IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
ripping audio from AV files, to avoid transcoding of audio data
raygrote
post Jan 3 2012, 00:10
Post #1





Group: Members
Posts: 48
Joined: 4-April 08
Member No.: 52552



Hi,
It's been a while since I was last here. Got a quick question.
I've downloaded some video files, that I checked to have an AAC 256KBPS audio part. Let's say I don't want the video part, I want the audio. There are programs which can convert these video files to audio files, but they decode the audio to wav and then convert that to something else. So they transcode the audio. Since 256 k is pretty high quality anyway, I doubt transcoding to something equally high wouldn't make much difference, but still I don't want to lose anything by just taking the video out. Is there a way to cut the video out of the original file?
Thanks.
Go to the top of the page
+Quote Post
DVDdoug
post Jan 3 2012, 19:31
Post #2





Group: Members
Posts: 2441
Joined: 24-August 07
From: Silicon Valley
Member No.: 46454



Try SUPER (FREE!!!). Select "Audio Only AAC" and "Stream Copy" and you should get the audio without re-encoding.

Don't get fooled by the ads for other software on the SUPER website. Follow the links and make sure you are downloading SUPERsetup.exe.
Go to the top of the page
+Quote Post
derty2
post Jan 3 2012, 21:45
Post #3





Group: Members
Posts: 557
Joined: 5-June 11
Member No.: 91257



You can do this easy and fast from the command line using mencoder.exe.

EXAMPLE

I have a video file named input.flv, and I want to extract the raw audio stream to a file named output (at the moment I don't know the file extension).

put mencoder.exe and input.flv in the same folder, and run this command line:
CODE
mencoder -of rawaudio -ovc copy -oac copy -o output input.flv

a file named output is created in the same folder.

Don't close the console window yet ...look at the text. You should see something like this:
QUOTE
C:\TEST=====> mencoder -of rawaudio -ovc copy -oac copy -o output input.flv

MEncoder Sherpya-MT-SVN-r32198-4.2.5 © 2000-2010 MPlayer Team
SSE2 supported but disabled
158 audio & 346 video codecs
success: format: 0 data: 0x0 - 0xebb6d
libavformat file format detected.
[flv @ 02230050] Estimating duration from bitrate, this may be inaccurate
[lavf] stream 0: video (flv), -vid 0
[lavf] stream 1: audio (mp3), -aid 0
VIDEO: [FLV1] 320x256 0bpp 25.000 fps 322.7 kbps (39.4 kbyte/s)
[V] filefmt:44 fourcc:0x31564C46 size:320x256 fps:25.000 ftime:=0.0400
Ignoring video stream!
videocodec: framecopy (320x256 0bpp fourcc=31564c46)
audiocodec: framecopy (format=55 chans=1 rate=22050 bits=16 B/s=1000 sample-0)
Pos: 0.9s 22f ( 3%) 0.00fps Trem: 0min 0mb A-V:0.084 [0:55]

Skipping frame!
Pos: 1.2s 32f ( 6%) 0.00fps Trem: 0min 0mb A-V:0.084 [138:55]

Skipping frame!
Pos: 1.7s 44f ( 6%) 0.00fps Trem: 0min 0mb A-V:0.084 [104:55]

Skipping frame!
Pos: 2.7s 71f (10%) 0.00fps Trem: 0min 0mb A-V:0.080 [152:56]

Skipping frame!
Pos: 24.3s 612f (100%) 0.00fps Trem: 0min 0mb A-V:0.049 [250:57]

Video stream: 250.106 kbit/s (31263 B/s) size: 760322 bytes 24.320 secs 612
frames

Audio stream: 57.752 kbit/s (7219 B/s) size: 177075 bytes 24.529 secs

C:\TEST=====>


So there is our filetype in red; it is an MP3 file ====>output.mp3
Go to the top of the page
+Quote Post
raygrote
post Jan 5 2012, 22:50
Post #4





Group: Members
Posts: 48
Joined: 4-April 08
Member No.: 52552



Thanks for the replies. I will try both.
Go to the top of the page
+Quote Post
killazys
post Mar 10 2012, 15:20
Post #5





Group: Members
Posts: 7
Joined: 25-August 11
Member No.: 93266



Wait. You want to demux the audio, yes? What's the container format? If MKV, use MKVToolNix. If MP4, use MP4Box or with a UI such as YAMB.
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 17th April 2014 - 05:18