Discussion

Hi !
I have a problem when I encode my video using ffmpeg. There is no “index” on the video file. The problem is I can’t resume my video (still start at beginning) and I can’t use ffw /rwd (press center butter, fast circles with your finger). And idea here ?
mOOx
2005/11/21

Hello!
I wrote down my experiences with my new iPod with video. Have a look at http://home.c-otto.de/ipod/
Carsten Otto
C-Otto
2005/11/26

“I have a problem when I encode my video using ffmpeg. There is no “index” on the video file.”

Same problem here. No idea.
Ian Eure
2005/11/27

Ian Eure : Have you tried “two-pass” mode ? Perhaps It will create the “index”. I didn’t try yet.
mOOx
2005/12/01

Just so you know, the qmin and qmax settings will sometimes cause the bitrate to fluctuate by several hundred kilobits per second depending on the video file. I found that the bitrate setting was nearly useless when encoding at 480×480. The test video (an episode of Alias) settled in around 1100K/s because the qmax setting wouldn’t allow the quality to degrade more than 5. You probably need to increase qmax to 9 or 10 in order to keep within a reasonable proximity to 300Kb/s. I also fail to see the usefulness of setting qmin, since if you can get a better quality, why wouldn’t you want it? But perhaps I’m missing something.

I did a quick comparison between using and removing the qmin/qmax settings. I’m using a 43 minute episode of Alias recorded from HDTV as my source video. My command line was (with qmin/qmax):

ffmpeg -vcodec xvid -b 350 -qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ab 96 -ac 2 -i alias.s05e05.avi -s 320×240 -aspect 16:9 alias.s05e05.mp4

Here are the final stats with the settings:

frame=58766 q=3.0 Lsize= 119159kB time=2450.6 bitrate= 398.3kbits/s
video:89073kB audio:28715kB global headers:0kB muxing overhead 1.163105%

The overall bitrate (video bitrate + audio bitrate) is smaller than one might expect, because qmin forced some of the video to be no better than 3, when it could have been better quality.

This is without the qmin/qmax settings:

frame=58766 q=2.0 Lsize= 134562kB time=2450.6 bitrate= 449.8kbits/s
video:104475kB audio:28715kB global headers:0kB muxing overhead 1.029920%

I added an extra 15MB to the filesize when removing the qmin/qmax settings, but the overall video quality is 2 instead of 3. The bitrate is just about on the money (350K/s video + 96K/s audio = 446K/s total). This confirms that qmin was a problem in the first run.

So, what did I deduce from all this? I think qmin shouldn’t be used. It artificially degrades the video when it doesn’t have to. That’s what the target bitrate is for. However, I did see in the second run that qmax may have been useful. There were a few times when the quality went over 10. While I don’t think that’s a particularly important at these low resolutions, it will probably be more useful if you encode at 480×480 for TV. In those instances, setting qmax to 10 would probably be advisable.
Jason Huebel
2005/12/05

Additionally if you are transcoding a video file that is 16:9 (for instance, something captured from HDTV), then the output video file will stretch to fit the height of the iPod screen. This makes the video look quite distorted and causes additional video artifacts during playback. I’m looking into how to resolve this. Maybe you can specify only a width and allow the height to adjust dynamically?
Jason Huebel
2005/12/05

For widescreen videos, use -s 320×192. And if you want to transcode for TV output, you should use these resolutions:

widescreen: 480×288 (1.6666667)
fullscreen: 480×360 (1.3333333)

It appears that the iPod pretty much ignores the -aspect option. So I wouldn’t even bother with it. Here’s my current command line, when converting HDTV/widescreen videos:

ffmpeg -vcodec xvid -i input.avi -b 375 -qmax 10 -bufsize 8192 -g 300 -acodec aac -ab 96 -ac 2 -s 320×192 output.mp4

Note that I added stereo output (-ac 2) and bumped up the buffer size. I also dropped the -qmin option and increased -qmax to 10 so the final file size is more consistent. Even with the higher qmax, my final video quality is still 2 (which is great).

With all this fiddling around with ffmpeg, I’ve decided to start a project to create an tool similar to the Videora iPod Converter (which I believe is closed source). It will probably be Qt based, since I’m an avid KDE user.
Jason Huebel
2005/12/05

I did my own experiments beforehands and for me forward/backward skipping works (and everything else, too). Maybe it’s because I’m using “-f mov”?

