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Topic: Do Youtube & others transcode over and over?  (Read 4696 times) previous topic - next topic
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Do Youtube & others transcode over and over?

I realize that I am going to invite to speculations, but anyway. I assume I won't get a TOS#8 knocking if I say that there are quite a few bad-sounding Youtubes around. I have always assumed that this is due to low-bitrate uploads (I guess users get a video from Youtube, edit it, and convert it to low bitrate so they won't have to wait forever for it to upload) - but could it be repeated transcoding by the service itself?

- Take Youtube then. Youtube offers several audio and video formats, and they have changed numerous times. Does Youtube keep the original upload, or has it been transcoded once upon upload and at least once more later? 
- What about other competing services - Dailymotion, Vimeo, ... ?
- IIRC, Myspace (remember that?) used mp3 in the past, didn't they? As far as I can tell, they use AAC exclusively by now. Have they transcoded everything?

Re: Do Youtube & others transcode over and over?

Reply #1
I had a youtube account "ac252c" few years ago, focused by uploading some of my game music transcriptions and re-arrangements, but later I deleted the account for various reasons, one of them is some people constantly asked me to upload the MIDI or DAW project file I used in my videos. In the past I didn't mind and I also have some files uploaded to vgmusic.com. But later I found some people re-rendered some of my MIDI files by using other instruments and claimed they created them. I was extremely frustrated as their videos even have more views than mine.

Some people were honest/kind enough to credit me in the video description though, like this one:
https://youtu.be/RzJUlWMonaQ

My "style" is never loop a tune more than necessary, some people prefer longer loops so this youtube user for example, extended the tune and re-upload them. So the original source of this video is definitely based on my youtube upload. I uploaded the audio as lossless at that time and let youtube transcode it.

I keep the original file as float 32 wavpack, encoded it to 202kbps fhg aac and attached here, it should be transparent enough as a reference to compare with the youtube video above.

In my experience, youtube accepts lossless video/audio upload as long as the container supports them, but they will transcode them to lossy, I couldn't find a single exception. If you upload a lossy source, they will also transcode them to lossy once again. I didn't use the web-based video editor though.

Another video sharing site, nicovideo.jp will not transcode your video/audio when certain conditions are met, it related to target file size, bitrate, resolution, and codec format. At most time it is the best method to upload the highest possible quality video/audio in nicovideo so a member with adequate knowledge will usually following the "formula". As a result it also puts less burden on the server side since they don't need to encode stuff so often.

Re: Do Youtube & others transcode over and over?

Reply #2
Yes they transcode all uploads. Size over quality is the name of game and many 'Full HD' vids can show artifacts while your old DVDs are fine...Just not as sharp.  Audio also gets transcoded to 128k aac or lower depending on the video profile chosen.

Audio is also affected some are pretty obvious. I guess if its from a HQ upload source like a record company the results are better to my ears than some random user.

Re: Do Youtube & others transcode over and over?

Reply #3
Surely they transcode if you upload in a different format - the question is whether they transcode again upon changing format. (They are rolling out Opus now, but I did not (yet?) see Opus on old files?)


Re: Do Youtube & others transcode over and over?

Reply #5
Surely they transcode if you upload in a different format - the question is whether they transcode again upon changing format. (They are rolling out Opus now, but I did not (yet?) see Opus on old files?)
That is something I also would like to know. Would be a bit dumb to not keep the original audio IMO.

Re: Do Youtube & others transcode over and over?

Reply #6
They need the original files also for new video encodes (VP8, VP9, AV1). It wouldn’t be very good to use VP8-copy to make a VP9-copy, or a VP9-copy make an AV1-copy etc.
Rhythmbox, Flac + Vorbis, Sennheiser HD650 + Sony MDR-XB1000

Re: Do Youtube & others transcode over and over?

Reply #7
IIRC, years ago when I uploaded some AVI files to Youtube, it would let me download my original AVI files (if I was logged in to my account).
I think it's extremely unlikely that they delete the original files. It would be a silly thing to do and I doubt Google employs silly people like that.

Re: Do Youtube & others transcode over and over?

Reply #8
Remember the fmt18/22 trick in the past?
https://youtu.be/tOAio-LEQyI

I am pretty sure they keep the original. I uploaded some screen capture videos at 1280*1024 in the past in my deleted account when youtube was still using 360p. As youtube upgraded higher resolutions became available.

The Final Fantasy video in my previous post offers 162kbps opus for example, and it was uploaded in 2010.

Re: Do Youtube & others transcode over and over?

Reply #9
Youtube keeps all original uploaded files for the videos it serves. This can be easily confirmed by trying to download an account's file backup. I did it once, long ago, and don't remember how I did it, but it shouldn't be hard to find. I was surprised to find all my videos in their original formats.
I'd assume that, when they implement any new codec, the systems transcodes from the original file again, instead of the current transcodes they use for streaming. I mean, that'd make the most sense.

Re: Do Youtube & others transcode over and over?

Reply #10
https://takeout.google.com/settings/takeout

Last time I attempted this, it made a big zip file with all my data from all google services. I guess it can get ridiculously big. Maybe it does multi-part or multiple archives.

Re: Do Youtube & others transcode over and over?

Reply #11
https://takeout.google.com/settings/takeout

Last time I attempted this, it made a big zip file with all my data from all google services. I guess it can get ridiculously big. Maybe it does multi-part or multiple archives.
I just tried it and I got my original unaltered uploads :)
It would be nice if they included a feature in YouTube itself to do this.

Re: Do Youtube & others transcode over and over?

Reply #12
IIRC, YouTube does keep the original uploaded file as a "master," but all the actual streams the end user is presented with are transcoded according to a specific configuration.

Re: Do Youtube & others transcode over and over?

Reply #13
Youtube seems to be settled (at doing the right thing). What about e.g. Myspace?
Anyone who remembers anything about that place?