How To Inspect My Files To Know What Is Happening?

[abrogard]

I download from YT and typically get a number of files. Probably an mp4, a webm and a mkv.

And I get weirdly named files like name.f244.webm or name.webm.f137 or name.webm.mkv or name.mp4.f251 - like that.

Often only one of these will have sound - usually the mkv - when I play them in VLC.

Or even when played in anything else. Though I don't check much. I want things working in VLC.

I've been trying to find some way to 'rescue' the sound in the mp4 files, assuming it is there.

It was suggested to me that simply recoding them would fix it.

And I've been trying to find a way to play the mkv's and mp4's, with or without sound, on our t.v. which will only accept .avi Well, sometimes. There are some mp4 it will play but others it claims are unrecognised media or unsupported or something - that's part of my ignorance, I think I need to know how to discover which 'kind' of mp4 it doesn't like.

So I've tried Handbrake and Freemake Video Converter and most recently Xmedia Recode. Hoping to do both things.

Well xmedia has created a playable avi alright though it seems to have destroyed the resolution somewhat - but it hasn't fixed the audio thing.

So I realise I'm working in the dark. Just blundering around.

I need a bit of a crash course in video file analysis for the purpose of ascertaining what codecs have been used and what procedures now can be/should be used to get certain results. Perhaps. At a guess.

Some way to look at the files I've got, what they're made of and what I could/should do with them.

Would that be possible? Can anyone help me with that ? Is that a reasonable goal?

p.s. Yes, I know I can see details of a file in xmedia (just found it out actually) but the point is that currently that info presented is fairly meaningless to me. All I notice is the info on this last file doesn't seem to mention audio at all. So does that mean it simply has none? Was recorded without any?

[davexnet]

Use mediainfo in text view

[jagabo]

Many of the files are only audio or only video. A random youtube video for example:

>youtube-dl -F https://www.youtube.com/watch?v=4c4ui_TlGws

[youtube] 4c4ui_TlGws: Downloading webpage
[youtube] 4c4ui_TlGws: Downloading video info webpage
[info] Available formats for 4c4ui_TlGws:
format code  extension  resolution note
249          webm       audio only DASH audio   51k , opus @ 50k, 5.13MiB
250          webm       audio only DASH audio   64k , opus @ 70k, 6.40MiB
171          webm       audio only DASH audio  100k , vorbis@128k, 10.39MiB
251          webm       audio only DASH audio  116k , opus @160k, 11.64MiB
140          m4a        audio only DASH audio  131k , m4a_dash container, mp4a.40.2@128k, 14.25MiB
160          mp4        256x144    144p   57k , avc1.4d400c, 25fps, video only, 4.01MiB
133          mp4        426x240    240p  100k , avc1.4d4015, 25fps, video only, 7.07MiB
278          webm       256x144    144p  105k , webm container, vp9, 25fps, video only, 9.78MiB
242          webm       426x240    240p  163k , vp9, 25fps, video only, 10.54MiB
134          mp4        640x360    360p  177k , avc1.4d401e, 25fps, video only, 13.39MiB
243          webm       640x360    360p  280k , vp9, 25fps, video only, 16.39MiB
135          mp4        854x480    480p  283k , avc1.4d401e, 25fps, video only, 21.63MiB
244          webm       854x480    480p  445k , vp9, 25fps, video only, 23.40MiB
136          mp4        1280x720   720p  481k , avc1.4d401f, 25fps, video only, 34.86MiB
247          webm       1280x720   720p  789k , vp9, 25fps, video only, 37.84MiB
137          mp4        1920x1080  1080p  881k , avc1.640028, 25fps, video only, 61.92MiB
248          webm       1920x1080  1080p 1318k , vp9, 25fps, video only, 61.02MiB
17           3gp        176x144    small , mp4v.20.3, mp4a.40.2@ 24k, 8.83MiB
36           3gp        320x180    small , mp4v.20.3, mp4a.40.2, 24.70MiB
18           mp4        640x360    medium , avc1.42001E, mp4a.40.2@ 96k, 39.64MiB
43           webm       640x360    medium , vp8.0, vorbis@128k, 55.86MiB
22           mp4        1280x720   hd720 , avc1.64001F, mp4a.40.2@192k (best)

[abrogard]

that's very interesting. how did you get that download?
can i get that?
and what's the point of so many files?
if I upload to youtube will it somehow create all those files from my simple upload?
and how do downloading progs know which files to get?
do they have to get one of each (vid and audio) and combine them?

[jagabo]

that's very interesting. how did you get that download?

I used a command line program called youtube-dl.

can i get that?

Yes. You can see the command line I used on the first line.

and what's the point of so many files?

Different files are streamed to different devices. Different resolutions, bitrates, codecs, etc. Players may switch between different bitrate vides as available bandwidth changes.

if I upload to youtube will it somehow create all those files from my simple upload?

Yes.

and how do downloading progs know which files to get?

They pick the ones they want.

do they have to get one of each (vid and audio) and combine them?

Yes.

[abrogard]

thanks for that.

very interesting.

and that doesn't cover all of them either does it? all those subtitle files....

[sneaker]

https://github.com/rg3/youtube-dl/blob/master/README.md#subtitle-options

[abrogard]

A very good link. Thanks for that.

Seems perhaps I've made a mountain out of a molehill. Thought I needed to understand much about the internal composition of these video files and the codecs used to produce them in order to know how to massage them into a form that, for instance, my t.v. would play properly.

But it turns out that most of these files simply have no audio is the main problem. And others are unsupported types.

And I just need any simple tool to look at them and see if they've got audio or not and I could I suppose add audio in if there's no other option but first I should just make sure there's not a 'good' file in the download somewhere.

I don't really need to know any more than that, do I? Might like to. But don't need.

[jagabo]

Given the names of your files (name.f244.webm, name.webm.f137) I suspect you can use the names as a guide. Note the corresponding numbers in the youtube-dl list I posted:

244          webm       854x480    480p  445k , vp9, 25fps, video only, 23.40MiB
137          mp4        1920x1080  1080p  881k , avc1.640028, 25fps, video only, 61.92MiB

I believe the numbers and properties are consistent across all youtube videos.

[abrogard]

That's a very good clue, thanks.

[sneaker]

And I just need any simple tool to look at them and see if they've got audio or not and I could I suppose add audio in if there's no other option but first I should just make sure there's not a 'good' file in the download somewhere.

Youtube-dl allows you set an automatic format selection. For example you can set it to download 1080p AVC with AAC audio, only (or lower if the video doesn't have higher resolution) for compatibility with your TV. If you put ffmpeg.exe into the youtube-dl folder it will automatically combine video and audio into a single file.

https://github.com/rg3/youtube-dl/blob/master/README.md#format-selection (see examples)
https://github.com/rg3/youtube-dl/blob/master/README.md#on-windows-how-should-i-set-up...-the-exe-files

The documentation really covers everything.

[abrogard]

Yes, okay. I'll get into yt-dl command line. I have yt-dl. I have been using it. But via yt-dl dropper. I guess I need to configure the defaults it uses. ffmpeg is in the folder but it still produces separate audio and video files.