size), lower bitrate of video, lower bitrate of audio.

tool: VirtualDuB1.6.3
First trial: Doing all above actions at once, it turned out that video and audio mismatched(video delay).

Second trial: extract mp3 first, decompress it back to wav. then do resizing, video/audio compressing at once again, but still mismatched.

Thired trial: resize first, then compress the resized video and wav. this time it work!

so my question is: is this the best way to do it? it seems to me this is so complicated, and there must be a better and eaiser way to do this. if i have to do these separtely and manually, it would be impossible to make this in batch mode since i really want batch produce 4~5 movies over night.

sorry about my terminology again, i did best i could;)

nessusing
10th February 2005, 23:14
well i guess i will just have to use the old traditional way -- sync manually by going into interleave in virtualdub and it actually worked ok!

Mentalmummy
11th February 2005, 01:29
You can use VirtualDub to adjust the framerate and resize the video, also to compress the audio to a lower bitrate.

I`ve got an xvid player on my ngage and if I remember correctly it was fine with 90 to 100 Kbps as a bitrate for video, obviously audio will be lower quality and probably mono.

A lot of phones will not play a full framerate xvid smoothly, it is still common to have a framerate for phones of 12 or 15 frames per second. You can also use VirtualDub to decimate frames.

You might find your best option is to use VirtualDubs video filters to add a resize to the appropriate size of your phone and adjust the framerate if it is over 20 frames per second.

Then save as a new xvid file without gmc and qpel active.

Dave

nessusing
11th February 2005, 02:12
Thanks alot Mentalmummy. I did search again in the forum, and noticed that the framerate for playback at handheld devices. However, i think the audio sync problem definitely has something to do with the nonstandard VBR MP3 encoding. Becuase I've converted another movie with AC3 audio just fine!

I guess the ultimate way to sync a audio is using interleave in VD if every else way fails. i know this solution wont give you the exact result, cuz u need to use you eyes and ears to do the adjustment, however it always works! and i am ok with. after all, i am just watching it on my cell phone!!

HAPPY!! and thx again!!