Adding silence to E-AC-3?

[luciofulci]

Hi all,

I have an E-AC-3 file and I need to add a couple of seconds of silence at the beginning of it - is this possible? From what I can see there are no E-AC-3 encoders. If not what would you suggest I do to achieve this with maximum quality? Unfortunately with this project I can't alter the video length.

This is the file info:

Audio
Format : E-AC-3
Format/Info : Enhanced AC-3
Commercial name : Dolby Digital Plus
Duration : 1 h 59 min
Bit rate mode : Constant
Bit rate : 640 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz

Many thanks

[sneaker]

ffmpeg can encode E-AC-3 (not sure if all flavors, though). Try something like:

ffmpeg -f lavfi -i "anullsrc=channel_layout="5.1(side)":sample_rate=48000" -to 03.264 -b:a 640k "silence.eac3"

(3 seconds 264ms silence in this example)

[luciofulci]

That's great! Thanks sneaker much appreciated.

I've done that a made my silence eac3 for the correct time. Just one more question (I've never used ffmpeg before) how would I join this new file and my other audio file together as one eac3 file?

[sneaker]

Not sure if this allowed (headers?) but try:

copy /b "silence.eac3" + "rest.eac3" "output.eac3"

(or similar)
https://docs.microsoft.com/windows-server/administration/windows-commands/copy

[luciofulci]

Thanks I'll give that a go.

[luciofulci]

No luck I'm afraid, however I did just find this in the eac3to guide where it shows examples:

• Delay an E-AC3 track by +178ms:
eac3to input.eac3 output.eac3 +178ms

I'll test it later and see what happens.

[hello_hello]

Try MKVToolNixGUI. Use it to append the two eac3 files and mux them as a single mka, then use something like gMKVExtractGUI to extract the single audio stream as eac3 again.

[luciofulci]

I had been a bit sidetracked but just tested the eac3to command 'eac3to input.eac3 output.eac3 +178ms'. This actually works perfectly. Thanks hello_hello for the other option though.