The basics of FFMPEG | DenshiHelp

[00:00] hello i'm denchi and in today's video

[00:02] i'm going to be showing you how to use

[00:04] ffmpeg with some basic examples so i'll

[00:06] just get rid of a bunch of files here

[00:08] real quick

[00:09] and just pretend i only have one file

[00:11] here outro.mp4 now if i double click on

[00:14] this and i play it back

[00:16] [Music]

[00:18] you'll notice just the outro from all my

[00:20] videos and

[00:21] yeah that's what i use is my outro let's

[00:23] say i want to convert it

[00:24] to an mkv for example well i have a

[00:27] program named

[00:28] ffmpeg and if you're running linux and

[00:30] you have a desktop environment installed

[00:32] this is already on your system including

[00:34] all the codecs that are going to need to

[00:36] do all the conversions

[00:38] so let's say i want to convert this file

[00:39] so i'm going to do ffmpeg-i

[00:42] outro so i means input and if i don't

[00:45] give it any

[00:45] any other parameters and just press

[00:47] enter it will give me information on the

[00:50] file

[00:50] so as you can see here it tells me that

[00:52] um stream00

[00:54] it's using the hevc encoder which is a

[00:57] modern functional

[00:58] encoder you 420p like pixel format

[01:01] it's at 1920 by 1080 in terms of

[01:03] resolution it's at 60fps

[01:05] and all of the stuff for audio it's

[01:06] using aac it's a 48

[01:09] 000 hertz sample rate stereo and 128

[01:13] kilobytes per second as the bit rate um

[01:15] so yeah all of that stuff

[01:17] now let's say i want to convert it to an

[01:18] mkv without

[01:20] any parameters fmpeg defaults to a bunch

[01:22] of stuff that it has pre-built in it

[01:24] i can just tell it to convert it to

[01:26] outro dot mk so it might take a little

[01:28] bit of time because this is

[01:30] a 20 second long video but eventually

[01:32] after i've done running this command so

[01:34] outro that mp4

[01:35] auto mkv just specifying i want it to go

[01:38] from this is my input to just this

[01:40] output

[01:40] i get an output and if i double click

[01:42] and play this

[01:45] you'll see it's it's pretty much the

[01:46] same thing now what if i want to specify

[01:48] a different encoder so

[01:50] this used h264 as the encoder because by

[01:53] default

[01:54] ffmpeg will try to use h64 when

[01:56] converting things to mkv

[01:58] let's say i want to use um h265 or hevc

[02:03] i can do dash c v

[02:07] and specify lib x265

[02:10] as my video codec same for audio if i

[02:13] want to use aac for example which is

[02:15] higher quality

[02:15] lossless audio i can do dash c colon a

[02:20] aac i can give them more options

[02:23] so for example i want to scale the video

[02:25] i can do dash

[02:26] s and like 1280 x 720

[02:30] that's 720p let's say i want to give it

[02:33] a rate i'll i'll keep this for now

[02:35] in the meantime before i talk about more

[02:37] options i'm going to quickly um

[02:40] run this and cancel it so i have it

[02:41] saved i'm going to talk about how to

[02:44] actually get the encoder list so

[02:46] you saw me write out lib x265 how do i

[02:48] know what all the encoders are well if

[02:50] you want to see all the encoders

[02:51] you do ffmpeg dash encoders

[02:54] and that will print them all out if i

[02:56] want all of those to go to like a file

[02:58] just do ffmpeg

[03:00] encoders and send them over to like i

[03:02] don't know

[03:02] [Music]

