Basic FFMPEG usage (transfer)

FFmpeg

FFmpeg basic usage

Problems to be Solved in this lesson

1. What is the FFMPEG transcoding process?

2. What content does a common video format contain?

3. How to extract the content from a video file?

4. How to convert from one format to another?

5. How to zoom in and out a video?

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

7. How to add a logo to the video and delete the logo?

8. How to add text and dynamic text to a video?

9. How to process images?

10. How to video, add dynamic logos, and mosaic videos?

Part 1

Basic

Terms

Container)

A container is a file format, such as FLV and MKV. Contains the following five streams and file header information.

Stream)

It is a transmission of video data information. Five streams are used: audio, video, subtitle, attachment, and data.

Frame)

Frames represent a static image, which can be divided into I frame, P frame, and B frame.

Codec)

Is to compress or decompress the video, codec = Code (encoding) + decode (Decoding)

Multiplexing/demultiplexing (MUX/Demux)

Put different streams into containers according to certain container rules. This behavior is called multiplexing (MUX)

Parse different streams from a container. This behavior is called Demux)

 

 

Introduction

 

The name of FFMPEG comes from the MPEG video encoding standard. The previous "FF" indicates "Fast Forward". FFmpeg is a set of functions that can be used to record and convert digital audios and videos, and can be converted into open-source computer programs of the stream. You can easily convert multiple video formats.

 

FFmpeg users include Google, Facebook, YouTube, Youku, iQiYi, and Tudou.

Composition

1. libavformat: used to generate and parse audio and video encapsulation formats, including obtaining the information required for decoding to generate the decoding Context Structure and reading audio and video frames, including demuxers and muxer libraries;

2. libavcodec: used for various types of sound/Image Coding/decoding;

3. libavutil: contains some common tool functions;

4. libswscale: used for proportional scaling and color ing conversion in video scenarios;

5. libpostproc: used for post-effect processing;

6. FFMPEG: it is a command line tool used to convert the video file format. It also supports real-time Encoding of video cards;

7. ffsever: an HTTP multimedia real-time broadcast stream server that supports time translation;

8. ffplay: A simple player that uses the FFMPEG library for parsing and decoding and is displayed through SDL;

 

FFmpeg Process

Filter)

In multimedia processing, filter indicates a software tool used to modify the content of an input file before being encoded into an output file. Such as video flip, rotation, and scaling.

Syntax: [input_link_label1] [input_link_label2]… Filter_name = parameters [output_link_label1] [output_link_label2]…

Filter chart link label: indicates the name of the input or output of the filter.

1. Video filter-VF

For example, the testsrc video is rotated 90 degrees clockwise.

Ffplay-F lavfi-I testsrc-VF transpose = 1

For example, testsrc video horizontal flip (left and right flip)

Ffplay-F lavfi-I testsrc-VF hflip

2. audio filter-AF

Implements Slow playback. The sound speed is 50% of the original speed.

Ffplay p629100108- af atempo = 0.5

 

How to rotate 90 degrees clockwise and flip horizontally?

Filter chain)

Basic syntax

Filterchain = a comma-separated filter group

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 to compare the horizontal Flip video and source video? See how the filter chain is implemented.

 

 

 

 

 

 

Filter chain)

Step 1: double the width of the source video.

FFmpeg-I jidu.mp4-T 10-VF pad = 2 * IW output.mp4

Step 2: horizontal flip of the Source Video

FFmpeg-I jidu.mp4-T 10-VF hflip output2.mp4

Step 3: Cover output.mp4 with a horizontal Flip video

FFmpeg-I output.mp4-I output2.mp4-filter_complex overlay = W compare.mp4

Is it complicated?

You only need one command to use filtergraph.

Filter graph)

Basic syntax

Filtergraph = a set of filterchains separated by semicolons

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

 

 

Filtergraph Classification

1. simple one-to-one

2. Complex (complex) Multi-to-one, multi-to-many

Filter graph)

Simple filter chart processing process:

 

 

Complex filter chart processing process:

 

 

 

It can be found that the complex filter diagram has two steps less than the simple filter diagram, and the efficiency is higher than the simple filter diagram. We recommend that you use the complex filter diagram whenever possible.

