Thread: Web Casts . . .
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Old 2015-05-15, 05:32 AM
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pawel pawel is offline
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Join Date: Dec 2004
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Re: Web Casts . . .

Let me add 2c as I am co-author of TTD rules on video

Quote:
Originally Posted by TriState View Post
UberDemon is right. There are no significant differences between a digitally captured HDTV broadcast and a digitally captured HD webcast.
No, in most cases there is a big difference, at least for materials coming from Europe: TV video bitrate is higher but at least 50%. Audio: vary. Have in mind that many webcasts have audio compressed (AAC) to and often below 160 kbps and sampling frequency 44.1 kHz, which is much worse than i.e. (minimum) Dolby Digital (AC3) 190 kbps / 48 kHz. Most digital TV broadcasts compress audio to 384 or 448 kbps and always at 48 kHz.

I wouldn't give a shit to a webcast which has 128 kbps AAC.

Quote:
Originally Posted by TriState View Post
Both situations are capturing a lossy video (and often lossy audio) source and writing it to a container (like mkv).
Audio is always lossy. None TV nor streaming site offer audio in uncompressed PCM format nowadays. Uncompressed TV audio comes from the analogue era of broadcasts and captures - gone since late 90's. Of course there are re-captures of old VHS tapes which have audio in wave format, and mandatory sampled at 48 kHz.

Quote:
Originally Posted by TriState View Post
Rewriting the rules to state a minimum bitrate, resolution, and lineage requirements would be a much more rational approach.
Agree. However, there always be a problem with some webcasts. I don't know why but AAC audio format not always provides info about its bitrate - none program I know returns the data. Then, except your ears, the only possibility to check how much it is compressed is to see its spectral frequency graph.
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BTW: it would be nice to include in this discussion Digital Audio Broadcast (DAB) as it is the same issue like webcasts vs. TV. I prefer DAB captures of 320 kbps/48 kHz over analogue FM > digital > flac. DVB-T/DVB-S DABs are less noisy, and often have better dynamic range than off-air captures.

Cheers,
Pawel
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