Turn: FFmpeg basic usage

Ffmpeg

FFmpeg Basic Usage

The problem to be solved in this lesson

What is the transcoding process for 1.FFmpeg?

2. What do the common video formats contain?

3. How do I extract this content from a video file?

4. How do I convert from one format to another format?

5. How do I zoom in and out of a video?

6. How to rotate, flip, fill, crop, blur, sharpen video?

7. How to add logo to video, delete logo?

8. How to add text to the video, dynamic text?

9. How do I process pictures?

10. How to record, add dynamic logo, mosaic video?

The first part

Basis

Terms

Container (Container)

A container is a file format, such as Flv,mkv. Contains the following 5 streams and file header information.

Flow (Stream)

is a video data transmission mode, 5 kinds of streams: audio, video, subtitles, attachments, data.

Frames (frame)

The frame represents a still image, divided into I-frames, p-frames, B-frames.

Codec (CODEC)

is to compress or decompress the video, CODEC =code (encoded) +decode (decoding)

For reuse/demultiplexer (MUX/DEMUX)

Put different streams in the container in accordance with the rules of a container, which is called multiplexing (MUX)

To parse a different stream from a container, which is called a reusability (Demux).

Brief introduction

The name of FFmpeg comes from the MPEG video coding standard, the front "FF" stands for "Fast Forward", and FFmpeg is an open-source computer program that can be used to record, convert digital audio, video, and turn it into a stream. It is easy to convert multiple video formats to each other.

FFmpeg users have Google,facebook,youtube, Youku, iqiyi art, potatoes and so on.

Composition

1, Libavformat: For a variety of audio and video packaging format generation and resolution, including to obtain the information needed to decode the decoding context structure and read the audio and video frames and other functions, containing demuxers and Muxer library;

2, Libavcodec: For various types of sound/image codec;

3, Libavutil: Contains some common tool functions;

4, Libswscale: For video scene scaling, color mapping conversion;

5, Libpostproc: For the post-processing effect;

6, FFmpeg: is a command line tool for the video file conversion format, also supports real-time encoding of the TV card;

7, Ffsever: is an HTTP multimedia real-time broadcast streaming server, support time translation;

8, Ffplay: is a simple player, using the FFmpeg library parsing and decoding, through the SDL display;

FFmpeg processing Process

Filters (Filter)

In multimedia processing, filter means a software tool that is used to modify the contents of an input file before it is encoded into an output file. such as: Video flip, rotate, zoom and so on.

Syntax: [Input_link_label1][input_link_label2] ... filter_name=parameters [Output_link_label1][output_link_label2] ...

Filter Diagram Link Label: Is the name of the input or output of the tag filter

1. Video Filter-VF

If the TESTSRC video rotates 90 degrees in a clockwise direction

Ffplay-f lavfi-i TESTSRC-VF transpose=1

such as TESTSRC video horizontal flip (flip left and right)

Ffplay-f lavfi-i TESTSRC-VF Hflip

2. Audio Filter-AF

For slow playback, the sound speed is 50% of the original speed

Ffplay P629100.mp3-af atempo=0.5

How do I rotate 90 degrees clockwise and flip horizontally?

Filter Chain (Filterchain)

Basic syntax

Filterchain = A comma-delimited set of filter

Syntax: "Filter1,filter2,filter3,... Filtern-2,filtern-1,filtern"

Rotate 90 degrees clockwise and flip horizontally

Ffplay-f lavfi-i TESTSRC-VF Transpose=1,hflip

How do I compare a horizontal flip video to a source video? See how the filter chain is implemented.

Filter Chain (Filterchain)

The first step: The source video width is enlarged twice times.

Ffmpeg-i jidu.mp4-t 10-VF Pad=2*iw output.mp4

Step Two: Flip the source video horizontally

Ffmpeg-i jidu.mp4-t 10-VF Hflip output2.mp4

Step three: Horizontal Flip Video Overlay Output.mp4

Ffmpeg-i output.mp4-i Output2.mp4-filter_complex overlay=w compare.mp4

Isn't it complicated?

A filter diagram (filtergraph) with a link tag requires only one command.

