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Show HN: YTPics – Download pictures from YouTube videos

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Re: Show HN: YTPics – Download pictures from YouTube videos

#31

Post by thrdbndndn »

vitehozonage wrote: post #25
web0_cc wrote: post #19

Earlier quoted context omitted.

yt-dlp ${youtube_video_url} --get-url ffmpeg -ss ${seconds} -i "${first_url_from_yt-dlp}" -t 1 -r 4/1 -q:v 2 -vf scale="0:-1" ${target} -r 4/1: 4 frames per second Again this app is for mobile devices which lack yt-dlp+ffmpeg

Does this really not download the whole video? I havent checked but im just surprised that it's possible

No it doesn't. FFMPEG can seek video directly without loading all the content, even for Dash/HLS (but in this case yt-dlp typically returns a plain HTTP source, which I assume internally FFMPEG uses HTTP header range to seek?)

Keep in mind you need to make sure to use input seeking, though (-ss before -i).

Also I'm not sure why they need `-vf scale="0:-1"` part.

Re: Show HN: YTPics – Download pictures from YouTube videos

#33

Post by abrugsch »

darrenf wrote: post #3

By "pictures" does this mean individual frames? FYI on desktop using an up to date Chrome, you can right click twice – slowly, not a double-click – and choose "Save video frame as..." (on macOS, at least)

Also works on Windows, Firefox (labeled as "Take Snapshot" though)

Re: Show HN: YTPics – Download pictures from YouTube videos

#34

Post by teitoklien »

Beijinger wrote: post #14

I have extracted frames with vlc before before. They always look like shit. Like with a lower resolution. Why? Like if you freeze a youtube video the pic looks clean.

During streaming, lower res image frames are sent, to avoid buffering as much as possible, depending on your internet speed the res increases or decreases

When you stop the frame, the video can download the highest res version without any problem, so you get crystal clear glimpse when paused, but blurry images when film is rolling.

Re: Show HN: YTPics – Download pictures from YouTube videos

#35

Post by Arelius »

SamBam wrote: post #32

Do any armchair lawyers (I know, I get what I pay for) want to chime in on the legality of creating user-definable 3-5 second gifs of YouTube videos, which link back to the video in question, for an online video curation library thing?

I mean, you will almost certainly be in a constant state of creating material in violation or copyright. Depending on the details of any specific copyright violation, it may be protected by Fair-use, and the length and lack of audio will likely help in your favor. But you'd have to defend those cases individually in court to even begin to make a fair-use argument. And I dont see how you could ever win any blanket decision in your favor.

With a good DMCA takedown story and compliance, you could potentially claim the copyright is responsibility of your users. And maybe you'll be too small, and the content, in general you are making too inconsequential, or even helpful (marketing wise) for anyone to care. But this is definitely be a project I would get a proper legal analysis of and have clear procedures and plans in place for any issues that may show up.

Re: Show HN: YTPics – Download pictures from YouTube videos

#36

Post by metadat »

teitoklien wrote: post #34
Beijinger wrote: post #14

I have extracted frames with vlc before before. They always look like shit. Like with a lower resolution. Why? Like if you freeze a youtube video the pic looks clean.

During streaming, lower res image frames are sent, to avoid buffering as much as possible, depending on your internet speed the res increases or decreases When you stop the frame, the video can download the highest res version without any problem, so you get crystal clear glimpse when paused, but blurry images when film is rolling.

> When you stop the frame, the video can download the highest res version without any problem, so you get crystal clear glimpse when paused, but blurry images when film is rolling.

If this were the case, when the player is paused and the "higher resolution frame" downloaded, there would be a discernable delay due to network and download latency, which I'm 100% certain is not the case. Pause any YT video and it is instantaneous with no perceivable delay or jank.

Edit: @teitoklien thank you for the correction about Adaptive Bitrate Streaming, I've removed this part of my reply so as to not spread misinformation. Sorry for any confusion!

Re: Show HN: YTPics – Download pictures from YouTube videos

#38

Post by teitoklien »

metadat wrote: post #36
teitoklien wrote: post #34

Earlier quoted context omitted.

During streaming, lower res image frames are sent, to avoid buffering as much as possible, depending on your internet speed the res increases or decreases When you stop the frame, the video can download the highest res version without any problem, so you get crystal clear glimpse when paused, but blurry images when film is rolling.

> When you stop the frame, the video can download the highest res version without any problem, so you get crystal clear glimpse when paused, but blurry images when film is rolling. If this were the case, when the player is paused and the "higher resolution frame" downloaded, there would be a discernable delay due to network and download latency, which I'm 100% certain is not the case. Pause any YT video and it is ins…

Um, no. You are wrong

Look into Adaptive Bitrate Streaming [0]. From what I’ve read HLS does work this way, when combined with Adaptive Bitrate streaming, the segment files are swapped midway depending on user device and connection quality (with each video segment being kept encoded at various qualities to change between as connection quality varies)

The screenshot thing is a fair question tho, why pausing leads to higher res. I think some players, do it custom, for User Experience, so that they can produce clean screenshots on pausing. I’ve seen YouTube do it for sure.

But for you’re main point, you’re objectively wrong, adaptive bit rates and swappable segment files are a thing.

Edit: (Don’t worry about it, being wrong is good hehe, i was wrong 7 times today while doing my work, helped me learn new things 3 out of those times, you helped me question myself and look back at my knowledge too, it’s been dusty for a while. Have a great day!)

[0] https://en.m.wikipedia.org/wiki/Adaptive_bitrate_streaming

Re: Show HN: YTPics – Download pictures from YouTube videos

#39

Post by edotrajan »

web0_cc wrote: post #19
KeplerBoy wrote: post #15

Earlier quoted context omitted.

This would be a good place to share that one line.

yt-dlp ${youtube_video_url} --get-url ffmpeg -ss ${seconds} -i "${first_url_from_yt-dlp}" -t 1 -r 4/1 -q:v 2 -vf scale="0:-1" ${target} -r 4/1: 4 frames per second Again this app is for mobile devices which lack yt-dlp+ffmpeg

Is it possible to get one screenshot from different periods of the same video like 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% with just one command.

If yes, could you please share for me here, it'd be really helpful, thanks

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