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xarmarelena
7th March 2002, 19:00
Originally posted by DSPguru
3) AC3->MP3. which AC3 stream should i decode ? 5.1 or 2.0 ?
the 2.0 stream has a better mix for 2 channels (stereo), than the 5.1 to 2.0 downmix features offered by AC3 decoding tools. therefore, it should be the best to work with the 2.0 stream.
there is only one case when transcoding the 5.1 stream is better :
if your computer has connection to a dolby pro-logic decoder, you could use a surround downmix, and then your dolby pro-logic decoder would reconstruct the multichannel audio.

4) How to extract 2nd audio track from AVI?
1. Open the file in NanDub
2. Set primary audio stream to "No audio"
3. Set secondary audio stream to "AVI audio" and check "Direct stream copy"
4. Set video to "Direct stream copy"
5. Select "save as AVI"

this should simply delete the first audio track from the file, which leaves you with a file with 1 video and 1 audio track (the secondary from the original file). Than you can extract this audio track.

Sibe

5) I have an AVI with AC3, but i hear no sound. what should i do ?
install the AudioFilters from doom9's download page (http://doom9.org/software2.htm#filters).
if this still doesn't work, try to remove the 'morgan stream switcher'.

6) how do i change the samplerate of wavefile into 44.1khz ?
download ssrc from doom9's download page (http://doom9.org/software2.htm#audio), and use the following command :
ssrc --rate 44100 input.wav output.wav
7) how can i join ac3 files ?
let's say you want to join stream1.ac3,stream2.ac3,stream3.ac3 into stream.ac3.
create a listfile. join.lst :
stream1.ac3
stream2.ac3
stream3.ac3

and then, use BeSweet :
BeSweet -core( -input join.lst -output stream.ac3 -payload )
this will also work on CBR mp3 files.

8) what's CBR/ABR/VBR ?
CBR means that the stream's bitrate is constant and never changes.
VBR means that the stream's bitrate is variable, and changes in according to the amount of info that needed to be encoded.
ABR has a variable bitrate for each frame, but its average bitrate is a constant.

conclusion :
CBR is a private-case of ABR which is a private-case of VBR.

9) why would i want to encode mp2 audio rather than mp3 ?
most vcd systems won't play mp3, so if you plan to create vcd, you should encode into mp2.

10) can i backup music from a concert dvd into an audio cd ?
yes, checkout BeSure from doom9's download page (http://doom9.org/software2.htm#audio).

11) I'm playbacking a divx with ac3, volume is too low. what can i do?
download DeDynamic from doom9's download page (http://doom9.org/software2.htm#audio).

12) what's the difference between stereo, joint stereo & dual channel ?
dual channel - 2x mono-channels. meaning each channel is encoded with half the bitrate of the overall bitrate.
stereo - 2 seperate channels, but the bitrate allocation between those two channels changes accordingly to the amount of info there is in each channel.
joint stereo - 2 channels, but takes advantage of what is common between the channels, so the compression gain is higher.

13) how can i convert ac3 stream into mpeg2multichannel stream ?
you would need the phillips encoder (http://www.licensing.philips.com/ordering/soft/documents343.html), and BeSweet v1.2 (http://DSPguru.doom9.org).
here are the two commandlines :
BeSweet -core( -input input.ac3 -output inter.aif -6chaiff ) -ssrc( --rate 44100 ) -ota( -g max )
pub_enc -l 2 -m s -n d -r 44.1 -b 384 -L -p 3 -e -v 0 inter.aif final
the result file will be final.mpg which is a mpeg2multichannel stream.

14) can i raise up the volume of a mp3 without doing decode,normalize,encode ?
yes, there are few programs that offers this, check mp3gain (http://www.geocities.com/mp3gain/) & mp3trim (http://www.logiccell.com/~mp3trim/) for instance.

How can i convert mpeg(video clip) to mp3 or other formats like wav ?
xarmarelena

i have allready ask for help but nothning....

damjang
8th March 2002, 09:29
Originally posted by xarmarelena


How can i convert mpeg(video clip) to mp3 or other formats like wav ?
xarmarelena

i have allready ask for help but nothning....

You must specify what type of video mpeg:
1) mpeg2 (DVD) that can contain ac3, pcm, or other audio tracks
2) mpeg1 that contain mpeg audio track

Look at doom9.net guides!

damjang

MaTTeR
8th March 2002, 17:28
This thread has been viewed 3776 times. Wow!

How can i convert mpeg(video clip) to mp3 or other formats like wav ?
This question is asking how to convert a video format to an audio format:D This obviously can't be done. Perhaps you mean something else, so please be more specific.

xarmarelena
9th March 2002, 13:21
Originally posted by MaTTeR
This thread has been viewed 3776 times. Wow!


This question is asking how to convert a video format to an audio format:D This obviously can't be done. Perhaps you mean something else, so please be more specific.

Someone gave me a cd with 13 video clips.
These video clips are mpeg.
I want to take the sound of these video clips
and make them mp3 or wav.

1)How can i find what type of mpeg they are ?

2)Most files of them are mpg(Movie file) but 2 files
are asf.What kind o format is this.

I use DVD2AVI and BeSweetGui to make mp3 from DVD´s.
It works perfect.

Thank you for your help.

Chrisochoou Charis - Drama - Greece

MaTTeR
9th March 2002, 16:16
@xarmarelena

I've never tried but you can have a look here- http://forum.doom9.org/showthread.php?s=&threadid=7633

Notice the very last post of the FAQ.

damjang
11th March 2002, 09:15
Originally posted by xarmarelena
Someone gave me a cd with 13 video clips.
These video clips are mpeg.
I want to take the sound of these video clips and make them mp3 or wav.
1)How can i find what type of mpeg they are ?
2)Most files of them are mpg(Movie file) but 2 files are asf.What kind o format is this.

I use DVD2AVI and BeSweetGui to make mp3 from DVD´s.
It works perfect.


1) play the files in mplayer2.exe (windows media player 6.4) and go in properties menu. In the section with all the filters listed go in properties of the mpeg video decoder...
2) I'm not very shure but I think that this file is one type of windows media video.

hope this help
damjang