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1. • 

     synthanatomy.com

     • Input devices are configured elements in FFmpeg which enable accessing the data coming from a multimedia device attached to your system. When you configure your FFmpeg build, all the supported input devices are enabled by default. You can list all available ones using the configure option "–list-indevs".
     ffmpeg.org › ffmpeg-devices

     FFmpeg Devices Documentation

2. Top results related to what are input devices in ffmpeg?

   • What are Input Devices?

     Input devices are the parts of the computer that we interact with daily and are used to input data to the computers. An input device is a hardware device that transfers data to a computer system and allows us to control it.

     What is an Input Device?

     The electromagnetic devices that accept data or a set of instructions from the outside world and then translate that data into machine-readable and understandable form are known as input devices. Computer input devices serve as an interface between the outside world and the computer for proper communication. When the users enter data using various input devices, the data can be saved in computer memory for further processing and preparation. Using the output devices, the intended and calculated results can be acquired when the processing and handling are completed. An input device transmits data to a computer and allows you to communicate with it and control it.

     Different Types of Input Devices

     Various types of Input Devices are,

     Keyboard

     For entering data into a computer, the keyboard is the most common and commonly used input device. It contains various keys for...

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     1/5

   • ffmpeg.c what are pts and dts ? what does this code block do in ffmpeg.c?

     Top Answer

     Answered Feb 19, 2014 · 167 votes

     Those are the decoding time stamp (DTS) and presentation time stamp (PTS). You can find an explanation here inside a tutorial.

     So let's say we had a movie, and the frames were displayed like: I B B P. Now, we need to know the information in P before we can display either B frame. Because of this, the frames might be stored like this: I P B B. This is why we have a decoding timestamp and a presentation timestamp on each frame. The decoding timestamp tells us when we need to decode something, and the presentation time stamp tells us when we need to display something. So, in this case, our stream might look like this:

     PTS: 1 4 2 3 DTS: 1 2 3 4Stream: I P B B-

     Generally the PTS and DTS will only differ when the stream we are playing has B frames in it.

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     2/5

   • What are bitstream filters in ffmpeg?

     Top Answer

     Answered Aug 16, 2015 · 52 votes

     Let me explain by example. FFmpeg video decoders typically work by converting one video frame per call to avcodec_decode_video2. So the input is expected to be "one image" worth of bitstream data. Let's consider this issue of going from a file (an array of bytes of disk) to images for a second.

     For "raw" (annexb) H264 (.h264/.bin/.264 files), the individual nal unit data (sps/pps header bitstreams or cabac-encoded frame data) is concatenated in a sequence of nal units, with a start code (00 00 01 XX) in between, where XX is the nal unit type. (In order to prevent the nal data itself to have 00 00 01 data, it is RBSP escaped.) So a h264 frame parser can simply cut the file at start code markers. They search for successive packets that start with and including 00 00 01, until and excluding the next occurence of 00 00 01. Then they parse the nal unit type and slice header to find which frame each packet belongs to, and return a set of nal units making up one frame as input to the h264 decoder.

     H264 data in .mp4 files is different, though. You can imagine that the 00 00 01 start code can be considered redundant if the muxing format already has length markers in it, as is the case for mp4. So, to save 3 bytes per frame, they remove the 00 00 01 prefix. They also put the PPS/SPS in the file header instead of prepending it before the first frame, and these also miss their 00 00 01 prefixes. So, if I were to input this into the h264 decoder, which expects the prefixes for all nal units, it wouldn't work. The h264_mp4toannexb bitstream filter fixes this, by identifying the pps/sps in the extracted parts of the file header (ffmpeg calls this "extradata"), prepending this and each nal from individual frame packets with the start code, and concatenating them back together before inputting them in the h264 decoder.

     You might now feel that there's a very fine line distinction between a "parser" and a "bitstream filter". This is true. I think the official definition is that a parser takes a sequence of input data and splits it in frames without discarding any data or adding any data. The only thing a parser does is change packet boundaries. A bitstream filter, on the other hand, is allowed to actually modify the data. I'm not sure this definition is entirely true (see e.g. vp9 below), but it's the conceptual reason mp4toannexb is a BSF, not a parser (because it adds 00 00 01 prefixes).

