linux ffmpeg gurus - inside please - GoFuckYourself.com

borked · 02-11-2007, 02:14 PM

OK, I've officially spent 24 hours pulling my hair out trying to understand why whenever I transcode an mpg video to mpeg-4 with ffmpeg I have no sound.

input file: ffmpeg -i input.mpg gives

Code:

ffmpeg version 0.4.9-pre1, build 4718, Copyright (c) 2000-2004 Fabrice Bellard
  built on Feb 11 2007 12:55:31, gcc: 3.4.2 [FreeBSD] 20040728
Input #0, mpeg, from 'input.mpg':
  Duration: 00:00:15.6, bitrate: 1523 kb/s
  Stream #0.0: Video: mpeg1video, 352x288, 25.00 fps
  Stream #0.1: Audio: mp2, 44100 Hz, stereo, 224 kb/s
Must supply at least one output file

transcode with:
ffmpeg -i input.mpg -acodec aac -ab 224 -ar 44100 output.mov

gives

Code:

fmpeg version 0.4.9-pre1, build 4718, Copyright (c) 2000-2004 Fabrice Bellard
  built on Feb 11 2007 12:55:31, gcc: 3.4.2 [FreeBSD] 20040728
Input #0, mpeg, from 'input.mpg':
  Duration: 00:00:15.6, bitrate: 1523 kb/s
  Stream #0.0: Video: mpeg1video, 352x288, 25.00 fps
  Stream #0.1: Audio: mp2, 44100 Hz, stereo, 224 kb/s
Output #0, mov, to 'output.mov':
  Stream #0.0: Video: mpeg4, 352x288, 25.00 fps, q=2-31, 200 kb/s
  Stream #0.1: Audio: aac, 44100 Hz, stereo, 224 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
[mpeg4 @ 0x282dd310]removing common factors from framerate
Press [q] to stop encoding
frame=  439 q=12.9 Lsize=    1118kB time=16.7 bitrate= 547.0kbits/s    
video:548kB audio:450kB global headers:0kB muxing overhead 11.954272%

looking out the output file with ffmpeg -i output.movgives:

Code:

ffmpeg version 0.4.9-pre1, build 4718, Copyright (c) 2000-2004 Fabrice Bellard
  built on Feb 11 2007 12:55:31, gcc: 3.4.2 [FreeBSD] 20040728
Input #0, mov,mp4,m4a,3gp, from 'output.mov':
  Duration: 00:00:17.5, bitrate: 521 kb/s
  Stream #0.0: Video: mpeg4, 352x288, 25.00 fps
  Stream #0.1: Audio: mpeg4aac, 44100 Hz, stereo

The resulting .mov has no sound EXCEPT in VLC, that plays it.

Now if I split the audio from the input using -vn:
ffmpeg -i input.mpg -vn -acodec aac -ab 224 -ar 44100 output.mp4

the audio track is fine, showing the mpeg4aac codec for ffmpeg is fine.

WTF gives???
plus, no matter what I set the bitrate to, it never encodes at that rate - it just does it's own thing.

Any help would be appreciated!!

borked · 02-11-2007, 02:19 PM

Oh for the frikkin love of god.

Can you believe it - just writing it out in a post, I saw what was going on...
the .mov codec is obviously borked, since a simple encode:

ffmpeg -i input.mpg output.mp4

gives video and sound

Aaaaaaaaaarggggggggg!!
I went through everything today to understand that, even spending 3 hours trying to install mpeg4ip....

thx for looking!

Damian_Maxcash · 02-11-2007, 02:24 PM

I havnt played with FFMpeg for ages - have they got it working with the new Flash video format yet?

Aric · 02-11-2007, 02:25 PM

That happens alot to me...

Once I type out the problem to someone else, I immediately see where the problem is after I hit "Send"

borked · 02-11-2007, 02:36 PM

Quote:

Originally Posted by damian2001

I havnt played with FFMpeg for ages - have they got it working with the new Flash video format yet?

I have the same problem encoding to flv - no sound even though mp3 codec is kicking in (from mp3lame installation)

not sure if it's the 'new' flv format... all new to me

Damian_Maxcash · 02-11-2007, 02:43 PM

Quote:

Originally Posted by borked

I have the same problem encoding to flv - no sound even though mp3 codec is kicking in (from mp3lame installation)

not sure if it's the 'new' flv format... all new to me

It should work OK with V7 video (Sorenson?), but last time I looked it would only decode and not encode V8.

Damian_Maxcash · 02-11-2007, 03:02 PM

Quote:

Originally Posted by damian2001

It should work OK with V7 video (Sorenson?), but last time I looked it would only decode and not encode V8.

I just has a quick read about this - its seems that Sorenson that is used in FLV version 7 was made just for Adobe, and was made available pretty openly.

The FLV V8 codec was made by On2 (On2 VP6) - and is only on licence to Adobe - so they are making a killing selling the licence to sites like YouTube, Google etc.

So I doubt FFMpeg will ever fully support it.

borked · 02-11-2007, 03:32 PM

Quote:

Originally Posted by damian2001

I just has a quick read about this - its seems that Sorenson that is used in FLV version 7 was made just for Adobe, and was made available pretty openly.

The FLV V8 codec was made by On2 (On2 VP6) - and is only on licence to Adobe - so they are making a killing selling the licence to sites like YouTube, Google etc.

So I doubt FFMpeg will ever fully support it.

Yup, I just tested it - mpg to flv works fine on 7 but on 8 gives zero.

(My sound problem was mp4 to flv.)

Still, from what I've seen encoded so far, there isn't a huge difference in filesize between mp4 and flv encodings, although mp4 is a bit crap for streaming w/r to user base compatability.

I'm just getting into this encoding game, so I'm a bit behind, but mp4 embedding in pdf looks to be a winner - shame damn Adobe are guarding flv embedding to pdf close to their chest. Looks like flv is going very much commercial, but not for the end user.

02-11-2007, 02:19 PM	#2
borked Totally Borked Industry Role: Join Date: Feb 2005 Posts: 6,284	Oh for the frikkin love of god. Can you believe it - just writing it out in a post, I saw what was going on... the .mov codec is obviously borked, since a simple encode: ffmpeg -i input.mpg output.mp4 gives video and sound Aaaaaaaaaarggggggggg!! I went through everything today to understand that, even spending 3 hours trying to install mpeg4ip.... thx for looking! __________________ For coding work - hit me up on andy // borkedcoder // com (consider figuring out the email as test #1) All models are wrong, but some are useful. George E.P. Box. p202

02-11-2007, 02:25 PM	#4
Aric Confirmed User Industry Role: Join Date: Sep 2002 Posts: 1,209	That happens alot to me... Once I type out the problem to someone else, I immediately see where the problem is after I hit "Send" __________________ Awesome cloud hosting by DigitalOcean

02-11-2007, 02:24 PM	#3
Damian_Maxcash So Fucking Banned Join Date: Oct 2002 Location: MaxCash.com Posts: 12,745	I havnt played with FFMpeg for ages - have they got it working with the new Flash video format yet?