[FFmpeg-user] DTS 7.1 to AC3 5.1

[Mark Filipak]

On 22/05/2025 16.07, Paul B Mahol wrote:
> On Thu, May 22, 2025 at 8:01 PM Mark Filipak <markfilipak.imdb at gmail.com>
> wrote:
> 
>> Hi, All,
>>
>> I've tried every trick in the documentation but I can't persuade FFmpeg
>> CLI to convert DTS 7.1 to
>> AC3 5.1.
>>
>> The best I get is AC3 5.0(side).
>>
>> Handbrake does it, and it uses the same libraries! I went ahead and made a
>> minimal-resolution, MPEG2
>> copy just to get at the AC3 5.1.
>>
>> Do you do DTS 7.1 to AC3 5.1 via FFmpeg? How do you do it?
>>
>>
>>         silent = 3,214,906,938 bytes
>> with DTS 7.1 = 8,623,235,367 bytes
>> with AC3 5.1 = 3,968,811,052 bytes
>>
> 
> Use librempeg instead:
> 
> ffmpeg -i 7_1.m2ts -af acl2cl=5.1 -vn x.ac3

Thank you, Mr. Mahol. 'acl2cl' is not documented. But I will try it.

The try will likely fail because 'librempeg' appears to be lacking in Mr. Doshi's builds. Hopefully, 
I'm wrong about that.