Filter Diagram (filtergraph)

Basic syntax

Filtergraph = A semicolon-delimited set of Filterchain

"Filterchain1;filterchain2;...filterchainn-1;filterchainn"

Categories of Filtergraph

1. Simple and one-to-one

2, complex (complex) many-to-one, many-to-many

Filter Diagram (filtergraph)

Simple filter Diagram processing flow:

Complex filter diagram processing flow:

A complex filter diagram can be found to be 2 steps less efficient than a simple filter diagram, and FFmpeg recommends using a complex filter diagram as much as possible.

Answer the above questions to achieve horizontal flip video and source video to compare

Filter Diagram (filtergraph)

View results directly with Ffplay:

Ffplay-f lavfi-i TESTSRC-VF Split[a][b]; [A]pad=2*iw[1]; [B]hflip[2]; [1] [2]overlay=w

F1:split filter creates a copy of two input files and marks them as [a],[b]

F2: [A] as input to the pad filter, the pad filter produces twice times the width and outputs to [1].

F3: [b] as input to the Hflip filter, the Vflip filter flips the video horizontally and outputs to [2].

F4: Use the overlay filter to cover [2] next to [1].

Select Media Stream

Some multimedia containers, such as avi,mkv,mp4, can contain multiple streams of different kinds, and how to extract various streams from the container.

Grammar:

-map File_number:stream_type[:stream_number]

Here are some descriptions of the special flow symbols:

1,-map 0 Select all the streams for the first file

2,-map i:v get all the video stream from the file ordinal I (index),-map i:a get all the audio stream,-map i:s get all the caption stream and so on.

3, the special parameter-an,-vn,-sn excludes all audio, video, subtitle stream respectively.

Note: The file sequence number and the stream ordinal count from 0 onwards.

Select Media Stream

Part II

View Help

Help

The FFmpeg tool has a huge console help. The following table describes some of the options that are available, in italics, for the items to be replaced, and Ffplay and ffprobe have similar options.

Help

Available bit streams: FFMPEG–BSFS

Codecs available: Ffmpeg–codecs

Available decoders: Ffmpeg–decoders

Available encoders: ffmpeg–encoders

Available Filters: Ffmpeg–filters

Available Video formats: Ffmpeg–formats

Available channel layouts: ffmpeg–layouts

Available License:ffmpeg–l

Available pixel formats: FFMPEG–PIX_FMTS

Available protocols: Ffmpeg-protocals

Part III

Bitrate, frame rate, and file size

Overview

Bitrate and frame rate are the most important basic features of video files, and their unique settings determine video quality. If we know the bitrate and the length of time then it is easy to calculate the size of the output file.

Frame rate: Frame rate is also called frame frequency, frame rate is the number of frames per second in the video file, the naked eye want to see a continuous moving image needs at least 15 frames.

Bitrate: Bit rate (also called code rate, data rate) is a parameter that determines the overall video/audio quality, the number of bytes processed in seconds, the bitrate is proportional to the video quality, and the bit rate in the video file is expressed in bps.

Frame rate

1. Set the frame rate with the-R parameter

Ffmpeg–i input–r fps output

2. Set frame rate with FPS filter

Ffmpeg-i CLIP.MPG-VF fps=fps=25 CLIP.WEBM

Predefined values for frame rate:

For example, the set code rate is 29.97fps, the following three ways have the same result:

Ffmpeg-i input.avi-r 29.97 Output.mpg

Ffmpeg-i input.avi-r 30000/1001 Output.mpg

Ffmpeg-i input.avi-r NETSC Output.mpg

Code rate, File size

Setting the bitrate –b parameter

-B

Ffmpeg-i film.avi-b 1.5M Film.mp4

Audio:-b:a Video:-B:v

Set video bitrate to 1500kbps

Ffmpeg-i input.avi-b:v 1500k Output.mp4

Control output File Size

-FS (file size initials)

Ffmpeg-i Input.avi-fs 1024K Output.mp4

Calculate output File Size

(Video bitrate + audio bitrate) * Duration/8 = file size K

Fourth part

Adjust video resolution

Adjust video resolution

1, set the video resolution with the-s parameter, the parameter value wxh,w width unit is pixel, h height unit is pixel

