FFAStrans forum

I'm interested in only transcoding the video of a file and maintaining the original audio, regardless of what tracks are included. I've tried setting up the h264 encoder with my video transcoder settings, which works as expected.

On the h264 encoder, for audio I select: Layout: same as source, Sample Rate : 48000 and BitRate: %i_a_bitrate% (original bitrate as source file)

The result is, confusing.

Original:
ID : 2
Format : DTS
Format/Info : Digital Theater Systems
Format profile : ES Discrete / Core
Codec ID : A_DTS
Duration : 2 h 4 min
Bit rate mode : Constant
Bit rate : 1 509 kb/s
Channel(s) : 7 channels / 6 channels
Channel positions : Front: L C R, Side: L R, Back: C, LFE / Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : 24 bits
Compression mode : Lossy
Stream size : 1.31 GiB (11%)
Language : English
Default : Yes
Forced : No


Transcoded:
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : mp4a-40-2
Duration : 2 h 4 min
Bit rate mode : Constant
Bit rate : 463 kb/s
Channel(s) : 2 channels
Channel(s)_Original : 7 channels
Channel positions : Front: L C R, Side: C, Back: L C R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 413 MiB (9%)
Default : Yes
Menus : 0

It looks to me as though I've lost the DTS-ES surround from the original.

Is there a way to transcode only the video and retain the original audio? Been looking at the custom FFMPEG encoder, concerned about unchecking the audio transcode as there may not be any audio in the transcoded file.

Hello clking,

Well it's quite simple and you have to use a custom ffmpeg node. Uncheck video and audio, remove "-ac 2" (usefull for stereo) and type the video settings that you want first:
f ex : -c:v libx264 (for h264 codec)-b:v 6000k (for 6000k bitrate) -c:a copy (to copy all audio streams)

It will be ok now.

Cheers.
B.

Thank you B., this is the direction I thought I'd need to go, just wanted that confirmation. I love FFASTrans for the automation it offers but struggle a bit with the documentation (though it is still good.)

This community is a great asset and continues to provide fantastic information.