Software for conversion, output AC3

[lenberg]

Hi everyone
I would like to convert the audio of some mkv movies. The audio is mainly in DTS 5.1 format, but some are in truehd format or dtshd. I have a set of 2 front speakers and a subwoofer. My amplifier is old and only understands Dolby Digital. So I need a software to convert those audios to Dolby Digital. Is it possible to go from DTS 5.1 to Dolby Digital AC3 2.1? (2 - front left and right and .1 - subwoofer)
Thank you.

[ricardouk]

Open the mkv in avidemux and select:
1- Video output -> copy
2- audio output -> ac3 (aften or lav), select CONFIGURE and FILTERS to your liking
3- output format ->mkv
4- File -> Save

Or load the mkv video file in LameXP and convert the audio to ac3, then use avidemux to add that audio track to the original mkv, that way you'll have both dts and ac3

or use a "one in all converter" like vidcoder, xvid4psp, format factory, tencoder etc

[lenberg]

Thanks for the reply. I installed avidemux and now I really don't know which filter I should choose for 2.1 (2 front speakers + subwoofer):

stereo
stereo + surround
stereo + center
stereo + center + surround
stereo front +stereo rear
Dolby Prologic
Dolby Prologic II

[sneaker]

What is your player? If you are using your PC for playback: some software players allow on-the-fly re-encoding to AC3. Then you don't have to go through the hassle of re-encoding everything.

[lenberg]

My player is a popcorn hour vten

[lenberg]

None of the options that avidemux offers gives me the option for 2.1
Only if I choose 5.1 it keeps the LFE channel... (according to mediainfo)
The rest give me combinations of FL and FR, FL C FR... Mediainfo doesn't mention LFE in these. But then the subwoofer is not doing anything?

[netmask56]

Popcorn Audio Convertor can convert DTS to AC3 Dolby digital and downmix to stereo in one operation without affecting or processing the video and in situ

https://www.videohelp.com/software/PopCorn-MKV-AudioConverter


[Attachment 45830 - Click to enlarge]

[pandy]

It may be a plain stereo configuration when subwoofer part is extracted from Left and Right in analog filter and redirected to sub - you should verify this and this is why i prefer to manually always add LFE to downmix part. And by Dolby standard LFE downmixing is not forbidden - it is just not recommended to avoid clipping but if you can prevent clipping then everything is fine.

[lenberg]

Popcorn Audio Convertor can convert DTS to AC3 Dolby digital and downmix to stereo in one operation without affecting or processing the video and in situ

https://www.videohelp.com/software/PopCorn-MKV-AudioConverter


[Attachment 45830 - Click to enlarge]

I tried with this software, but according to mediainfo there is not any LFE channel in the resulting file, only L and R

It may plain stereo configuration when subwoofer part is extracted from Left and Right in analog filter and redirected to sub - you should verify this and this is why i prefer to manually always add LFE to downmix part. And by Dolby standard LFE downmixing is not forbidden - it is just not recommended to avoid clipping but if you can prevent clipping then everything is fine.

How do you manually add LFE? Are you referring to Popcorn Audio Converter software? Thank you

[netmask56]

What type of speakers do you have, ie physical size of the cones of the main speakers and what type of subwoofer is it - amp output etc. The LFE channel is derived from the discrete left and right channels anyway. Depends on if you amp filters out low bass on the L and R speakers or merely adds a low pass mix of the L and R to the sub amp and speaker. Nothing discrete about the info on the LFE it's all there on your L and R speakers and if they are up to the job you don't need the sub but it does depend on the speakers themselves.

[lenberg]

Drivers

Front : 2.5 inch
Subwoofer: 6 inch

Dimensions

Front: 89 mm (W) x 89 mm (H) x 89 mm (D)
Subwoofer: 250 mm (W) x 204 mm (H) x 375 mm (D)

I don't know much about technical details of the system. The subwoofer doesn't have any power adapter, it is only connected to the amplifier with a cable. The speakers don't have a power adapter either.

*Note: The previous owner is looking for the center speaker so I may get hold of it. Maybe in that scenario I have more conversion options...

[pandy]

How do you manually add LFE? Are you referring to Popcorn Audio Converter software? Thank you

My comment was related to manual downmixing - never used mentioned by you converter as such can't help you directly. Personally prefer to use ffmpeg where i usually performing custom downmixing with LFE.

pan=stereo|FL < FL+1.414FC+0.5BL+0.5SL+0.25LFE|FR < FR+1.414FC+0.5BR+0.5SR+0.25LFE

Such downmixing allow me emphasize center (dialogue) channel and not loose signal from LFE channel.

[lenberg]

pan=stereo|FL < FL+1.414FC+0.5BL+0.5SL+0.25LFE|FR < FR+1.414FC+0.5BR+0.5SR+0.25LFE

Thank you for the reply.
How would you include in that line of parameters the center speaker? (I may get hold of one soon) So it would be FL FC FR and subwoofer.
That way the center would carry mainly the dialogues and other effects and music would come from the FL and FR, and with a moderate sound in comparison to the dialogues so we don't go deaf when there is an explosion.

Thank you.