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

 

Filter graph)

Use ffplay to directly view the results:

Ffplay-F lavfi-I testsrc-VF split [a] [B]; [a] pad = 2 * IW [1]; [B] hflip [2]; [1] [2] overlay = W

 

 

 

 

F1: The split filter creates copies of two input files and marks them as [a], [B]

F2: [a] as the input of the pad filter, the pad filter generates 2 times the width and outputs it to [1].

F3: [B] as the input of hflip filter, vflip filters flip the video horizontally and output it to [2].

F4: Use the overlay filter to overwrite [2] to the side of [1.

 

 

Select a media stream

Some multimedia containers, such as Avi, MKV, and MP4, can contain multiple streams of different types. How can we extract various streams from the container?

Syntax:

-Map file_number: stream_type [: stream_number]

 

Here are some special stream symbols:

1.-map 0 Selects all streams of the first file

2.-map I: V obtains all video streams from the file No. I (INDEX),-map I: A gets all audio streams,-map I: s gets all subtitle streams, and so on.

3. Special parameters-An,-VN, and-Sn are used to exclude all audio, video, and Subtitle streams.

 

Note: The file sequence number and stream sequence number are counted from 0.

Select a media stream

Part 2

View help

Help

The FFMPEG tool has a huge Console Help. The following table describes available options. Italics indicate the items to be replaced, and ffplay and ffprobe have similar options.

 

Help

Available bit stream: FFMPEG-BSFs

Available codecs: FFMPEG-codecs

Available decoder: FFMPEG-decoders

Available encoders: FFMPEG-encoders

Available filter: FFMPEG-Filters

Available video formats: FFMPEG-formats

Available Channel Layout: FFMPEG-layouts

Available license: FFMPEG-l

Available pixel format: FFMPEG-pix_fmts

Available Protocol: FFMPEG-protocals

 

Part 3

Bit Rate, frame rate, and file size

Overview

Bit Rate and frame rate are the most important basic features of video files. Their special settings determine the video quality. If we know the bit rate and duration, we can easily calculate the size of the output file.

 

Frame Rate: The frame rate is also called the frame frequency. The frame rate is the number of frames per second in a video file. To see a continuously moving image, you need at least 15 frames.

Bit Rate: Bit Rate (also called bit rate, data rate) is a parameter for determining the overall video/audio quality. The number of bytes processed per second is proportional to the video quality, BPS is used to express the bit rate in a video file.

Frame Rate

1. Use the-R parameter to set the Frame Rate

FFmpeg-I input-r FPS output

2. Use FPS filter to set the Frame Rate

FFmpeg-I clip. mpg-VF FPS = 25 clip. webm

Pre-defined value of frame rate:

 

 

 

 

 

For example, if the bitrate is set to 29.97fps, the following three methods have the same results:

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

 

Bit Rate and file size

Set bitrate-parameter B

-B

FFmpeg-I film. Avi-B 1.5 m film.mp4

 

Audio:-B: A Video:-B: V

Set the video bit rate to 1500 kbps.

FFmpeg-I input. Avi-B: V 1500 K output.mp4

 

Control output file size

-FS (abbreviation of file size)

FFmpeg-I input. Avi-Fs 1024 K output.mp4

Calculate the output file size

(Video bit rate + audio bit rate) * duration/8 = file size k

 

 

Part 4

Adjust video resolution

Adjust video resolution

1. Use the-S parameter to set the video resolution. The parameter value is WXH. The unit of W width is pixel, and the unit of H height is pixel.

FFmpeg-I input_file-s 320x240 output_file

 

2. predefined 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 predefined dimensions.

 

 

 

 

Scale filter to adjust resolution

The advantage of scale filter is that some additional parameters can be used.

Syntax:

Scale = width: height [: interl = {1 |-1}]

The following table lists common additional parameters.

Example

The following two commands have the same effect

FFmpeg-I input. mpg-s 320x240 output.mp4

FFmpeg-I input. mpg-VF scale = 320: 240 output.mp4

 

Proportional scaling of input videos

Change to half size of Source Video

FFmpeg-I input. mpg-VF scale = IW/2: ih/2 output.mp4

Change to 90% of the original video size:

FFmpeg-I input. mpg-VF scale = IW * 0.9: ih * 0.9 output.mp4

 

Example

When the resolution of an unknown video is used, make sure that the adjusted resolution is consistent with that of the source video.

