digitalFAQ.com Forums [Archives] - Using ffdshow/libavcodec to decode Mpeg-4

digitalFAQ.com Forums [Archives] (http://www.digitalfaq.com/archives/)

- Video Encoding and Conversion (http://www.digitalfaq.com/archives/encode/)

- - Using ffdshow/libavcodec to decode Mpeg-4 (http://www.digitalfaq.com/archives/encode/14141-ffdshow-libavcodec-decode.html)

sparskter

03-01-2006 04:30 PM

Using ffdshow/libavcodec to decode Mpeg-4

Well, everyone says that using libavcodec to ENCODE @ MPEG-2 is not so good. So, what about using ffdshow to decode Videos[MPEG-2/MPEG-4/etc]/Audios[MP3/OGG/etc] to then encode @ any mpeg-2 encoder ?

I am asking this, because I had a serious problem with ffdshow. An avi of MEGAMAN X8 [http://www.speeddemosarchive.com] was not encoding until finish. I tried to uninstall ffdshow, using xvid instead and it worked :!:

Bad luck ? :D

kwag	03-01-2006 05:57 PM

Re: Using ffdshow/libavcodec to decode Mpeg-4

Quote:

Originally Posted by sparskter

Well, everyone says that using libavcodec to ENCODE @ MPEG-2 is not so good. So, what about using ffdshow to decode Videos[MPEG-2/MPEG-4/etc]/Audios[MP3/OGG/etc] to then encode @ any mpeg-2 encoder ?

Every re-encode is another generation of quality loss.
Don't do that :!:

-kwag

sparskter

03-01-2006 07:20 PM

Code:

LOADPLUGIN("D:\filters\fdecimate101\FDecimate.DLL")

AviSource("D:\[PS2]MegaManX8_100p_236_[PS2].avi")

RESAMPLEAUDIO(48000)

CONVERTAUDIOTO16BIT

FDECIMATE(23.976)

CONVERTTOYV12

Lanczos4Resize(304,208,16,7,290,218)

Addborders(24,16,24,16)

I am using this script above. And then I use it on HC encoder. I think ffdshow is only decoding my avi/mpeg-4 file.

Is this a re-encode ?

kwag	03-01-2006 08:33 PM

You are "decoding" an AVI, to then "re-encode" (once again!) witn HC in this case.
So you are loosing quality by decoding and encoding again.

-kwag

sparskter

03-01-2006 09:03 PM

8O

How should I process that .avs file ? The avi is original from http://speeddemosarchive.com

I simply opened it on Paranoia and then added some extra-commands. Nad then I open it (.avs) on HC encoder. There is other way ?

Dialhot

03-02-2006 05:13 AM

I think Karl read your first question in a wrong way.

Basically you are just asking "what about using FFDShow as a generic decoder to open any kind of source in avisynth". And the answer is in your first post : the experiment shows that this is not a good idea !

FFDShow does a lot a things, but never do them as good as the original codec. If possible, use the original (Xvid in your initial post).