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2nd October 2020, 11:57 | #15021 | Link |
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To view AC3 metadata you can use MediaInfo or my LeeAudBi tool.
I don't know other tool to edit AC3 metadata, only eac3to for set DN to -31dB or specific tools for instance the attached ones: - DN27_Ac3 restore the Dolby DN default value to -27 dB (a decoder Dolby compliant must attenuate in 4dB the full stream by default) - DN31_Ac3 remove the DN, setting the value to -31 dB (a decoder must decode without attenuate nothing, recommended for recode in ac3to by default) - DplAc3 set the Dolby Pro Logic flag in stereo AC3's I don't know other metadata than can be safely changed without recode. BTW there are here (now DN work also with EAC3)the sources to do other changes.
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BeHappy, AviSynth audio transcoder. Last edited by tebasuna51; 29th September 2021 at 16:48. |
2nd October 2020, 12:05 | #15022 | Link | |
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2nd October 2020, 12:46 | #15023 | Link | |
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Quote:
https://forums.stevehoffman.tv/threa...urround.63579/ https://forums.stevehoffman.tv/threa...ls-play.45319/
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2nd October 2020, 12:51 | #15024 | Link |
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It is difficult because DRC info is provided in audioblocks (6 for each frame) not with common metadata in BSI (Bit Stream Information) header frame info.
All decoders can be instructed to ignore DRC (or apply only a part). You can recode these ac3 streams with ffmpeg and -drc_scale 0
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11th October 2020, 17:14 | #15026 | Link |
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I delayed the audio 400ms but the program copied part of the previous dialog. The silence should start at minute 22:25:780, why does this happen?
https://imgur.com/Vtt9exm.jpg |
12th October 2020, 18:32 | #15028 | Link |
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Thank you. I tried that and the program cuts the last part of the dialogue and moves it forward. I don't understand why the program doesn't create a silence from the exact point.
https://imgur.com/OGOspPl.jpg |
17th October 2020, 09:17 | #15031 | Link | |
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Quote:
https://gitlab.com/mbunkus/mkvtoolnix/issues/2377 |
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17th October 2020, 12:13 | #15032 | Link | |
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Yes, in MKVToolNix GUI -> Preferences -> Default values we can "Enable dialog_normalization gain removal for audio tracks" But maybe the correct text was: "Enable dialog_normalization attenuation removal for audio tracks" because enabling the removal we obtain a more loud track. Remove the Dialog Normalization in a AC3 track means put -31 dB in the field of each header. A standard value is -27 dB than say to decoders dolby compliants attenuate the track by 4 dB (-27-4=-31)
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BeHappy, AviSynth audio transcoder. Last edited by tebasuna51; 20th October 2020 at 12:09. Reason: typo |
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20th October 2020, 07:35 | #15033 | Link |
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As explained in chapter 6 of this document...
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2nd November 2020, 01:10 | #15035 | Link |
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To compare two files to see if are bit-identical you can use the MSDOS command line:
FC /B file1 file2 (FileCompare /binary) But, of course, if the files are encodes from different encoders it is improbable obtain the same file.
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2nd November 2020, 01:17 | #15036 | Link |
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Both files were encoded with two different officially "certified" encoders so I am trying to see if there is any difference between them. They are otherwise identical, same exact file size and spectogram.
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2nd November 2020, 08:27 | #15037 | Link |
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To compare the decoded video content, you can open both clips in AviSynth and use some comparing functions (Subtract creates a visual difference which you can enhance with Levels, and Compare writes statistics to a CSV file). Also there are video comparing applications (like Fritz Framalyzer). But that does not compare the video bitstreams, which may differ in details (e.g. timestamp values) but still decode to identical videos.
But why do you ask that in a thread about eac3to, which is an audio-only converter? |
2nd November 2020, 10:26 | #15038 | Link | |
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2nd November 2020, 10:59 | #15039 | Link |
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Oh, then I misunderstood, sorry ... but in one regard, the same applies to audio just as to video: Files may have slight differences in metadata, even widely different compressed bitstreams (depends on the used audio format and its encoding algorithm), yet would produce identical decoded results.
Audacity seems to have a CompareAudio function for two tracks. Or you can use the hash muxer in ffmpeg (note that it would return different hashes if compressed audio uses block lengths and the number of samples differs). |
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