Anyway, I wrote down what I did under http://www.julien-oster.de/pov/pmcms/entry/122
maybe it’s of any help.
Julien
2005/12/05

It may be an issue with gtkpod that you aren’t able to seek. Perhaps some meta information is included when the video is copied to the iPod? I’m using ffmpeg on Linux for conversion, but I still use iTunes on my work laptop to copy the videos to my iPod. I can seek fine.
Jason Huebel
2005/12/05

I tried the above command on ubuntu and I am getting “unknown codec ‘xvid’” error. I tried looking for xvid in apt-get but couldnt find one. COuld someone pls help on this error?
ubuntu
2005/12/11

You can use mEncoder to build an index on a file that is missing one, I think.
joel
2005/12/11

I have succesfully used ffmpeg -i input.avi -f mov out.mov for my brand new 5g iPod.
Lasarus
2005/12/13

Converting videos to iPod using GNU/Linux

The fastest way I’ve foud to convert videos to the iPod format using free software is by using the ffmpeg encoder.
It should work in any unix if you have ffmpeg installed. If you use Debian, you can find a good .deb package in nerim.net:

deb …
Imagos
2005/12/22

Can someone please post their FFMPEG configure file? I’ve downloaded the latest FFMPEG CVS and enabled xvid, faad, and flaac, and then get tons of compile errors (under Fedora Core 3).
Joe Briggs
2005/12/23

Ok, lte me address a couple points here.

- Seeking. Definitely a GTKPod issue. I can convert with FFMpeg, put it on the iPod with iTunes, and I can seek fine.

- Unknown XviD codec on Ubuntu: Yup, Ubuntu ships with a pretty crippled FFMpeg. Get the source and recompile it.

- Fullscreen vs. widescreen. I haven’t had any problems. I just change -aspect. I have had no problems with aspect ratios when playing on my iPod or in iTunes.

- qmin setting. It was a concious decision to get more reasonable file sizes. For higher quality I have found that ignoring the q settings and going with ABR works well for me. I’m using: -maxrate 768 -b 512, which will get you an ABR of 512kb, with an upper limit of 768kb. Increasing the upper limit to 1M results in more quality still, and file sizes are still quite reasonable. Two-pass encoding at 768-1000k gives me very acceptable quality.
Ian Eure
2005/12/23

These settings work fine for me (in a batch file, on windows)

ffmpeg -i %1 -f mp4 -r 25 -s 320×240 -b 768 -ar 44000 -ab 112 %1.mp4
Elliot
2005/12/24

Getting movies to ffw and rew with gtkpod:

Drag your movie over to your iPod with gtkpod
Right-click on the movie and click on “Edit details”
Go to the “General” tab and set the play time.
Click Apply and OK.
Sync

The problems comes from gtkpod setting a 0:00 play time for all movies. Manually setting it has worked for every movie I put on so far. I will see about making a patch so gtkpod does this automatically tomorrow.
Mark Duncan
2005/12/24

Ubuntu breezy packages of libgpod (0.3.0) and Gtkpod (0.99.2) with video support available on my website : http://www.badcow.homelinux.net
mOOx
2005/12/28

With gtkpod 0.99.2 and manual setting of play time, I can use ffw and rew correctly but I still cannot use pause / resume. (Watch a video – pause – listen some music – resume video (doesn’t work). Any idea ?
mOOx
2005/12/28

This isn’t working for me, I’m trying to encode tv episodes that are encoded as xvid into ipod supported mp4 files. Here is my parameters:

ffmpeg -vcodec xvid -b 300 -qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ab 96 -i Scrubs.S05E08.PDTV.XviD-LOL.avi -s 320×240 -aspect 4:3 scrubs.mp4

The file plays in quicktime and iTunes fine, but won’t copy to the iPod.

I get this error http://www.flickr.com/photos/maddox/92819725/

Why the heck can’t I get these vids on the iPod?
Jon Maddox
2006/01/29

Great post!

