madshi bug tracker - eac3to
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0000373eac3tobugpublic2015-12-29 16:392016-11-24 02:50
shr3k 
 
normalminorhave not tried
newopen 
3.31
0000373: AC3 encoder delay
Hi, a some time ago I found that AC3 encoder in eac3to produces some delay in output file. With comparison in Audacity it can be compensated by adding -5ms to command line (produced AC3 will be still 16 samples at 48 kHz behind the original source).
Take some sound file. Encode it to AC3. Decode it to FLAC. Open in Audacity and compare waveform.
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zip delay.zip (927,678) 2015-12-29 16:39
http://bugs.madshi.net/file_download.php?file_id=189&type=bug
Issue History
2015-12-29 16:39shr3kNew Issue
2015-12-29 16:39shr3kFile Added: delay.zip
2016-11-24 02:50tebasuna51Note Added: 0001503

Notes
(0001503)
tebasuna51   
2016-11-24 02:50   
All encoders, even commercial ones, produce a delay in output because need initialize the soft and send a initial silence before send the input audio.

AC3 encoders send 256 PCM samples of silence, at samplerate 48000 is 5.333... ms

A workaround using Aften encoder is use the parameter -pad 0, but don't know a equivalence using ffmpeg.

BTW the problem is not related with eac3to but with each encoder.