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  1. Member
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    Hi Guys,

    I`m Newbie and would like to know about conversion the audio.

    I extracted (Demux) sound from my Blu-ray. The original codec is DTS. Because my SmarTV LG is not compatible, so after demux, I converted to AC3 and remake the MKV. I Used "Pazera Free Audio Extractor" to convert DTS to AC3.

    The bitrate of original file (DTS) was 768kb/s (242 MiB) and when i converted, the AC3 file had bitrate 640 Kb/s (201 MiB).

    The Question:
    1) Everytime that I will convert some audio, i will lost quality?
    2) Is possible to do a conversion without lost quality and permanence the original sound?
    3) If is possible, what is the program/app can I use?

    Thanks and sorry for my english....
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  2. Member Cornucopia's Avatar
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    1. If you are converting (re-encoding) to a/another lossily-compressed format (e.g. AC3, DTS, AAC, MP3, OPUS) you WILL lose quality every time.
    How much, depends on the codec/format, and the settings (especially bitrate).

    2. When you DECODE your original, that is the best it can be. From there, if you re-encode uncompressed (e.g. LPCM, DSD) or losslessly-compressed (e.g. FLAC, MLP/TrueHD, DTS-MA, ALAC), you will NOT lose any further quality.
    *Note: there is some slight loss if during these changes you also do sample rate conversion, bit depth conversion, remixing, etc. Regardless of lossy or lossless/uncompress format.

    3. Look in the software listings above. There are a number of possibilities (ffmpeg, sox, eac3to, etc), both free and paid.

    Scott
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  3. Member
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    Scott,

    If i understood

    1) If i decode from DTS original file and after re-encode to AC3, I will NOT lose?
    2) How I do this? What is the name of extension after decode?

    I don`t know the command to do

    Thanks
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  4. Member hech54's Avatar
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    Originally Posted by caemilani View Post

    1) If i decode from DTS original file and after re-encode to AC3, I will NOT lose?
    Yes you will lose quality.
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  5. Member Cornucopia's Avatar
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    Let’s be clear: the DTS may be original to your rip but it is not the true original master.
    Likely that was an LPCM WAV or similar.
    The DTS is already compressed (lossily) so it already has incurred loss of quality.
    Decoding it does not restore the original but instead the nearest possible facsimile, based on the bitrate and other settings of the DTS encode.
    Any re-encoding is now based on and starting from that facsimile (at that point, the DTS doesn’t enter into it). And this cycle could repeat ad nauseum.
    Think: the Telephone game (https://en.m.wikipedia.org/wiki/Chinese_whispers).
    If that new format is lossy, you will lose quality (hence the name).
    AC3 is a lossy format.
    Thus...

    There are plenty of encoders that do AC3, including FFmpeg. The Vhelp site can guide you well so I won’t duplicate the info.

    Scott
    Last edited by Cornucopia; 22nd Feb 2018 at 22:45.
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  6. Member hech54's Avatar
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    Exactly. There are people who still think video and audio compressions work like ZIP files.
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  7. Video Restorer lordsmurf's Avatar
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    Originally Posted by caemilani View Post
    Because my SmarTV LG is not compatible
    The TV probably expects H.264 and AAC audio. Check the manual for specifics and required bitrate max/min.

    Originally Posted by hech54 View Post
    Exactly. There are people who still think video and audio compressions work like ZIP files.
    Lossless does, namely Huffyuv that uses Huffman encoding (ie same as PKZIP).
    Want my help? Ask here! (not via PM!)
    FAQs: Best Blank DiscsBest TBCsBest VCRs for captureRestore VHS
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