I’m curious though. I really don’t care about file size. I really just want to take a downloaded xvid and convert it so it’ll work on the ipod with little or no degration in quality. (I’m basically using my ipod to watch missed tv shows)

Is there some automated way I can do this… like a batch script which reads the bitrate, framerate, etc from the original and apply those settings to the converted ipod friendly version?
John
2006/02/23

i am using mandriva 10.2 cooker and an athln 64 running in 32 bit mode. i have successfully encoded my xvid files to mp4 using ffmpeg but the video will run fine for a cpl of sec and then freeze, if i do a ff it will be back to normal, its not gtkpod because i use it to xfr some vid dled off the net and it works perfectly, is anybody else getting these problem?

my ffmpeg is built with faac, faad. i had to remove xvid and x264 support to compile.

atm the scriipt is as follows: ffmpeg -i “$1″ -f mp4 -vcodec mpeg4 -b 700 -r 29.970030 -acodec aac -ac 2 -ar 48000 -ab 160 -s 320×240 -aspect 4:3 $2.mp4
Cpt Tripzz
2006/03/12

iPod doesn’t play mp3 audio? Are you sure?
jc
2006/04/22

“iPod doesn’t play mp3 audio? Are you sure?”

It didn’t seem to work for me. I’m specifically referring to MP3 audio tracks in a video file – of course it plays regular MP3 songs just fine.
Ian Eure
2006/04/23

[...] It took me most of yesterday afternoon to work out how to encode video for use on an iPod. ffmpeg will do the trick, as long as you compile it with aac support. The format is mpeg4 video with aac audio, 320×240. For those of you who are interested in the process, here’s a good ffmpeg command line. I encoded and uploaded a video study of mine Study One. Even though this video was designed for high-resolution projection and nearly every frame is different , the compressed version played on a ‘pod conveys quite a bit of the original. I also encoded and downloaded a great abstract film by Harry Smith ‘Court Metrage No. 7 (cocaine)’. This also looked great though the soundtrack was in mono — not necessarily a bad thing as the soundtrack on the version I have is made up of Beatle tunes. [...]
Robert Switzer :: I love my iPod
2006/05/01

I found a way to seek through videos encoded with ffmpeg and imported with gtkpod. The solution is quite easy.
When I was investigating what the problem could be, I thought the problem was in how ffmpeg dealt with the video’s metadata. But the problem was in gtkpod.
When you import a video with gtkpod, click on edit details in the video you just added. In the field “length” write the actual length of the video. The next time you play the video you will be able to seek through it.
When you import videos with iTunes it takes care of extracting the metadata of the video; gtkpod doesn’t. The ipod, therefore, doesn’t know where the video ends: you have to tell it.

I hope this can help people rid off the frustration (such as the one I had).
Carlos
2006/05/18

build mencoder with faac support for -oac faac aka aac encoding support.
compn
2006/07/07

Thought it might help to post my command. It overcomes the no indexing errors by using the moeg4 instead of xvid codec. I can seek fine in the videos, though I may have a newer gtkpod version (0.99.4).

ffmpeg -i input.avi -f mp4 -vcodec mpeg4 -maxrate 2000 -b 1500
-qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ar 44100 -ab 128 -s 320×180 -
aspect 16:9 output.mp4

This is for widescreen. For regular, change the resolution to 320×240, and aspect to 3:4.
Also, you can change the q values and bitrates to your liking.

I am running ffmpeg version 0.4.9 with aac and xvid compiled in on a gentoo system.
Here are my use flags/version:
ffmpeg-0.4.9_p20051216 USE=”a52 aac encode ieee1394 imlib mmx network ogg oss sdl theora threads truetype v4l vorbis xvid zlib -debug -doc -dts -test

Hope this helps someone.
Louis
2006/08/02

Louis’ command line worked like a charm for me! The Tick is playing on my ipod right now, copied there by the cvs build of gtkpod.
Sean
2006/09/11

[...] I found this site. The command (slightly modified, see below): [...]
Junkyard » Blog Archive » ipod in linux….
2007/01/10

what is FFmpeg?
ada
2007/02/15

If you can’t figure out what ffmpeg is on your own, you’ll never get this to work.
Brains
2007/02/19

Hi,

I am not able to use GSM file with ffmpeg on linux. ffmpeg is saying “Unknown Format”. Any idea why i am getting this?
Cirus
2007/03/29

[...] Atomized » Blog Archive » Converting video to play on your iPod with FFmpeg [...]
Dryice Liu’s Blog - converting video to IPod
2007/08/10

[...] How to convert Video to iPod – [...]
geekness » Blog Archive » Bookmarks von 10.09.07 bis 16.10.07
2007/10/18

Atomized

Converting video to play on your iPod with FFmpeg

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