Avidemux > Stable branch (2.5) discussion

Various questions

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fturco:
Hello. I'm a new Avidemux 2.5.4 user. I use it to cut commercials out of TV recordings and compressing the resulting video.

Question #1
Is it possible, in copy mode, to precisely cut unwanted parts of the video even if the B marker is not a keyframe (I-frame)? I don't want to have broken frames or to re-encode some frames as in smart copy.

Question #2
Is there a simpler way to encode videos in H264 format (MPEG4 AVC)? For now, I just set the options for the final file size and the original aspect ratio, ignoring everything else because I find other options to be excessively complicated or undocumented. Anyway I'd like to have an high quality video, even at the expense of encoding time.

Question #3
I have problems at saving to MPEG2-TS format because, as the process goes, the video size increases but the audio size doesn't, and the final file has audio problems.

Thank you.

hinterwaeldler:
welcome to avidemux :)

A1:
tv recordings should be stored as mpeg-ts. cutting is only possible on keyframes.
take a look at http://en.wikipedia.org/wiki/I-frame
as seen there, not all pictures are stored completly -> rencoding is necessary

A2:
if you expect hight quality you should use filtering. some basic are placed directly inside of avidemux.
even more powerful (and complex) using avisynth http://avisynth.org/mediawiki/Main_Page which could be used as an input to avidemux via avsproxy.

"simply high quality" could be managed via the quantization factor. documentation can be found directly inside of the x264 documentation (iirc x264 is used instead of h264, which is a free implementation of h264)
the remaining options are documented inside of x264 too.

aspectet ratio should not be modified as long as using avidemux directly

A3:
are you using two-pass enconding? if so during the first pass no audio processing should be done at all. should be taken into account only in the second pass

what kind of audio codec is used?
is there no sound at all?

hope i could help you

fturco:
Question #2
I already looked at http://www.avidemux.org/admWiki/doku.php?id=tutorial:h.264, but some options, such as "keyframe boost" or "temp blur of quant after cc", are not documented there.

Question #3
I was just cutting commercials out of a MPEG2-TS file, and writing the resulting video as another MPEG2-TS file, in copy mode. There was sound at the beginning of the output file, but in the middle of playback sound disappeared.

Jan Gruuthuse:
#A3
avidemux 2.5.4 has come to certain age.
For MPEG-TS: use 2.5.6 or 2.6 beta (h.264 or avc). With 2.6 cut on Keyframes (select only with keyboard up/down cursor).
Load complete movie, don't let program auto append. Append each following part manual (.001, .002, .003, ...) with keyboard shortcut press simultaneous:
2.5.6: [Ctrl] [Alt] [A]
2.6 [: Ctrl] [A]
move to start of block you want to cut out: press [ marker A set (Keyframe)
move to end of block you want to cut out:  press ] marker B set
press [Ctrl][x] (Keyframe) <- changed
move to next block to cut out and repeat as above
when finished cutting move to start where you want to save video clip
press [ marker A set (Keyframe)
goto end of video clip, press ] marker B set
now save marked video

hinterwaeldler:

--- Quote from: Jan Gruuthuse on June 28, 2012, 03:41:16 PM ---move to start of block you want to cut out: press [ marker A set (Keyframe)
move to end of block you want to cut out:  press ] marker B set

--- End quote ---

think this is wrong the frame after B has to be a keyframe as it's the reference for the remaining parts.
if the removed part starts with a keyframe or not is not relevant at all
pressing [Del] removes frames too (as C-x is cut (i know many people use it to delete parts))

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