[SOLVED] OGV Trouble

2mac · 2014-01-23 23:43:09

By request of an online community which I host, I have begun to make some Java tutorials geared toward Bukkit plugin development. That aside, I am able to make high-quality (audio and video, anyway) recordings using RecordMyDesktop. However, the application only stores the recording in ogv format. By itself, this is fine. However, I want to cut off the beginning pause and any footage at the end of myself stopping the recording.

I would PREFER one of these solutions:

1. A video editor that supports OGV input.

2. I am currently using FFmpeg to convert my video into MKV format which can be used by OpenShot. However, when OpenShot reads the video, there is noticable lag, and the already choppy audio increases significantly in pitch. The footage simply becomes worthless at that point. I have attempted to use HandBrake, which produces MKVs that don't have these problems with OpenShot, but the audio and video struggle to line up, which is irritating. Is there a better way to convert to MKV? Or is my process just fine while RecordMyDesktop has problems putting out a clean OGV when recording?

To clarify, I'm using the following to convert to MKV using FFmpeg:

ffmpeg -i out.ogv -vcodec libx264 -preset veryslow -qp 0 -acodec libmp3lame java02.mkv

I have also tried setting the "acodec" option to "copy" but I got the same result. Also, VLC has no problems playing both the OGV and the MKV with perfect quality. There doesn't seem to be anything wrong with the MKV, but rather with the way that OpenShot looks at it.

Last edited by 2mac (2014-02-01 00:58:38)

skottish · 2014-01-24 00:13:37

I've had strange results with FFmpeg and mkv files over the years. One thing that you can try is to run the output through mkvmerge from mkvtoolnix. It has a tendency to fix timestamp issues and such.

2mac · 2014-01-24 02:31:10

I'm having trouble following you. Are you suggesting that I use mkvmerge THROUGH FFmpeg, or am I totally off-base?

2mac · 2014-01-24 02:37:25

Okay, I realize I WAS totally off-base. I ran the GUI version of mkvmerge, which worked fine, but OpenShot still reacts like it has been.

Andreaskem · 2014-01-24 11:55:36

If you only want to cut off parts at the beginning and end, can't you just use something like this:
http://askubuntu.com/questions/59383/ex … ne-command
?

DrZaius · 2014-01-25 01:18:04

stream copy

You can use ffmpeg to stream copy (re-mux) the video choosing only the section you want. There is no re-encoding so the whole process will be fast, your output formats will remain the same, and you will experience to quality loss.

In this example the first 12 seconds is skipped and the output duration will be 1 hour long.

ffmpeg -ss 12 -i input.ogv  -t 01:00:00 -codec copy output.ogg

Or use "-to" instead of "-t". From the documentation:

‘-t duration (output)’
Stop writing the output after its duration reaches duration. duration may be a number in seconds, or in hh:mm:ss[.xxx] form.
-to and -t are mutually exclusive and -t has priority.
‘-to position (output)’
Stop writing the output at position. position may be a number in seconds, or in hh:mm:ss[.xxx] form.
-to and -t are mutually exclusive and -t has priority.

lossless intermediate format

If you feel like you must use an editor then a lossless* intermediate format will probably be best. It will probably be more editor friendly, but it can also be a huge file (but it's intended to be temporary). huffyuv and pcm_s16le in mkv will probably be fine:

ffmpeg -i input -codec:v huffyuv -codec:a pcm_s16le output.mkv

* Excluding any potential loss from chroma subsampling but that will probably occur during capturing with recordmydesktop and not when re-encoding in this case.

Arch Linux

#1 2014-01-23 23:43:09