Hi everyone , i want to merge multiple videos in a...

# android

[Harpreet Singh.8052]

Hi everyone , i want to merge multiple videos in android . Is it possible using Media3 for that

[gildor]

No, media3 doesn't have any video creation things, only playback them

[Vivek Choudhary]

Ffmpeg library does that

[Harpreet Singh.8052]

I used ffmpeg but take so long to process I tried merging 10 video of 1min and it took 10min to process

[Harpreet Singh.8052]

https://medium.com/google-exoplayer/trim-transcode-concatenate-your-guide-to-media3-editing-libraries-668b4e4c2f97

[gildor]

There are 2 main options: ffmpeg or use video codex directly, second one is way more challenging to do right

I would suggest to check with ffmpeg, looks what you are doing does full re-encoding of videos, which may be what you need or not, depending on source videos

For media3 I was not aware that they added those features, I believe they use Android video codex directly under the hood

[Harpreet Singh.8052]

To prevent re-encoding we use -copy , but for merging the frame rate should be same of every video

[gildor]

yep, exactly

[Harpreet Singh.8052]

But if the frame rate bis different we need to use sink

[Harpreet Singh.8052]

-vsync

[gildor]

so if videos are different, you have to re-encode them, which is slow

[gildor]

Reducing output video bitrate/resolution may be in option
But I wouldn't expect magic from native hardware execrated one too

[Harpreet Singh.8052]

I cannot compromise video quality, even though you r right reducing bitrate speed up the process

[Harpreet Singh.8052]

But I'm wondering how video editing app does that , they have lots of feature , capcut , kinemaster and they won't take that long to process output

[gildor]

well, they work with codecs directly, a bunch of work is put there to optimize

[gildor]

Also ffmpeg is not a codec, there are different codecs there, they have different results, also depending on how you build it

[gildor]

video is hard

[Harpreet Singh.8052]

Using codec directly talking to hardware , is this a. Hard concept for a beginning?

[gildor]

Not directly, it's not correct, there is MediaCodec API, it's fully abstracted from hardware and even from specific codecs

But doesn't make it easy anyway, it's still require a lot of knowledge how it works and still need a lot of handling to work on all/many devices

[gildor]

I just found our benchmarking, comparing
libx264
libopenh264
libx265
MediaCodec

Just for your information:
result of encoding 20 second video on three phones with arm64 architecture:

Bit rate: 400000
Frame rate: 25
Width: 640
Height: 480

Encoding with: libx264
FrameCount: 501
Encoding time: 2678877 (2.7 sec)
Encoded size:: 1042868 (1.0 MB)

Encoding with: libopenh264
FrameCount: 501
Encoding time: 3030407 (3.0 sec)
Encoded size:: 1926019 (1.9 MB)

Encoding with: libx265
FrameCount: 474 ← it drops frames
Encoding time: 68466158 (6.8 sec)
Encoded size:: 985413 (990.6 KB)

Encoding with: native
FrameCount: 501
Encoding time: 12867000 (1.29 sec)
Encoded size:: 1002592 (1.0 MB)

Other phones give different results, but native codec always faster

[gildor]

So, I would try media3 abstraction, looks very similar to what we built under the hood in our application

[Harpreet Singh.8052]

Thanks for the detailed explanation

[Harpreet Singh.8052]

Hey i used media3 's transformer it use mediaCodec , i tried merging 2 video of size 1 minutes , and it took around 1min20sec to merge , fastet then ffmpeg it took 2 minutes , few seconds less if I use libx264

[gildor]

yes, that what I would expect

[Harpreet Singh.8052]

Thinking of reducing frame rate before merge to 24 , it's current 30

[gildor]

I think first thing to do is fine lowest resolution and bitrate from all videos and set output format accordingly

[Harpreet Singh.8052]

Video is recorded from the mobile camera

[Harpreet Singh.8052]

It's same bitrate or fps for every video

[gildor]

Isn't in this case it should be possible combine them without full re-decoding? Because videos from the same device should have same resolution, codec and frame rate

[Harpreet Singh.8052]

yes , but how can i do that

[gildor]

I would expect that even ffmpeg could do this, for media3 not sure about their internal logic, but maybe if just match input configs with output

[Harpreet Singh.8052]

Ffmpeg -i first.mp4 -i second.mp4 concat "something video audio related " output.mp4

[Harpreet Singh.8052]

This is the basic command for merging video but it take time in android ,

[gildor]

I don't think it's so simple, but may be, depends on ffmpeg implementation for it