Avidemux Forum

Avidemux => Windows => Topic started by: Kelvin on June 25, 2017, 05:27:54 AM

Title: Video MP4 AVC play failed after merging
Post by: Kelvin on June 25, 2017, 05:27:54 AM
Hi guys
I downloaded two video from youtube, format mp4 AVC. After I merge them with avidemux,  it cannot play when it gets to the latter video.

Avidemux 2.7 nightly build on Windows 10 64bit.
http://www.avidemux.org/nightly/win64/avidemux_r170623_win64Qt5_438.zip

Two video from youtube:

You can download by youtube-dl:

command line:
I attached the project file for more detail.
Title: Re: Video MP4 AVC play failed after merging
Post by: eumagga0x2a on June 25, 2017, 10:27:53 PM
Appending WFM at least with MKV muxer.
Title: Re: Video MP4 AVC play failed after merging
Post by: Kelvin on June 26, 2017, 03:01:29 AM
what does "Appending WFM" mean?
Title: Re: Video MP4 AVC play failed after merging
Post by: eumagga0x2a on June 26, 2017, 08:54:05 AM
Oh, I see now. Only keyframes can be decoded in the appended video after the whole was saved in copy mode.

("WFM" means "works for me", but it really doesn't as I see now).
Title: Re: Video MP4 AVC play failed after merging
Post by: eumagga0x2a on June 26, 2017, 08:54:45 PM
Remarkably, an attempt to join these videos with ffmpeg 3.3.1 results in exactly the same issue (at least when using software decoding). It doesn't matter which video comes first; the second one can't be decoded.

720p versions of the videos doesn't exhibit this problem, btw.
Title: Re: Video MP4 AVC play failed after merging
Post by: eumagga0x2a on June 27, 2017, 03:57:10 PM
Looks like differing stream identifiers (138 vs 266) indicate also different encoding options, which makes videos not mergeable.
Title: Re: Video MP4 AVC play failed after merging
Post by: Kelvin on June 30, 2017, 03:30:05 PM
Yes, the stream 266 has higher quality than 138, that why I choose 266. Hope you find out and fix issue in future version, to make avidemux better and better :D
Title: Re: Video MP4 AVC play failed after merging
Post by: eumagga0x2a on June 30, 2017, 05:02:10 PM
You can't mix 138 and 266. I guess, there is nothing Avidemux could do about it unless you reencode.