Ffmpeg-i input_file-s output_file

2, pre-defined video size

The following two commands have the same effect

Ffmpeg-i input.avi-s 640x480 Output.avi

Ffmpeg-i input.avi-s VGA Output.avi

The following table lists all the predefined dimensions

Scale Filter Adjust resolution

The advantage of scale filter is that you can use some additional parameters

Grammar:

SCALE=WIDTH:HEIGHT[:INTERL={1|-1}]

The following table lists the common additional parameters

Example

The following two commands have the same effect

Ffmpeg-i input.mpg-s Output.mp4

Ffmpeg-i INPUT.MPG-VF scale=320:240 Output.mp4

Scale the input video proportionally

Change to source video half size

Ffmpeg-i INPUT.MPG-VF SCALE=IW/2:IH/2 Output.mp4

Change the size of the original video to 90%:

Ffmpeg-i INPUT.MPG-VF scale=iw*0.9:ih*0.9 Output.mp4

Example

At the resolution of unknown video, the resolution of the adjustment is guaranteed to have the same cross-aspect ratio as the source video.

Width fixed 400, height proportional:

Ffmpeg-i INPUT.AVI-VF scale=400:400/a

Ffmpeg-i INPUT.AVI-VF scale=400:-1

In contrast, the height is fixed at 300 and the width is proportional:

Ffmpeg-i INPUT.AVI-VF scale=-1:300

Ffmpeg-i INPUT.AVI-VF scale=300*a:300

Fifth part

Crop/Fill Video

Cropping Video crop filter

Select the rectangular area you want from the input file to the output file, commonly used to go to the black edge of the video.

Grammar: Crop:ow[:oh[:x[:y:[:keep_aspect]]

Example

Clip the input video to the left One-third, Middle One-third, and one of the right three points:

Ffmpeg-i INPUT-VF crop=iw/3:ih:0:0 Output

Ffmpeg-i INPUT-VF crop=iw/3:ih:iw/3:0 Output

Ffmpeg-i INPUT-VF crop=iw/3:ih:iw/3*2:0 Output

Crop the center of a frame

When we want to crop the area in the middle of the frame, the crop filter can skip the input x and Y values, and their default values are

Xdefault = (input width-output width)/2

Ydefault = (input height-output height)/2

Ffmpeg-i input_file-v crop=w:h output_file

Crop half the middle area:

Ffmpeg-i INPUT.AVI-VF CROP=IW/2:IH/2 Output.avi

Example

Compare cropped video and source video comparison

Ffplay-i JIDU.MP4-VF Split[a][b]; [A]drawbox=x= (IW-300)/2: (ih-300)/2:w=300:h=300:c=yellow[a]; [A]pad=2*iw[c]; [b]crop=300:300: (iw-300)/2: (ih-300)/2[b]; C [b]overlay=w*2.4:40

Automatically detect cropping areas

Cropdetect Filter Auto Detect black Edge area

Ffplay JIDU.MP4-VF Cropdetect

Then use the detected values to crop the video

Ffplay JIDU.MP4–VF crop=672:272:0:54

Fill Video (PAD)

Adds a quick extra area to the video frame, often showing different aspect ratios when playing

Grammar: Pad=width[:height:[:x[:y:[:color]]

Example

Create a 30-pixel pink width to surround a SVGA-sized picture:

Ffmpeg-i PHOTO.JPG-VF Pad=860:660:30:30:pink framed_photo.jpg

?

Similarly, you can make testsrc video with 30 pixels of pink surround video

Ffplay-f lavfi-i TESTSRC-VF Pad=iw+60:ih+60:30:30:pink

4:3 to 16:9

Some devices can only play 16:9 of the cross-aspect ratio, 4:3 of the cross-aspect ratio must be in the horizontal direction of the two sides filled with 16:9,

Height is maintained, width equals height multiplied by 16/9,x (input file horizontal displacement) The value is computed by the expression (output_width-input_width)/secondly.