     Other cases where such "bitstream tweaks" help keep decoders simple and uniform, but allow us to support all files variants that happen to exist in the wild:

     • mpeg4 (divx) b frame unpacking (to get B-frames sequences like IBP, which are coded as IPB, in AVI and get timestamps correct, people came up with this concept of B-frame packing where I-B-P / I-P-B is packed in frames as I-(PB)-(), i.e. the third packet is empty and the second has two frames. This means the timestamp associated with the P and B frame at the decoding phase is correct. It also means you have two frames worth of input data for one packet, which violates ffmpeg's one-frame-in-one-frame-out concept, so we wrote a bsf to split the packet back in two - along with deleting the marker that says that the packet contains two frames, hence a BSF and not a parser - before inputting it into the decoder. In practice, this solves otherwise hard problems with frame multithreading. VP9 does the same thing (called superframes), but splits frames in the parser, so the parser/BSF split isn't always theoretically perfect; maybe VP9's should be called a BSF)
     • hevc mp4 to annexb conversion (same story as above, but for hevc)
     • aac adts to asc conversion (this is basically the same as h264/hevc annexb vs. mp4, but for aac audio)

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     3/5

   • What are the differences between the formats "matroska", "matroska,webm" and "webm" in ffmpeg?

     Top Answer

     Answered Nov 22, 2021 · 4 votes

     WebM is a subset of Matroska, so there's one module (demuxer / muxer) that handles their reading & writing respectively. The middle name matroska,webm is the name of the ffmpeg demuxer that reads both Matroska and WebM files. It is specific to ffmpeg and does not represent any variant or unique format.

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     4/5

   • What are types for input events in Vue

     Top Answer

     Answered Aug 28, 2020 · 26 votes

     Thanks to @steve16351 answer in the comments, there is summary:

     For keyboard event like keypress you can use more specific event from Event -> UIEvent -> KeyboardEvent:

     <input @keypress="handleKeypress" />-handleKeypress(e: KeyboardEvent) { }

     For more specific event like input change on HTMLInputElement you need to cast it:

     <input @input="handleInput" />-handleInput(e: Event) { const target = (<HTMLInputElement>e.target) console.log(target.value)}

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     5/5

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3. ffmpeg.org · ffmpeg-devicesFFmpeg Devices Documentation

   ffmpeg.org · ffmpeg-devices

   

   2 days ago · Input devices are configured elements in FFmpeg which enable accessing the data coming from a multimedia device attached to your system. When you configure your FFmpeg build, all the supported input devices are enabled by default. You can list all available ones using the configure option "–list-indevs".

   • Ffmpeg Devices Documentation

     3 Input Devices. Input devices are configured elements in...

   • Ffmpeg Documentation

     ffmpeg reads from an arbitrary number of input "files"...

   • All

     ffmpeg [global_options] {[input_file_options] -i input_url}...

4. People also ask

   What are input devices in FFmpeg?

   • Input devices are configured elements in FFmpeg which enable accessing the data coming from a multimedia device attached to your system. When you configure your FFmpeg build, all the supported input devices are enabled by default. You can list all available ones using the configure option "–list-indevs".

   FFmpeg Devices Documentation

   ffmpeg.org/ffmpeg-devices.html

   See all results for this question

   What does FFmpeg -sources do?

   • Defaults to false. This option is deprecated, please use the -sources option of ffmpeg to list the available input devices. If set to true, print a list of supported formats and exit. Defaults to false. This sets the input video format to the format given by the FourCC. To see the supported values of your device (s) use list_formats.

   ffmpeg Documentation

   ffmpeg.org/ffmpeg-all.html

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   What is the default value for output devices in FFmpeg?

   • The default value for both options is 0. Output devices are configured elements in FFmpeg that can write multimedia data to an output device attached to your system. When you configure your FFmpeg build, all the supported output devices are enabled by default. You can list all available ones using the configure option "–list-outdevs".

   FFmpeg Devices Documentation

   ffmpeg.org/ffmpeg-devices.html

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   Does FFmpeg support DirectShow?