Fixed width 400, height proportional:

FFmpeg-I input. Avi-VF scale = 400: 400/

FFmpeg-I input. Avi-VF scale = 400:-1

 

On the contrary, 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

 

Part 5

Crop/fill video

Crop video crop Filter

Selecting the desired rectangular area from the input file to the output file is often used to remove the Black edge of the video.

Syntax: crop: Ow [: Oh [: X [: Y: [: keep_aspect]

 

Example

Crop the left 1/3, middle 1/3, and right 1/3 of the input video:

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

Center of the cropped Frame

When we want to crop the area in the middle of the frame, the cropping filter can skip the input x and y values. 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 the middle half of the area:

FFmpeg-I input. Avi-VF crop = IW/2: ih/2 output. Avi

 

Example

Compare the cropped video and Source Video

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

 

 

Auto-detect crop area

Cropdetect filter automatically detects Black edge areas

Ffplay jidu.mp4-VF cropdetect

 

 

 

 

Then, use the detected value to crop the video.

Ffplay jidu.mp4-VF crop = 672: 272: 0: 54

 

 

Pad)

Adds a fast additional area to the video frame, which is often used to display different vertical/horizontal ratios during playback.

Syntax: pad = width [: Height: [: X [: Y: [: Color]

 

 

Example

Create a 30-pixel pink width to enclose an image of svga size:

FFmpeg-I photo.jpg-VF pad = 860: 660: 30: 30: pink framed_photo.jpg

?

 

 

 

Similarly, you can create a video named testsrc and enclose the video with 30 pixels in pink.

Ffplay-F lavfi-I testsrc-VF pad = IW + 60: ih + 60: 30: 30: pink

 

To

Some devices can only play the ratio. The ratio must be filled with on both sides of the horizontal direction,

 

The height is maintained, and the width equals to the height multiplied by 16/9. The X (horizontal displacement of the input file) value is calculated by the expression (output_width-input_width)/2.

 

The general commands from to 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

 

PM to PM

To display the ratio of X to Y at, fill in the vertical sides of the input file, and keep the width unchanged. The height is 3/4 of the width and Y value (the vertical offset of the input file) is calculated by an expression (output_height-input_height)/2.

 

General commands from PM to PM:

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

 

 

Part 6

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

 

Rotate

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

0: Rotate 90 ° counterclockwise and flip vertically

1: Rotate 90 ° clockwise

2: Rotate 90 ° counterclockwise

3: Rotate 90 ° clockwise and then flip horizontally

Part 7

Blur and 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 radius of luma_r and alpha_r ranges from 0 ~ Min (W, h)/2, the range of chroma_r radius is 0 ~ Min (CW/CH)/2

Sharpen

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

All parameters are optional. The default value is. 0: 5: 5: 0.0.

L_msize_x: horizontal brightness matrix, value range: 3-13, default value: 5

L_msize_y: vertical brightness matrix, value range: 3-13, default value: 5

Rochelle amount: brightness intensity. value range:-2.0-5.0. The negative number indicates the blur effect. The default value is 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. The negative number indicates the blur effect. The default value is 0.0.

Example

Use the default value. The brightness matrix is 5x5 and the brightness value is 1.0.

FFmpeg-I input-VF unsharp output.mp4

Gaussian blur effect (strong fuzzy ):

Ffplay-F lavfi-I testsrc-VF unsharp = 13: 13:-2

 

Part 8

Overwrite (in-picture)

Overwrite

Syntax: overlay [= x [: Y]

All parameters are optional. The default value is 0.

 

Example

The logo is in the upper 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:

FFmpeg-I pair.mp4-I logo.png-filter_complex overlay = 0: H-H pair2.mp4

Bottom right corner:

FFmpeg-I pair.mp4-I logo.png-filter_complex overlay = W-W: H-H pair2.mp4

 

Delete logo

Syntax:-VF delogo = x: Y: W: H [: T [: Show]

X: Y coordinate from the upper left corner

W: H logo width and height

T: The thickness of the rectangular edge. The default value is 4.

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

Ffplay-I jidu.mp4-VF delogo = 50: 51: 60: 60: 100: 0

Part 9

Add text

Add text

Syntax:

Drawtext = fontfile = font_f: text = text1 [: P3 = V3 [: P4 = V4 […]

Common parameter values

X: the abscissa from the upper left corner.

Y: vertical coordinate from the upper left corner

Fontcolor: font color

Fontsize: font size

Text: Text Content

Textfile: Text File

T: Timestamp, in seconds

N: the starting position of the number of frames is 0.

