crusher11 1101 Posted August 22, 2019 Posted August 22, 2019 I'm watching Breaking Bad, and some of the conversation is super quiet so I turned on subtitles. This obviously requires the video to be transcoded to burn them in, but it also changed the audio from the original DTS to AC3. Why can't it simply transcode the video and mux it with the original audio?
Happy2Play 9780 Posted August 22, 2019 Posted August 22, 2019 Please post the corresponding server and ffmpeg logs.
Luke 42077 Posted August 22, 2019 Posted August 22, 2019 Because the transcoding format can't carry DTS so the audio has to convert as well.
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 Why can't it transcode into something that can carry DTS?
Luke 42077 Posted August 22, 2019 Posted August 22, 2019 There isn't really a suitable option for that.
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 Why not? The format it's originally in can handle DTS, why can't it transcode into that format?
Luke 42077 Posted August 22, 2019 Posted August 22, 2019 The HLS streaming protocol does not support DTS.
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 What's the "HLS streaming protocol"?
Luke 42077 Posted August 22, 2019 Posted August 22, 2019 https://www.dacast.com/blog/hls-streaming-protocol/
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 But how does that tie in to this specific context?
Happy2Play 9780 Posted August 22, 2019 Posted August 22, 2019 But how does that tie in to this specific context? The delivery method changed when you add I assume unsupported subtitles and that method required the audio track to be changes also.
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 But I'm still not seeing why the remux can't use the original delivery method.
Luke 42077 Posted August 22, 2019 Posted August 22, 2019 Because the original delivery method is a completed static file. When you have to convert on the fly that's no longer the case. I assume you don't want to wait for the entire file to be converted, so we use a streaming protocol that allows us to send small chunks at a time. 1
Happy2Play 9780 Posted August 22, 2019 Posted August 22, 2019 (edited) But I'm still not seeing why the remux can't use the original delivery method. You have not provided the ffmpeg log so we don't know exactly what is going on. But the file is not being remuxed anymore it is being converted/transcoded. Edited August 22, 2019 by Happy2Play
rbjtech 5284 Posted August 22, 2019 Posted August 22, 2019 If you want to maintain the original video and DTS audio - then use an external subtitle text file (.srt) - then it would most likely not need to transcode in the first place... 1
Happy2Play 9780 Posted August 22, 2019 Posted August 22, 2019 That is where I was headed but did not know the specifics of this transcode session.
crusher11 1101 Posted August 22, 2019 Author Posted August 22, 2019 (edited) It's PGS from the BDs. I'm aware that requires the video to be transcoded, I just didn't understand why it would affect the audio. Because the original delivery method is a completed static file. When you have to convert on the fly that's no longer the case. I assume you don't want to wait for the entire file to be converted, so we use a streaming protocol that allows us to send small chunks at a time. This is the sort of explanation I was looking for, thanks. Edited August 22, 2019 by crusher11
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