   • Windows DirectShow input device. DirectShow support is enabled when FFmpeg is built with the mingw-w64 project. Currently only audio and video devices are supported. Multiple devices may be opened as separate inputs, but they may also be opened on the same input, which should improve synchronism between them. The input name should be in the format:

   FFmpeg Devices Documentation

   ffmpeg.org/ffmpeg-devices.html

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5. ffmpeg.org · ffmpegffmpeg Documentation

   ffmpeg.org · ffmpeg

   

   • Example: Automatic Stream Selection
   • Example: Automatic Subtitles Selection
   • Example: Unlabeled Filtergraph Outputs
   • Example: Labeled Filtergraph Outputs

   There are three output files specified, and for the first two, no -mapoptionsare set, so ffmpeg will select streams for these two files automatically. out1.mkv is a Matroska container file and accepts video, audio and subtitle streams,so ffmpeg will try to select one of each type. For video, it will select stream 0 from B.mp4, which has the highest...

   See full list on ffmpeg.org

   Although out1.mkv is a Matroska container file which accepts subtitle streams, only avideo and audio stream shall be selected. The subtitle stream of C.mkv is image-basedand the default subtitle encoder of the Matroska muxer is text-based, so a transcode operationfor the subtitles is expected to fail and hence the stream isn’t selected. However, in...

   See full list on ffmpeg.org

   A filtergraph is setup here using the -filter_complex option and consists of a singlevideo filter. The overlay filter requires exactly two video inputs, but none arespecified, so the first two available video streams are used, those of A.avi andC.mkv. The output pad of the filter has no label and so is sent to the first output fileout1.mp4. Due to ...

   See full list on ffmpeg.org

   The above command will fail, as the output pad labelled [outv]has been mapped twice.None of the output files shall be processed. This command above will also fail as the hue filter output has a label, [outv],and hasn’t been mapped anywhere. The command should be modified as follows, The video stream from B.mp4is sent to the hue filter, whose output...

   See full list on ffmpeg.org

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7. stackoverflow.com · questions · 46447230ffdshow - FFmpeg dshow device format list - Stack Overflow

   stackoverflow.com · questions · 46447230

   

   Sep 27, 2017 · On Windows, I am able to get device list. ffmpeg -list_devices true -f dshow -i dummy. and device options. ffmpeg -f dshow -list_options true -i video="MY_DSHOW_DEVICE_NAME". But I am not able to get format list, like on Linux via v4l2.

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9. shotstack.io · learn · how-to-use-ffmpegHow to use FFmpeg (with examples) - Shotstack

   shotstack.io · learn · how-to-use-ffmpeg

   

   Feb 5, 2024 · FFmpeg is a free and open-source video and audio processing tool that you run from the command-line. FFmpeg is the tool of choice choice for multiple reasons: Free: It's a completely free option. Open-source: It has an active and dedicated open-source community continually deploying fixes, improvements, and new features.

10. ffmpeg.org · ffmpeg-allffmpeg Documentation

    ffmpeg.org · ffmpeg-all

    

    ffmpeg [global_options] {[input_file_options] -i input_url} ... {[output_file_options] output_url} ... 2 Description. ffmpeg is a universal media converter. It can read a wide variety of inputs - including live grabbing/recording devices - filter, and transcode them into a plethora of output formats.

11. ffmpeg-api.com · learn · ffmpegMastering FFmpeg Command Syntax: An In-Depth Guide

    ffmpeg-api.com · learn · ffmpeg

    

    FFmpeg is a powerful tool for handling multimedia data. Its command-line interface allows for a wide range of operations, including conversion, encoding, filtering, and more. This guide will delve deep into the FFmpeg command syntax, providing examples that cover complex scenarios and edge-cases.

12. superuser.com · questions · 242584command line - How to provide multiple input to ffmpeg ...

    superuser.com · questions · 242584

    

    As input I have images named 001.jpg, 002.jpg, etc. and then with the command. ffmpeg -i %3d.jpg -sameq -s 1440x1080 video.mp4. I create the video. But my problem comes when I want to create a video using multiple sets as input.