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21
Windows / Re: Poor Audio Cuts?
« Last post by eumagga0x2a on October 10, 2018, 09:21:44 AM »
Absolutely no problem with complaining, thank you for raising the question. I actually wanted to encourage to "get hands dirty" and start contributing to shape things to one's liking, at least this is how it worked in my case.

By the way, the only notable change in Avidemux behaviour since the old 2.6.x days when deleting a portion of video was inclusion of the picture matching the B marker (the end point) if it happend to be the last picture of the video. Apart from that, a few changes were made to keep the current position in the video (the currently displayed picture) during editing operations as good as possible to follow the principle of least surprise.

The audio blip is a small portion of the previously decoded audio. I tried to fix it, but it turned out to be quite a difficult task. As explained above, play a silent passage in Avidemux directly before starting a save operation which includes re-encoding of audio. This will result in the blip consisting of silence and thus not noticeable.

If the green flash bothers you, disable DXVA2 display and use the OpenGL (QtGl) output (or feel encouraged to fix the issue yourself!). I get a brief initial corruption when initializing playback using VDPAU as well, but this doesn't bother me. This stuff is not on my todo list.

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Should I just wait for the next nightly and see if that works?

Yes, exactly.
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This is not possible in Avidemux, but you can set the field using ffmpeg with the -metadata option (https://stackoverflow.com/questions/15335073/can-i-set-rotation-field-for-a-video-stream-with-ffmpeg). First edit the video in Avidemux, then set the field with ffmpeg, otherwise it will be discarded.
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Windows / How to change rotation header field for MP4 video without re-encoding?
« Last post by pstein on October 10, 2018, 08:14:09 AM »
As far as I know the  file header of an MP4 video contains some information about the auto-rotation of a video file when played in video player (e.g.VLC).

So I guess users can change this header field (e.g. to 90deg clockwise) without re-encoding the full video.

How does this work in Avidemux?

Peter
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Avidemux-German / Re: Avidemux kann manche TS-files nicht öffnen
« Last post by micaelo on October 09, 2018, 11:44:24 PM »
Avidemux kann nur ein Video pro Stream handhaben, die Mitschnitt-Software oder Hardware schreibt aber zwei Aufnahmen, die zumindest eine kleine Überlappung aufweisen, in eine Datei. Mit dem ersten Sample hatten wir Glück, dass die erste PAT gar keine verwertbaren PMTs enthielt. In den anderen Samples bekommt Avidemux schon aus der ersten PAT einen Videotrack (den der vorherigen Aufnahme) mitgeteilt, der aber eigentlich schon zu Ende ist.

Ich teste gerade ein anderes Schnitt-Programm: VideoReDo TVSuite 5 von https://www.videoredo.com/en/Products_TVSuite_V5.html

Auch mit diesem Programm kann ich die TS-Dateien, die ich mit Avidemux nicht öffnen kann, nicht öffnen. Es gibt dort aber in den Einstellungen die Option "Ignore Transport Stream Maps".

Wenn ich diese Option einschalte, kann ich die fraglichen TS-Dateien öffnen und bearbeiten.

In der Erklärung zu dieser Option heißt es:

"When a transport stream is opened, VideoReDo attempts to determine the available programs in the stream by processing the stream's program maps (PAT and PMT packets). However, many broadcasters either omit these packets or send them with incorrect information. This can cause VideoReDo to not detect all the video and audio streams in the file.
Enabling the option "Ignore Transport Stream Maps" will disable the processing of these sections. Instead VideoReDo scans the first 10,000 packets of the file and tries to decipher what program contents are present. The disadvantage of disabling this feature is that the program does not always pick up each and every stream, especially secondary audio streams. The preferred mode is to leave the option "Ignore Transport Stream Maps" enabled unless your particular transport stream opens with missing audio or video streams."


Vielleicht lässt sich eine solche Option auch in Avidemux einbauen?

25
Main version 2.6 / Re: Timestamp issues
« Last post by CryGuy on October 09, 2018, 09:57:30 PM »
A/V sync is not wrong. I've once subscribed the RSS feed for Avidemux at Github and saw the change lately, but didn't closer to the date. So I'm gonna wait for the next build.

I understand that shifting is necessary to avoid negative values due to the unsinged data type, but in the sample files, there is no negative PTS (and no negative DTS), hence nothing needs to be shifted IMO. And I can't follow the way it's done.. but anyway I'll wait for the next build.
Thanks.
26
Windows / Re: Poor Audio Cuts?
« Last post by BatmanLoko9 on October 09, 2018, 09:10:41 PM »
I hope, the tentative fix doesn't break stuff. As to my brief testing, it solves the issue with last bits of audio in the saved video missing when the video stream contains B-frames for libavformat based muxers (Mp4, Matroska, not mp4v2).

Once a new nightly gets generated and uploaded, please test and report back.