[03:04] encoders.txt so there you go

[03:06] and it will create encoders.txt you can

[03:08] look through these uh

[03:09] and there's all the encoders you can

[03:11] possibly use on a system

[03:12] now not all of these might work with

[03:14] your system maybe you don't have the

[03:15] hardware for some of the some of these

[03:17] or your processors too old or

[03:19] or maybe they're just not supporting

[03:20] enough that certain things downloaded or

[03:22] something like that

[03:22] but most of these should work and the

[03:25] reason all of these are here is because

[03:26] video comes in many variations so the

[03:28] one i use

[03:29] was let's see if i can spot it here we

[03:31] are uh lib

[03:33] x265 so this is s265 also known as hevc

[03:38] uh h264 this is the nvidia version but

[03:41] up here

[03:41] we got h64va api so that's the version

[03:44] for um video accelerated stuff

[03:47] um and then somewhere up there here we

[03:50] are you'll find

[03:50] libx 264 so that's h64 so that's the

[03:53] actual you know

[03:54] standard codec anyway but this isn't

[03:57] what's important now let's go back to

[03:58] where we were uh before i think i need

[04:00] to go

[04:00] uh wait a second you know open up the

[04:03] main toolbar

[04:04] and not maintain sorry uh settings uh

[04:07] show tabs go back to the previous file i

[04:09] was in

[04:10] this one anyway so back to what i was

[04:12] talking about before

[04:13] let's say i want to take i don't know

[04:16] let's just delete this file let's say i

[04:17] want to take

[04:18] outro that mp4 and convert it uh with

[04:21] what i was doing before

[04:23] uh this um i want to use aac as my audio

[04:26] codec

[04:27] x265 as my video codec basically the

[04:29] best ones out there pretty much

[04:31] and i want the resolution to be 720p

[04:34] let's say i want to

[04:35] change the audio rate so rate colon

[04:38] a and i give it something like 44

[04:42] 100 a common audio rate uh just

[04:45] give it a couple spaces so things are a

[04:46] little bit more evenly formatted here

[04:48] um spaces don't matter let's say i want

[04:50] to change the

[04:51] video bit rate dash b the one megabyte

[04:55] at most it can reach one megabyte per

[04:57] second

[04:57] most likely won't but if i really want

[04:59] to uh or let's say i want the audio

[05:01] bitrate to be something i can do

[05:03] dash b a and bitrate audio and set it to

[05:05] 192 kilo

[05:06] kilobytes per second or kilohertz no not

[05:09] killer it's kilobytes per second

[05:11] um now setting video like uh bitrates is

[05:14] pretty pointless when you're using

[05:15] something like x365 or h264 all that

[05:17] stuff because there's already an inbuilt

[05:19] utility for it it's called

[05:20] crf and it's much better it's uh very

[05:23] varying the bit rate

[05:24] uh based off a number you give it so the

[05:26] lower the number is

[05:27] the better the quality will be but the

[05:28] bigger the following follows

[05:30] so let's say i want it to be 24. 24 is a

[05:34] good number uh i

[05:35] most of my videos are you know 20 i set

[05:37] the crf rate to 24 when i compress them

[05:39] including this one it's 24. and um

[05:43] you know as you can see it looks pretty

[05:44] good if you need higher quality

[05:46] 20 but like it's pretty

[05:48] indistinguishable like a little bit

[05:49] maybe with more noisy video but you know

[05:52] for most video it's perfectly fine

[05:53] anyway moving on let's say i want to

[05:56] change the duration as well this video

[05:58] i can do dash ss to declare what i

[06:00] wanted to start i wanted to start at

[06:01] well zero hours zero minutes zero

[06:04] seconds

[06:05] and zero milliseconds and let's say i

[06:07] want it to end so dash

[06:08] t at zero hours zero minutes

[06:12] and zero five seconds and zero

[06:14] milliseconds

[06:15] i can also that's pretty much it no so

[06:18] i'm going to do after outside mp4 i'm

[06:19] going to use x265 i'm going to set my

[06:21] codec to aac for audio

[06:24] i'm going to scale it down to 720p

[06:26] change the audio bitrate to

[06:27] 44 100. i use crf 24 so you know pretty

[06:31] good quality for

[06:32] h.265 and stuff set my bitrate of audio

[06:35] to 192 kilobytes per second

[06:37] uh start the video at zero zero just the

[06:40] beginning of the video

[06:41] and end it at five seconds so let's

