H265(HEVC) to H264 without loss of audio quality?

[pauljuhn]

Hi,
I am converting a H265 video file(MKV) to a MP4 H264 file as my media player can't handle H265 file.
To me, sound quality is more important than video quality.
How can I be sure that the audio part is intact when conversion finished?
I use Aimersoftvideo converter ultimate and there is a parameter to choose from - "keep original".

Is it technically possible to keep original for audio when converting video - especially from H265 to H264?

Another question is that the file size becomes bigger(which is natural) than original in this conversion.
But not always and sometimes it becomes smaller - This does not make sense to me.

[Gravitator]

Привет!
You need to use direct transfer of audio tracks (without conversion / encoding). I prefer to use the utility MKVToolNix in such cases.

[pauljuhn]

Hi Gravitator,
Can you please explain in detail? I can see those audio and video file from the MKVTollNix.
Should I separate audio file from it and replace with it in MP4 H264 ? how? Thanks!

[teodz1984]

H265 sometimes is more compact than H264, assuming same bitrates... so converting would enlarge the target file
Use programs like HANDBRAKE convert video part to h264
but just copy audio track only on that same program options

[Gravitator]

1 Add both video files to the program (they will be displayed in the window labeled "Source files:");
2 Remove the tick from unnecessary video and audio stream / track (the operating table is called "Tracks, chapters and tags:");
3 Choose a place to save the result of work ("Destination files").
4 Start MULTI-PLEXING (the program will unify the selected audio and video streams in the *.mkv container).
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I hope the religion of your player will reproduce the .mkv container.

[dannyboy48888]

As mentioned handbrake and use audio passthru, used it on ac3 and AAC tracks and it did just that. Just be sure to unclick burn in subtitles