The general commands from 4:3 to 16:9 are:

Ffmpeg-i INPUT-VF Pad=ih*16/9:ih:(ow-iw)/2:0:color output

Example

Ffplay-f lavfi-i testsrc-vf pad=ih*16/9:ih: (OW-IW)/2:0:pink

16:9 to 4:3

In order to display a 16:9 aspect ratio with a 4:3 aspect ratio, fill the vertical sides of the input file, the width remains constant, and the height is the width of the 3/4,y value (the vertical offset of the input file) is calculated by an expression (Output_height-input_height)/2.

Common commands from 16:9 to 4:3:

Ffmpeg-i input-vf pad=iw:iw*3/4:0: (oh-ih)/2:color output

Example

Ffplay-f lavfi-i testsrc=size=320x180-vf pad=iw:iw*3/4:0: (OH-IH)/2:pink

Sixth part

Flip and rotate

Flip

Horizontal Flip Syntax:-VF hflip

Ffplay-f lavfi-i TESTSRC-VF Hflip

Vertical Flip Syntax:-VF vflip

Ffplay-f lavfi-i TESTSRC-VF Vflip

Rotating

Syntax: transpose={0,1,2,3}

0: Rotate 90° counterclockwise and flip vertically

1: Clockwise rotation 90°

2: Rotate counterclockwise 90°

3: Rotate 90° clockwise and flip horizontally

Seventh part

Blur, sharpen

Fuzzy

Syntax: Boxblur=luma_r:luma_p[:chroma_r:chram_p[:alpha_r:alpha_p]]

Ffplay-f lavfi-i TESTSRC-VF Boxblur=1:10:4:10

Note: The range of Luma_r and alpha_r radius is 0~min (w,h)/2, Chroma_r radius is 0~min (cw/ch)/2

Sharpening

Syntax:-VF unsharp=l_msize_x:l_msize_y:l_amount:c_msize_x:c_msize_y:c_amount

All parameters are optional and the default value is 5:5:1.0:5:5:0.0

L_msize_x: Horizontal luminance matrix, value range 3-13, default value is 5

L_msize_y: Vertical luminance matrix, value range 3-13, default value is 5

L_amount: Brightness intensity, value range -2.0-5.0, negative number is blur effect, default value 1.0

c_msize_x: Horizontal color matrix, value range 3-13, default value 5

C_msize_y: Vertical color matrix, value range 3-13, default value 5

C_amount: Color intensity, value range -2.0-5.0, negative number is blur effect, default value 0.0

Example

Using default values, the luminance matrix is 5x5 and the luminance value is 1.0

Ffmpeg-i INPUT-VF Unsharp Output.mp4

Gaussian blur effect (stronger than the blur):

Ffplay-f lavfi-i TESTSRC-VF unsharp=13:13:-2

Eighth part

Overlay (PIP)

Covered

Syntax: Overlay[=x[:y]

All parameters are optional and the default value is 0

Example

Logo in the top left corner

Ffmpeg-i pair.mp4-i Logo.png-filter_complex Overlay Pair1.mp4

Example

upper right Corner:

Ffmpeg-i pair.mp4-i Logo.png-filter_complex overlay=w-w pair2.mp4

Lower left corner:

Ffmpeg-i pair.mp4-i Logo.png-filter_complex overlay=0:h-h pair2.mp4

Lower right corner:

Ffmpeg-i pair.mp4-i Logo.png-filter_complex overlay=w-w:h-h pair2.mp4

Remove logo

Syntax:-VF Delogo=x:y:w:h[:t[:show]]

X:y the coordinates from the upper left corner

W:h logo width and height

T: Thickness of Rectangle Edge default value 4

Show: If set to 1 has a green rectangle, the default value is 0.

Ffplay-i JIDU.MP4-VF delogo=50:51:60:60:100:0

Nineth part

Add text

Add text

Grammar:

drawtext=fontfile=font_f:text=text1[:p 3=v3[:p 4=v4[...]]

