How to merge any short video sequences downloaded from youtube ?

[guista]

Hi all,

I downloaded a set of short sequences from different Youtube sources.
Now, I would like to merge them all together in order to put them all in one single video file.
I successfully converted all the flv streams to mkv.
But when I try to merge them all, mkvmerge complains about the different file formats.

Even if all my files are mkv, the video tracks were encoded with differents codecs as for the audio tracks. Moreover, the video resolution differs from one video to another. This is the same problem for the audio codecs.

So my question are :

* What are the pre-requisities for merging 2 video mkv files ?

* Should they have to be encoded with the same audio/video codec and at the same rate ?

* Must they have the same resolution ?

Thanks in advance for helping me.

[jkauff]

Try converting each FLV file to MP4 and then try your merge. That way they'll all have the same codec.

You could also use a video editor like Nero Video that can do conversions, too (via Nero Recode). The Nero suite has a trial version.

[therube]

MP4 is a "container". And while you can convert an FLV (also a container) to an MP4, assuming you have not re-encoded its contents, simply converting from FLV to MP4, in this case, with dissimilar content, will not help.

FFmpeg: 3.13 How can I join video files? (http://ffmpeg.org/faq.html#How-can-I-read-DirectShow-files_003f)

FFmpeg: How to concatenate (join, merge) media files (https://trac.ffmpeg.org/wiki/How%20to%20concatenate%20(join,%20merge)%20media%20files)

[jkauff]

You're quite right, I was assuming a a re-code to H.264 in the conversion to MP4. Should have made that clearer.

[Lighto]

So my question are :

* What are the pre-requisities for merging 2 video mkv files ?

* Should they have to be encoded with the same audio/video codec and at the same rate ?

* Must they have the same resolution ?

Thanks in advance for helping me.


Looks like you answered most of the questions yourself....
Try re-encoding all your source into the same resolution, codec and container before using MKVMerge to append/join.

[Darksoul71]

From my experiences with Youtube videos (and other sources like smartphones) merging multiple seperately encoded movies (even if they have identical parameters) result in either async audio and/or stuttering video at the merge points. For me it has worked best to simply first re-encode each snippet (at identical resolution / audio sample frequencies / frame rate /etc) to a lossless format (e.g. HuffYUV, Lagarith, PCM Audio), then merge the lossless snippets and encode them to the final format.

This way I never experience async audio or any visible corruption at merge points but depending on the amount of video snippets you want to merge, it is a lot of manual work. For the quick and dirty method I often drop the videos into Freemake Video Converter, hit the merge button and transcode to the format of my choice (e.g. AppleTV, MKV).

HTH,
D$

[nakTT]

Hi all,

I downloaded a set of short sequences from different Youtube sources.
Now, I would like to merge them all together in order to put them all in one single video file.
I successfully converted all the flv streams to mkv.
But when I try to merge them all, mkvmerge complains about the different file formats.

Even if all my files are mkv, the video tracks were encoded with differents codecs as for the audio tracks. Moreover, the video resolution differs from one video to another. This is the same problem for the audio codecs.

So my question are :

* What are the pre-requisities for merging 2 video mkv files ?

* Should they have to be encoded with the same audio/video codec and at the same rate ?

* Must they have the same resolution ?

Thanks in advance for helping me.
The thing that I would do is to encode all parts with the same x264 settings at the same resolution and then append it altogether in MKV.