Problems cutting AVCHD

[Heldenkaiser]

Good morning,

I am new to Avidemux. I am trying to use it to cut my AVCHD video clips, but there seem to be some problems.

1) The clips play alright, but the software doesn't recognize the format. In the information tab it says "aspect ration unknown" and displays the video as 4:3 instead of 16:9.

2) Also, the frame rate is identified as 50 fps. Shouldn't it be 25?

3) When I save the output as copy/copy/AVI Muxer--which shouldn't really do anything except save them, right?--, the clips become corrupted in some way. They play fine before cutting, but when I play the newly saved files, the audio stutters and the video stops playing after a few seconds.

4) However, when I use a different software to convert these files to DVD format, they play alright again.

Something is clearly wrong, but is this a bug or is there anything I am doing wrong? I am quite new to this software, however, I have been cutting and editing videos for years with other software and have never run into this kind of problem.

I have experimented with other output formats and with converting the framerate to 25 manually. Some of these combinations work, but it seems the video quality suffers.

As an aside, selecting "DVD" or in fact any other entry in the "Auto" menu doesn't do anything.

Thank you for any help. :-)

[AQUAR]

It may be more usefull to post the output of mediainfo.

Mediainfo provides detailed information about video files.
Get it at http://sourceforge.net/projects/mediainfo/files/binary/mediainfo-gui/

With reliable baseline data you are more likely to get a meaningfull response.

[mean]

samll sample would help
Manufacturers are very creative with the .mp4 file format

[Heldenkaiser]

It may be more usefull to post the output of mediainfo.

Yes, thank you. This is a sample mediainfo output for a video file I have problems opening properly in Avidemux:

General
ID                                       : 0 (0x0)
Complete name                            : E:\Videos\Temp\00000.MTS
Format                                   : BDAV
Format/Info                              : Blu-ray Video
File size                                : 267 MiB
Duration                                 : 5mn 16s
Overall bit rate mode                    : Variable
Overall bit rate                         : 7 077 Kbps
Maximum Overall bit rate                 : 13.7 Mbps

Video
ID                                       : 4113 (0x1011)
Menu ID                                  : 1 (0x1)
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.0
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 2 frames
Format settings, GOP                     : M=3, N=12
Codec ID                                 : 27
Duration                                 : 5mn 16s
Bit rate mode                            : Variable
Bit rate                                 : 6 532 Kbps
Maximum bit rate                         : 12.0 Mbps
Width                                    : 1 440 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.168
Stream size                              : 246 MiB (92%)

Audio
ID                                       : 4352 (0x1100)
Menu ID                                  : 1 (0x1)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : 129
Duration                                 : 5mn 16s
Bit rate mode                            : Constant
Bit rate                                 : 256 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Delay relative to video                  : -80ms
Stream size                              : 9.65 MiB (4%)

Now this is the same file after opening it in Avidemux (with the problems described, aspect ratio not recognized, double frame rate etc.) and saving it with "copy/copy/Avi Muxer". This is the file that has audio stutter and the video hangs after a few seconds:

General
Complete name                            : E:\Videos\Versuch\00000.avi
Format                                   : AVI
Format/Info                              : Audio Video Interleave
File size                                : 253 MiB
Duration                                 : 5mn 16s
Overall bit rate mode                    : Variable
Overall bit rate                         : 6 718 Kbps

Video
ID                                       : 0
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.0
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 2 frames
Format settings, GOP                     : M=3, N=12
Codec ID                                 : H264
Duration                                 : 5mn 16s
Bit rate mode                            : Variable
Bit rate                                 : 6 439 Kbps
Maximum bit rate                         : 12.0 Mbps
Width                                    : 1 440 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 50.000 fps
Original frame rate                      : 25.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.083
Stream size                              : 243 MiB (96%)

Audio
ID                                       : 1
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : 2000
Duration                                 : 5mn 16s
Bit rate mode                            : Constant
Bit rate                                 : 256 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 9.65 MiB (4%)
Alignment                                : Aligned on interleaves
Interleave, duration                     : 32 ms (1.60 video frames)

Any idea what I'm doing wrong?

[Heldenkaiser]

samll sample would help

Can you elaborate? Sorry, I am quite new to this all. Thank you!

[mean]

A small sample video
10 sec is enough

[Heldenkaiser]

A small sample video
10 sec is enough

Yes, thank you. Do you mean a sample of the original video or of the output after saving in Avidemux?