Ah, sorry, I didn't see this post before making my previous one. Should I just wait for the next nightly and see if that works?

I do however want to bring attention to some of the other issues I mentioned with 2.7 in my previous post though, such as the initial audio blip that occurs in some cuts and is present in the video I posted above. The flashing green screen for playback is also problematic, as 2.6 seemed to handle this better, but it is not a major issue.
Have you been able to replicate them, or know of a fix?

Apologies if it sounds like I'm complaining too much, Avidemux has actually served me very well and like I said, I really do like it
27
Windows / Re: Poor Audio Cuts?
« Last post by BatmanLoko9 on October 09, 2018, 09:04:05 PM »
Of course, you must ensure that A/V sync is correct. You could try if disabling B-frames makes the problem disappear.

Sorry, I'm not really sure how to do this, or how to modify the code. 

The possibly relevant location in code would be the part of the muxerFFmpeg::saveLoop function following avidemux_core/ADM_coreMuxer/src/ADM_coreMuxerFfmpeg.cpp:556.

This is pure cosmetics, isn't it? Might be related to the DXVA2 video accel.

Yeah, it just effects playback, not the output but it seems worse in 2.7 than it was in 2.6

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Well, I see it other way round, so WONTFIX. You could become an important Avidemux contributor, then modify the behaviour to your liking.

I completely understand that, I didn't mean to be disrespectful, I was just stating my preferences. Unfortunately I don't know enough to learn how to do that, this is just a program I've enjoyed using for a long time but have had these issues I never understood. I will move on to updated versions eventually, but at the moment for me, 2.7 doesn't offer more than 2.6.

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I strongly doubt that this issue (I tried to locate and to solve it, yet without success) is specific to 2.7.x. It is a small amount of previously decoded audio in a buffer, so if the last thing you played in Avidemux was silent, you would avoid this audio blip.

All fixes go only into 2.7.x and later, obviously. So staying at 2.6.21 is not a solution.

The issue does seem specific to 2.7. I have uploaded 3 more clips to demonstrate the problem.

Here is the clip from Avidemux 2.6:
https://youtu.be/1EggraTCgIw

Here is the same clip but in Avidemux 2.7:
https://youtu.be/2sHpk28Q7oY

And here is the same clip but cut in Premiere Pro:
https://youtu.be/_YgF61Dkk1Y

As you can hear, in 2.7 there is a little audio hitch in the beginning, which isn't present in the other 2 cuts despite starting and ending on the exact same frames. It doesn't happen all the time, sometimes 2.7 behaves fine, but other times I have issues like this.
Also, as before, Premiere Pro gets the full, complete audio, whereas Avidemux seems to cut off early. Is there anything I can really do to fix this, and get precise cuts? I uploaded the audio tracks above if they're of any help.

I really do like Avidemux, it's a brilliant program but I just can't wrap my head round this issue and would like to solve it somehow.

Thanks for all the help

28
Main version 2.6 / Re: avidemux works fine but trying the same with ffmpeg don't
« Last post by eumagga0x2a on October 09, 2018, 07:00:44 PM »
The search for the actual bug in Avidemux is ongoing, but the nature of the problem becomes apparent: when indexing TS files, Avidemux gets the size of each keyframe slightly wrong (in the samples I tried +6 bytes), which means that following PES packets are shifted 6 bytes relative to respective frame boundaries. This confuses ffmpeg which sees the beginning of a second frame in the first packet but doesn't have DTS/PTS for it yet. When the second packet arrives from the demuxer, it pushes it with timestamps unset to the muxer so that saving fails.

If you edit the .idx2 file to subtract 6 from the first field following each IF or DF marker, reload the TS file in Avidemux and save a portion of it in copy mode using the MpegTS muxer, ffmpeg is able to remux resulting video to mkv without problems.
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Main version 2.6 / Re: Timestamp issues
« Last post by eumagga0x2a on October 09, 2018, 06:39:37 PM »
If the video is stored in a mp4 container and the A/V sync is clearly wrong, than you see probably the issue fixed by [demuxers/Mp4] Fix track delay calculation, media time is in track timescale units, not in movie timescale, no official nightlies have been built since then yet.

The timing displayed by Avidemux differs from the one shown by FFmpeg because Avidemux uses uint64_t for timestamps while ffmpeg uses int64_t (rounding errors from ticks to microseconds conversion nonwithstanding). This requires all timestamps to be shifted to avoid some timestamps going negative.
30
Windows / Re: Poor Audio Cuts?
« Last post by eumagga0x2a on October 09, 2018, 06:27:35 PM »
I hope, the tentative fix doesn't break stuff. As to my brief testing, it solves the issue with last bits of audio in the saved video missing when the video stream contains B-frames for libavformat based muxers (Mp4, Matroska, not mp4v2).

Once a new nightly gets generated and uploaded, please test and report back.
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