Common parameter values

X: The horizontal axis from the upper left corner

Y: Ordinate from upper left corner

FontColor: Font Color

FontSize: Font Size

Text: Textual content

Textfile: Text File

T: Timestamp, per second

N: Frame number start position is 0

Draw/enable: Control file display, if the value is 0 not shown, 1 display, you can use the function

Simple usage

1. Add welcome text in top left corner

Ffplay-f lavfi-i COLOR=C=WHITE-VF drawtext=fontfile=arial.ttf:text=welcom

2. Add good day in the center

Ffplay-f lavfi-i color=c=white-vf drawtext= "fontfile=arial.ttf:text= ' GoodDay ': x= (W-TW)/2:y= (h-th)/2"

3. Set the font color and size

Ffplay-f lavfi-i color=c=white-vf drawtext= "fontfile=arial.ttf:text= ' Happy Holidays ': x= (W-TW)/2:y= (h-th)/2: Fontcolor=green:fontsize=30 "

Dynamic text

Implementing dynamic text with T (time-second) variables

1. Top horizontal scrolling

Ffplay-i jidu.mp4-vf drawtext= "fontfile=arial.ttf:text= ' Dynamic RTL text ': x=w-t*50:fontcolor=darkorange:fontsize= 30 "

2. Horizontal scrolling at the bottom

Ffplay-i jidu.mp4-vf drawtext= "Fontfile=arial.ttf:textfile=textfile.txt:x=w-t*50:y=h-th:fontcolor=darkorange: Fontsize=30 "

3. Scroll vertically from bottom to top

Ffplay jidu.mp4-vf drawtext= "textfile=textfile:fontfile=arial.ttf:x= (W-TW)/2:y=h-t*100:fontcolor=white:fontsize= 30 "

Want to implement the current time in the upper right corner?

Dynamic text

Display the current time in the upper-right corner localtime

Ffplay jidu.mp4-vf drawtext= "fontfile=arial.ttf:x=w-tw:fontcolor=white:fontsize=30:text= '%{localtime\:%H\\\:%M\\ \:%s} ' "

Displays the current time every 3 seconds

Ffplay jidu.mp4-vf drawtext= "fontfile=arial.ttf:x=w-tw:fontcolor=white:fontsize=30:text= '%{localtime\:%H\\\:%M\\ \:%s} ': Enable=lt (mod (t\,3) \,1) "

Tenth part

Image processing

Image support

FFmpeg supports most image processing, except for ljpeg (lossless JPEG), which can be decoded except exr,pic,ptx, all of which can be encoded.

Capture a picture using the –SS (seek from start) parameter.

Ffmpeg-ss 01:23:45-i Jidu.mp4 image.jpg

Create a GIF image from your video

Ffmpeg-i jidu.mp4-t 10-pix_fmt rgb24 jidu.gif

Convert video to picture (one picture per frame)

Ffmpeg-i Clip.avi frame%4d.jpg

Convert Pictures to Videos

Ffmpeg-f image2-i img%4d.jpg-r Video.mp4

Crop, fill

As with videos, images can be cropped and filled

Cutting

Ffmpeg-f lavfi-i RGBTESTSRC-VF crop=150:150 crop_rg.png

Fill

Ffmpeg-f lavfi-i SMPTEBARS-VF Pad=360:280:20:20:orange pad_smpte.jpg

Flip, rotate, overwrite

Same as the video picture can flip, rotate and overlay

Flip

Ffmpeg-i ORANGE.JPG-VF Hflip orange_hfilp.jpg

Ffmpeg-i ORANGE.JPG-VF Vflip orange_vfilp.jpg

Rotating

Ffmpeg-i IMAGE.PNG-VF transpose=1 Image_rotated.png

Covered

Ffmpeg-f lavfi-i rgbtestsrc-s 400x300 RGB. png

Ffmpeg-f lavfi-i Smptebars Smpte.png

Ffmpeg-i RGB. Png-i smpte.png-filter_complex overlay= (w-w)/2: (h-h)/2 rgb_smpte.png

11th part

Other advanced Techniques

Screen recording

Display device Name

Ffmpeg-list_devices 1-f dshow-i Dummy

Call camera

Ffplay-f dshow-i video= "Integrated Camera"

Save As File

Ffmpeg-y-F dshow-s 320x240-r 25-i video= "Integrated Camera"-b:v 800k-vcodec MPEG4 new.mp4