[mean]

The original one

[Heldenkaiser]

Here is a 10-second sample: http://acwgc-usa.org/Video/00001.MTS

[AQUAR]

Mean is of course the best qualified to help with the issues you are experiencing with this video clip.

I'll just point out that this clip is interesting in that it seems to be interlaced and anamorphic.
A bit of help, on the side line from another enduser, is that:

Avidemux displays the stored pixels of all video as if it has a pixel aspect ratio of 1:1.
Considering this video has pixels dimensions of 1440:1080  =  4:3  then the display aspect will be 4:3.

When you just cut and copy this video, its original pixel aspect ratio is lost (set to 1:1 for pc displays!).
Hence the copy you made with avidemux will look "squashed" on a media player.

You need to set the correct meta data value for the pixel aspect ratio if you wish to keep the original display aspect.
Avidemux can do that, but only when recoding (which you might want to do for eg de-interlacing and resampling to match a PC display).

The avi container is not so suited for storing this complex video stream, so I would use the MP4 or MKV muxer in avidemux.
If you use MKV, then you can use MKV merge to remux the streams (video, audio).
This will let you change/correct this meta data for pixel aspect ratio, so that it will again be interpolated to a 16:9 display aspect.

The 50 fps issue is probably a mis-interpretation between fields per second (interlaced video) and frames per second (2 fields make one fame).
 

[mean]

confirmed, something wrong is happening with that video

[mean]

It was linked to my previous vdpau fix

Could you detail what you are doing ?
I've cut a chunk of the video and saved them as mp4/mp4v2/DVD and the output files look alright

[Heldenkaiser]

Avidemux displays the stored pixels of all video as if it has a pixel aspect ratio of 1:1.
Considering this video has pixels dimensions of 1440:1080  =  4:3  then the display aspect will be 4:3.

When you just cut and copy this video, its original pixel aspect ratio is lost (set to 1:1 for pc displays!).
Hence the copy you made with avidemux will look "squashed" on a media player.

Thank you for your reply! But I am not sure I understand this. I agree that 1440:1080 = 4:3, obviously. But my original video isn't 4:3 but 16:9. The mediainfo output file I posted above says so right in the next line, and that's also what I'm seeing.

Or are you saying that what I am seeing is 16:9, but really it isn't?

The funny thing is that when I open the original file in anything BUT Avidemux, the 16:9 ratio is preserved. And the 4:3 in Avidemux looks plain wrong (for instance, people's faces are deformed, etc.).

The avi container is not so suited for storing this complex video stream, so I would use the MP4 or MKV muxer in avidemux.
If you use MKV, then you can use MKV merge to remux the streams (video, audio).
This will let you change/correct this meta data for pixel aspect ratio, so that it will again be interpolated to a 16:9 display aspect.

I tried saving the file as MKV, but I still get the wrong aspect ratio, plus it's still 50 fps instead of 25. Also, the file doesn't play in any software I know.
Would you mind telling me EXACTLY which settings I should use? I feel sort of overwhelmed by the many possible combinations.

The 50 fps issue is probably a mis-interpretation between fields per second (interlaced video) and frames per second (2 fields make one fame).

Are you saying that's simply something the software recognizes wrongly, but it's still right?

Sorry for being so ignorant.

[Heldenkaiser]

Could you detail what you are doing ?
I've cut a chunk of the video and saved them as mp4/mp4v2/DVD and the output files look alright

So far I have done nothing more than open the video in Avidemux (v. 2.6.8, 64 bit) and after cutting save it as "Video Output: Copy", "Audio Output: Copy", "Output Format: Avi Muxer", in the hope of getting a cut version of the same video, for use in a DVD authoring program.

I tried also what you said here and saved the file as "Output Format: MP4" instead. This gives an error message "only AAC & mpegaudio supported for audio". "Output Format: MP4v2" works, but I have no sound. And I don't have a "DVD" entry in that menu, or really anywhere save in "Auto", and whatever I do there doesn't do anything.

[Heldenkaiser]

OK, after playing with the settings some more, I seem to get a reasonable working output with

Video Output: Copy
Audio Output: MP3 (lame)
Output Format: MP4 Muxer

It plays alright, it has sound, it has the correct aspect ratio, although it still says "50 fps" and "4:3" in the Mediainfo output. I am not quite sure about the quality, but since making a DVD from it spoils the quality anyway (or doesn't it?) maybe I'll just live with this solution, even though I don't understand it. Unless of course somebody can suggest better settings?