[06:42] press enter and let it work

[06:49] since it only had to do five seconds it

[06:50] was relatively quick and if we play this

[06:52] back

[06:56] as you can see it lasts five seconds

[06:58] it's in 720p and

[06:59] everything has been applied so ffmpeg is

[07:02] a really powerful tool when you want to

[07:03] mask convert files because you could

[07:04] just write a script and and mass convert

[07:06] every single mp4 file to

[07:08] a different format or every single mp4

[07:10] file compress it to something else or or

[07:12] something like that

[07:13] and let's say i want to take this

[07:15] outro.mp4 file

[07:16] and turn it into audio well that's the

[07:18] same concept dash i

[07:20] altered it before if i want to specify a

[07:22] specific audio codec i guess i don't

[07:23] know

[07:23] lib opus or something but i'm just going

[07:26] to say outro dot wav

[07:28] let's just turn it into a waff instantly

[07:30] done there you go australia double click

[07:32] that

[07:34] and as you can see it plays back because

[07:36] i've converted it to audio

[07:37] and here right before i end this video

[07:39] because i've talked about all the main

[07:40] options

[07:40] let's do a fun little experiment let's

[07:42] transform this outdoor.web and this

[07:44] image into a video

[07:45] so i'm going to take out that wav and

[07:48] essentially mix it with this image so

[07:49] i'm going to do ffmpeg

[07:51] dash i outro

[07:54] and then dash i image.png and i'm going

[07:58] to specify

[08:00] a specific codec so let's say i want

[08:03] libx265 relatively good the crf

[08:06] i don't know 20

[08:10] 20 20 is pretty good in terms of quality

[08:12] images are a little bit messed up when

[08:13] it comes to this kind of stuff

[08:15] and let's say i want um something like

[08:18] uh

[08:19] audio codecs okay i might want to

[08:21] specify a bitrate for audio though so

[08:23] i'm going to do b

[08:24] a and set it to 192 kilohertz so let's

[08:27] press enter on this

[08:29] and oh yeah i forgot to set an output

[08:31] file so wait a second i'm going to

[08:33] specify i want it to be

[08:34] outro image dot mp4 press

[08:37] enter and just let it convert there you

[08:38] go it's already done double click on

[08:40] this

[08:41] and as you can see it's the image with

[08:43] the audio it's just you know the image

[08:45] playing back in it and it has the audio

[08:47] from uh outro dot uh wove which is just

[08:50] you know just the raw

[08:51] 20 second audio and it mixes it with

[08:54] this image so if you've ever wanted to

[08:55] just have a still image

[08:56] and you're talking you can make that

[08:58] pretty easily in the file itself is

[09:00] negligible in terms of sizes it's

[09:01] minuscule it's 489 kilobytes so if you

[09:05] ever need to make a video where it's

[09:06] just like

[09:06] an image and that's all you can do that

[09:08] pretty easily with this

[09:10] so anyway thanks for watching my video

[09:11] on how to use you know ffmpeg with some

[09:13] basic options

[09:14] i'll have all a bunch of examples in the

[09:16] description if you want to take a look

[09:17] at them i'll just have this entire thing

[09:19] in the description actually

[09:20] um and yeah ffmpeg is a really useful

[09:23] tool i recommend if you're into video

[09:24] stuff

[09:25] you learn how to use it uh the best

[09:27] encoders for video

[09:28] are at the moment lib x265

[09:32] best encoder for audio is aac because

[09:34] high quality

[09:35] x265 is you know as long as you set your

[09:37] crf rate appropriately it's going to be

[09:39] perfectly fine in terms of quality

[09:40] might be a little slow because

[09:42] processors and stuff um if you need to

[09:44] deal with

[09:45] something like nvidia and coding you can

[09:47] do obviously what was it called um

[09:50] nvenk uh underscore hevc that's another

[09:54] codec you can use but it's it's or

[09:56] actually i think it's hebc underscore

[09:58] and bank

[09:59] and it's it's fast but it isn't as

[10:02] precise because

[10:03] gpus aren't like perfect like processors

[10:05] when it comes to video and

[10:06] the file sizes will be larger and it

[10:08] won't be as you know good

[10:09] it won't be as high quality video but

[10:11] yeah that's pretty much it

[10:13] thanks for watching my video goodbye

[10:25] [Music]

[10:35] you