Add caption Subtitles

Grammar –VF Subtitles=file

Ffmpeg-i JIDU.MP4-VF subtitles=rgb.srt Output.mp4

Video tremor, color balance

Video tremor

Ffplay–i jidu.mp4-vf CROP=IN_W/2:IN_H/2: (in_w-out_w)/2+ ((In_w-out_w)/2) *sin (N/10):(In_h-out_h)/2 + ((in_h-out_h)/2 ) *sin (N/7)

Color balance

Ffplay-i JIDU.MP4-VF Curves=vintage

changing colors

Ffplay-i jidu.mp4-vf hue= "H=2*pi*t:s=sin (2*pi*t) +1"

Color conversion Black and white

Ffplay-i jidu.mp4-vf lutyuv= "u=128:v=128"

Set Audio video playback speed

3 times times video playback video

Ffplay-i JIDU.MP4-VF SETPTS=PTS/3

? Speed Play Video

Ffplay-i jidu.mp4-vf setpts=pts/(3/4)

Twice times the speed of playing audio

Ffplay-i Speech.mp3-af atempo=2

Problem: Video and audio simultaneously 3/4 slow playback

Cut a picture every second

Ffmpeg-i input.flv-f IMAGE2-VF Fps=fps=1 out%d.png

Cut a picture every 20 seconds

Ffmpeg-i input.flv-f IMAGE2-VF fps=fps=1/20 out%d.png

Note: The FFmpeg version n-57961-gec8e68c can be truncated at a maximum of 20s per image.

Multiple sheets merged into a single file (2x3)? Every 1000 frames (seconds =1000/fps25) is 40s truncated a graph

Ffmpeg? -I jidu.mp4-frames 3-vf "Select=not (mod (n\,1000)), scale=320:240,tile=2x3" Out.png

Mosaic Video

Mosaic Video

Create a mosaic video with multiple input files:

Ffmpeg-i jidu.mp4-i jidu.flv-i "Day by day Sbs.mp4"-i "Dangerous.mp4"-filter_complex "nullsrc=size=640x480 [base]; [0:v] setpts=pts-startpts, scale=320x240 [Upperleft]; [1:v] setpts=pts-startpts, scale=320x240 [upperright]; [2:v] setpts=pts-startpts, scale=320x240 [Lowerleft]; [3:v] setpts=pts-startpts, scale=320x240 [lowerright]; [Base] [Upperleft] overlay=shortest=1 [TMP1]; [TMP1] [Upperright] overlay=shortest=1:x=320 [TMP2]; [TMP2] [Lowerleft] overlay=shortest=1:y=240 [Tmp3]; [Tmp3] [Lowerright] overlay=shortest=1:x=320:y=240 "-c:v libx264 output.mkv

Dynamic logo Movement

The logo moves from left to right after 1 or 2 seconds:

Ffplay-i JIDU.MP4-VF Movie=logo.png[logo]; [In] [logo]overlay=x= ' If (GTE (t\,2) \, ((t-2) *80)-w\,nan) ': y=0

2, 2 seconds after the logo moved from left to right after the stop in the upper left corner

Ffplay-i JIDU.MP4-VF Movie=logo.png[logo]; [In] [logo]overlay=x= ' If (GTE (((t-2) *80)-w\,w, ((\,0\) t-2)-W) ': *80

3, every 10 seconds alternately appear logo.

Ffmpeg-y-T 60-i jidu.mp4-i logo.png-i Logo2.png-filter_complex "overlay=x=if (LT (mod (t\,20) \,10) \,10\,NAN): Y=10,over Lay=x=if (GT (mod (t\,20) \,10) \,w-w-10\,nan): y=10 "Overlay.mp4

Information

FFmpeg official website: http://www.ffmpeg.org

FFmpeg doc:http://www.ffmpeg.org/documentation.html

FFmpeg Wiki:https://trac.ffmpeg.org/wiki

FAQ

thanks!

FFmpeg Foundation: http://wenku.baidu.com/view/296eefcaf90f76c661371af1.html

Turn: FFmpeg basic usage