[tebasuna51]

Originally Posted by MrVideo

Added tidbits...

eac3to declares the third-party MKV file's audio to be:

EAC3, English, 5.1 channels, 48kHz

No bitrate.
The ffmpeg generated file is listed as:

E-AC3, 5.1 channels, 1280kbps, 48kHz

Notice that the one that works is EAC3, while ffmpeg is E-AC3.

Is a know problem related with eac3to and EAC3 tracks in MKV container. It is not a ffmpeg problem.

Original file:

MKV, 1 video track, 1 audio tracks, 0:57:33, 24p /1.001
1: h264/AVC, 720p24 /1.001 (16:9)
2: EAC3, English, 5.1 channels, 48kHz "640 Kbps"
Bitstream parsing for track 2 failed. <WARNING>
Demuxing this track may still produce correct results - or not. <WARNING>

Recoded the EAC3 to EAC3 448 Kb/s with ffmpeg:

E-AC3, 5.1 channels, 0:57:33, 448kbps, 48kHz

Muxed in mkv:

MKV, 1 video track, 1 audio track, 0:57:33, 24p /1.001
1: h264/AVC, 720p24 /1.001 (16:9)
2: EAC3, English, 5.1 channels, 48kHz "448 Kbps"
Bitstream parsing for track 2 failed. <WARNING>
Demuxing this track may still produce correct results - or not. <WARNING>

Muxed in m2ts:

M2TS, 1 video track, 1 audio track, 0:57:33, 24p /1.001
1: h264/AVC, 720p24 /1.001 (16:9)
2: E-AC3, English, 5.1 channels, 448kbps, 48kHz

Without warnings.