Draw/enable: display the control file. If the value is 0, it is not displayed. If the value is 1, you can use the function.

Simple usage

1. Add the welcome text in the upper 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

Use the T (time second) variable to implement dynamic text

1. horizontal scrolling at the top

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: textfile1_textfile.txt: x = W-T * 50: Y = H-TH: fontcolor = darkorange: fontsize = 30"

3. vertical scroll up from bottom

Ffplay jidu.mp4-VF drawtext = "textfile = textfile: fontfile = Arial. TTF: x = (W-tw)/2: Y = h-t * 100: fontcolor = white: fontsize = 30"

Do you want to display the current time in the upper-right corner?

 

 

Dynamic text

Display the current time localtime in the upper right corner

Ffplay jidu.mp4-VF drawtext = "fontfile = Arial. TTF: x = W-TW: fontcolor = white: fontsize = 30: text = '% {localtime \: % H \: % m \\\: % s}'

 

Display 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 )"

 

Part 10

Image Processing

Image Support

FFmpeg supports the vast majority of image processing, except ljpeg (lossless JPEG), which can be decoded. All except EXR, PIC, and PTx can be encoded.

Use the-SS (seek from start) parameter to intercept an image.

FFmpeg-SS 01:23:45-I jidu.mp4 image.jpg

Generate GIF images from videos

FFmpeg-I jidu.mp4-T 10-pix_fmt rgb24 jidu.gif

Convert a video to an image (one image per frame)

FFmpeg-I clip. Avi frame00004d.jpg

Convert an image to a video

FFmpeg-F image2-I img3164d.jpg-R 25 video.mp4

 

Cropping and filling

Like videos, images can be cropped and filled.

Crop

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

Images can be flipped, rotated, and overwritten like videos.

Flip

FFmpeg-I orange.jpg-VF hflip orange_hfilp.jpg

FFmpeg-I orange.jpg-VF vflip orange_vfilp.jpg

Rotate

FFmpeg-I image.png-VF transpose = 1 image_rotated.png

Overwrite

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

 

Part 1

Other advanced skills

Screen recording

Display Device Name

FFmpeg-list_devices 1-F dshow-I dummy

Call the 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 800 K-vcodec MPEG4 new.mp4

 

Add subtitle subtitles

Syntax-VF Subtitles = File

 

FFmpeg-I jidu.mp4-VF Subtitles = RGB. srt output.mp4

Video trembling and color balancing

Video trembling

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/white

Ffplay-I jidu.mp4-VF lutyuv = "u = 128: V = 128"

Set the audio/video playback speed

3X video playback

Ffplay-I jidu.mp4-VF setpts = pts/3

? Video playback speed

Ffplay-I jidu.mp4-VF setpts = pts/(3/4)

Playback of audio at 2x speed

Ffplay-I speech.mp3-AF atempo = 2

 

Problem: video and audio are simultaneously played at a speed of 3/4

Cut a graph every second

FFmpeg-I input. FLV-F image2-VF FPS = 1 outputted d.png

Screenshot every 20 seconds

FFmpeg-I input. FLV-F image2-VF FPS = 1/20 out0000d.png

 

Note: The FFMPEG version N-57961-gec8e68c version can cut a graph every 20 s at most.

Merge multiple files into one file (2x3 )? Capture a graph every one thousand frames (in seconds = 1000/fps25)

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

After 1 and 2 seconds, the logo will be moved from left to right:

Ffplay-I jidu.mp4-VF moview.logo.png [logo]; [in] [logo] overlay = x = 'if (GTE (T \, 2) \, (t-2) * 80) -W \, Nan) ': Y = 0

 

2. After 2 seconds, the logo is moved from left to right and then stops in the upper left corner.

Ffplay-I jidu.mp4-VF moview.logo.png [logo]; [in] [logo] overlay = x = 'if (GTE (t-2) * 80)-w \, W) \, 0 \, (t-2) * 80)-W) ': Y = 0

3. The logo appears every 10 seconds.

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, overlay = x = If (GT (mod (T \, 20) \, 10) \, W-w-10 \, Nan ): y = 10 "overlay.mp4

 

Materials

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 basics: http://wenku.baidu.com/view/296eefcaf90f76c661371af1.html

Original post address: http://derekzhan.iteye.com/blog/1989274

Basic FFMPEG usage (transfer)