SpEeDaMiGo
12th June 2003, 20:58
First of all, I love AC3 5.1 sound and what I really appreciate about it is the possibility of playing it back in a compressed or dynamic mode, which are both supported by my external decoder.
Now, I mostly use AC3Machine just to lower the bitrate a bit (eg. 448 to 384) when the compressibility of the movie doesn't allow for big 448kbit files. So I always do a "clean" transcode, i.e. any option like DRC or gain or whatever disabled, just lowering the bitrate for the new 5.1 file. Unfortunately the dynamic range information somehow gets lost in this process, which means the resulting AC3 file won't feature its two original modes any more, which is a real pitty.
I've compared the original AC3 stream and the transcoded one on a audio-only-file basis in WinDVD and on a muxed (ogg) basis and the result is the same: switching dynamic mode on and off on my decoder won't make any difference at all with the transcoded file.
So it seems like the compression flags or whatever part responsible for the dynamic information in the AC3 stream get lost in the transcoding process.
Any ideas or suggestions on this would be great, thanks. Sorry if my search didn't go deep enough or if it happens to be a configuration mistake.
I've done quite many transcodings so far showing the same problem which I somehow just didn't notice any earlier.
Although checked, the besweet logfile doesn't show anything about AC3Machine so here my command line (just to illustrate the "clean" transcoding):
"C:\Program Files\Ripping\Gordian Knot\BeSweet.exe" -core( -input "D:\XXX\xxx AC3 T01 3_2ch 448Kbps DELAY 0ms.ac3" -output "E:\xxx - 384 0ms.ac3" -logfilea C:\Program Files\Ripping\Gordian Knot\BeSweet.log -substream SubS ) -ac3enc( -b 384 ) -profile( The AC3Machine v0.4 )
Now, I mostly use AC3Machine just to lower the bitrate a bit (eg. 448 to 384) when the compressibility of the movie doesn't allow for big 448kbit files. So I always do a "clean" transcode, i.e. any option like DRC or gain or whatever disabled, just lowering the bitrate for the new 5.1 file. Unfortunately the dynamic range information somehow gets lost in this process, which means the resulting AC3 file won't feature its two original modes any more, which is a real pitty.
I've compared the original AC3 stream and the transcoded one on a audio-only-file basis in WinDVD and on a muxed (ogg) basis and the result is the same: switching dynamic mode on and off on my decoder won't make any difference at all with the transcoded file.
So it seems like the compression flags or whatever part responsible for the dynamic information in the AC3 stream get lost in the transcoding process.
Any ideas or suggestions on this would be great, thanks. Sorry if my search didn't go deep enough or if it happens to be a configuration mistake.
I've done quite many transcodings so far showing the same problem which I somehow just didn't notice any earlier.
Although checked, the besweet logfile doesn't show anything about AC3Machine so here my command line (just to illustrate the "clean" transcoding):
"C:\Program Files\Ripping\Gordian Knot\BeSweet.exe" -core( -input "D:\XXX\xxx AC3 T01 3_2ch 448Kbps DELAY 0ms.ac3" -output "E:\xxx - 384 0ms.ac3" -logfilea C:\Program Files\Ripping\Gordian Knot\BeSweet.log -substream SubS ) -ac3enc( -b 384 ) -profile( The AC3Machine v0.4 )