Join two mp4 videos with Avidemux (and similar tools)

[benzio]

Hello everyone. It's two days I'm struggling with two videos I want to join without losing quality.

The two videos are of different resolution BUT... I can sacrifice the quality of the first, in order to keep the stream of the second video intact (no quality loss caused by reconversion)

So, first of all I have converted the first video to match the same resolution of the second. Then I tried to join the two videos, using a direct stream copy but the result does not work: when I play the result with VLC (or other softwares) the video stops at the point where the files were merged.

I attach a short example of what the problem is. In the Zip the video named "Video1.mp4" is the first video (which can be recompressed), the file "Video2.mp4" is the second video that I don't want let it lose quality. The result of joining video1 and video2 (of the same resolution) is "result.mp4".
Any help is appreciated.

[Baldrick]

Try join with something else like mymp4boxgui or mp4joiner or mkvtoolnix(it will make a mkv) .

Did you also match/check the video and audio codecs? And frame rate?

[benzio]

I've tried with any concievable software (mymp4boxgui and mp4joiner too) but nothing worked.

At the end I've solved in this way:
the second video was downloaded from youtube, the first was not.
I've uploaded the first video on youtube and redownloaded it.
For some reason now they are compatible.

[jagabo]

I extracted the raw h264 and aac files with MP4Muxer. Then appended/muxed them with MkvToolnix. The resulting MKV file plays properly.

But if I remux the MKV contents back to MP4 with MP4Muxer the first half doesn't play properly. If I remux with YAMB the second half doesn't play properly.

Some differences I see: the first part has 3 consecutive bframes, the second only 2. And part 1 has profile@level Main@L3.2, part 2 Main@L3.0.

[XenonS]

Hi benzio,
I'm really not an expert in videos, but I happen to read your post. Please read my very recent post "Timestamp error messages when joining MP4s with ffmpeg" just here below and use the latest ffmpeg.exe to join MP4 videos WITHOUT re-encoding which should assure no quality loss if the parameters of your videos are identical. I don't know if this fits what you want, but it's worth a try I think. If you use the batch of my post, just be sure to put your various videos in the same dir as ffmpeg.exe and adjust the batch as for the nr. of videos.

Greets,
XenonS

[benzio]

Thank you everyone for the replies. I will search something about the "bframes" and I'll take a look to XenonS's post.

[bulgom]

.
Hi —— BTW: nice, the doggy! ——


I tried it also, as I encounter such problems "once in a while" (that is: too often), as we all do,

to end up with an .mkv + an .mp4 file of ~6 seconds.

So, as you asked: 1st video: recoded (had to be done anyway); 2nd video: NOT recoded.


1. Sample 1: recoded by "x264" within "Avidemux" v. 2.5.6 (since v. 2.6.x recoded "too short"...) @ 1504 kbs 2-pass "veryslow" (to maintain image quality). With NO audio (audio track disabled). And to AVI container, not MP4, yet.


2. Sample 2: simply remuxed to AVI container. So: no recoding. Using "Avidemux" 2.5.6. With NO audio (audio track disabled).

Note · with audio tracks enabled, "Mkv Toolnix" would refuse to append... And to MP4 container: problems again...

3. "Sample 1" + "Sample 2" joined using "MkvToolnix". With warning, but OK.


4. The two audio tracks joined (with "Cool Edit Pro" ) + saved to WAV; and converted back to AAC using "Pazera" ("Cool Edit Pro": very handy but not reliable enough on AAC compression).

5. Last muxes: .mkv video + .aac audio, using "Mkv Toolnix";

and finally, .mkv video remuxed back to .mp4, using "AviDemux".

Although I didn't recode the 2nd sample, in such a case, I simply think both videos should be recoded, of course — and, if possible, at once:

i.e.: if they accept to be opened / appended onto "AviDemux" interface — and they did (no saving without recoding, OK, but append on "AviDemux" window accepted).

Otherwise, compatibility with many players will remain very unsure!

That's what "YouTube" did anyway. They recode everything. Therefore, no wonder why both videos can now be easily appended. But that's not what you wanted...

Of course, you could have done it yourself, using "AviDemux" (or else).


"Media Info" reports 2555 kbs as video bitrate on "vid. 1" and 934 kbs on "vid. 2"... Quality wise, no problem, as long as you recode the whole movie (vid. 1 + vid. 2) using two-pass compression, and slowly enough ("slow" or "veryslow" setting); and at, say, 1504 kbs.

At THAT image size (854 × 480 pixels), the result should be good. Use the "x264" codec, either within "AviDemux", or even "VirtualDub" ("x264" version VfW in that case).

Of course, on long movies, it's more time consuming than "YouTube" recoding — unless you have a quite powerful PC.

.

[XenonS]

benzio,
try out this for joining your videos with MP4Box:

MP4Box -cat video1.mp4 -cat video2.mp4 -new output.mp4

...Or use the mymp4boxgui and chose Join. Maybe replace the files inside the 'Tools' folder of mymp4boxgui with the latest version of MP4Box.

XenonS

[anime12345]

YAMB is All you Need

[jagabo]

YAMB did not work.