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• How do I use ffmpeg to concatenate 2 videos and add a period of silence + black screen between them ?

  29 avril 2022, par masotime

  There are several existing examples, but I'd like a single command that uses complex_filter to achieve the objective without doing extra things like generating blank video / audio files.

  


  Looking around, this is the best I've come up with so far :

  


  ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "color=black:s=960x540:d=1[b0];aevalsrc=0:d=1[s0];[0:v:0][0:a:0][b0][s0][1:v:0][1:a:0]concat=n=3:v=1:a=1[outv][outa]" -map '[outv]' -map '[outa]' out.mp4


  


  My understanding of the breakdown of such a command is

  


  

  1. specify 2 inputs

  


  2. define a complex filter

  


  3. define a black video stream of duration 1s and call it b0

  


  4. define a silent audio stream of duration 1s and call it s0

  


  5. pipe it through the concat filter with

  


  


  

  • First stream : [0:v:0][0:a:0] // video1.mp4

  


  • Second stream : [b0][s0] // stuff I defined earlier

  


  • Third stream : [1:v:0][1:a:0] // video2.mp4

  


  


  

  6. define 2 output streams [outv][outa] for video and audio respectively

  


  7. combine them into out.mp4

  


  


  All file inputs are correctly 960x540, all using the same audio and video codecs but ffmpeg gives me this error and starts using 100% CPU

  


  More than 1000 frames duplicated


  


  I think there's something wrong with the streams I'm defining in the filter - what's wrong ? Do I need to specify more parameters somewhere ?

  


  EDIT : Here's a MediaInfo printout of the input video's metadata

  


  Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/iso2/mp41)
File size                                : 7.82 MiB
Duration                                 : 31 s 449 ms
Overall bit rate                         : 2 086 kb/s
Writing application                      : Lavf59.16.100

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main@L3@Main
Codec ID                                 : hvc1
Codec ID/Info                            : High Efficiency Video Coding
Duration                                 : 31 s 449 ms
Bit rate                                 : 1 973 kb/s
Maximum bit rate                         : 2 000 kb/s
Width                                    : 960 pixels
Height                                   : 540 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0 (Type 0)
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.159
Stream size                              : 7.40 MiB (95%)
Writing library                          : x265 3.4+31-6722fce1f:[Mac OS X][clang 12.0.0][64 bit] 8bit+10bit+12bit
Encoding settings                        : cpuid=1111039 / frame-threads=4 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=960x540 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=3 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=23 / keyint=250 / gop-lookahead=0 / bframes=4 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=20 / lookahead-slices=0 / scenecut=40 / hist-scenecut=0 / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=3 / limit-refs=1 / no-limit-modes / me=1 / subme=2 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=3 / selective-sao=4 / early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=2.00 / psy-rdoq=0.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=abr / bitrate=2000 / qcomp=0.60 / qpstep=4 / stats-write=1 / stats-read=0 / slow-firstpass / ipratio=1.40 / pbratio=1.30 / aq-mode=2 / aq-strength=1.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=1 / overscan=0 / videoformat=5 / range=0 / colorprim=1 / transfer=1 / colormatrix=1 / chromaloc=1 / chromaloc-top=0 / chromaloc-bottom=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=255 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709
Codec configuration box                  : hvcC

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 31 s 449 ms
Source duration                          : 31 s 492 ms
Source_Duration_LastFrame                : -17 ms
Bit rate mode                            : Constant
Bit rate                                 : 106 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 405 KiB (5%)
Source stream size                       : 406 KiB (5%)
Title                                    : Core Media Audio
Language                                 : English
Default                                  : Yes
Alternate group                          : 1


  


• Wrong video information after encoding [closed]

  22 mars 2024, par Constadinos Chatzis

  Using FFMPEG for encoding videos from HDR to SDR with 3DLuts, i recently came to my attention that after the encoding the video has wrong information.

  


  The code i use is :
-vf lut3d="example.cube" -c:v libx265 -crf 16 -c:a copy -preset fast

  


  Original HDR video infos :

  


  General
Unique ID                      : 235922119201670445249046242281848857470 (0xB17CF2883DCE2BDE00E192235198637E)
Complete name                  : example.mkv
Format                         : Matroska
Format version                 : Version 4
File size                      : 201 MiB
Duration                       : 20 s 96 ms
Overall bit rate mode          : Variable
Overall bit rate               : 83.8 Mb/s
Frame rate                     : 16 343.153 FPS
Movie name                     : example
Writing application            : Lavf60.16.100
Writing library                : Lavf60.16.100
ErrorDetectionType             : Per level 1

Video
ID                             : 1
ID in the original source medi : 4113 (0x1011)
Format                         : HEVC
Format/Info                    : High Efficiency Video Coding
Format profile                 : Main 10@L5.1@High
HDR format                     : Dolby Vision, Version 1.0, Profile 7.6, dvhe.07.06, BL+EL+RPU, Blu-ray compatible / SMPTE ST 2086, Version HDR10, HDR10 compatible
Codec ID                       : V_MPEGH/ISO/HEVC
Duration                       : 20 s 96 ms
Bit rate                       : 66.3 Mb/s
Width                          : 3 840 pixels
Height                         : 2 160 pixels
Display aspect ratio           : 16:9
Frame rate mode                : Constant
Frame rate                     : 16 343.153 FPS
Original frame rate            : 23.976 (24000/1001) FPS
Color space                    : YUV
Chroma subsampling             : 4:2:0 (Type 2)
Bit depth                      : 10 bits
Bits/(Pixel*Frame)             : 0.000
Stream size                    : 106 GiB
Language                       : English
Default                        : No
Forced                         : No
Color range                    : Limited
Color primaries                : BT.2020
Transfer characteristics       : PQ
Matrix coefficients            : BT.2020 non-constant
Mastering display color primar : Display P3
Mastering display luminance    : min: 0.0050 cd/m2, max: 4000 cd/m2
Maximum Content Light Level    : 602 cd/m2
Maximum Frame-Average Light Le : 184 cd/m2
Original source medium         : Blu-ray


  


  After encoding to SDR the infos are :

  


  General
Unique ID                      : 197829821108483109262455008881990159019 (0x94D4A33C264AF154BCA17241DA23CAAB)
Complete name                  : example.mkv
Format                         : Matroska
Format version                 : Version 4
File size                      : 182 MiB
Duration                       : 20 s 62 ms
Overall bit rate mode          : Variable
Overall bit rate               : 76.1 Mb/s
Frame rate                     : 16 370.850 FPS
Movie name                     : example
Writing application            : Lavf60.16.100
Writing library                : Lavf60.16.100
ErrorDetectionType             : Per level 1

Video
ID                             : 1
ID in the original source medi : 4113 (0x1011)
Format                         : HEVC
Format/Info                    : High Efficiency Video Coding
Format profile                 : Format Range@L5@Main
HDR format                     : Dolby Vision, Version 1.0, Profile 7.6, dvhe.07.06, BL+EL+RPU, Blu-ray compatible
Codec ID                       : V_MPEGH/ISO/HEVC
Duration                       : 20 s 62 ms
Bit rate                       : 66.3 Mb/s
Width                          : 3 840 pixels
Height                         : 2 160 pixels
Display aspect ratio           : 16:9
Frame rate mode                : Constant
Frame rate                     : 16 370.850 FPS
Original frame rate            : 23.976 (24000/1001) FPS
Color space                    : RGB
Bit depth                      : 10 bits
Bits/(Pixel*Frame)             : 0.000
Stream size                    : 106 GiB
Writing library                : x265 3.5+113-8787af124:[Windows][GCC 13.2.0][64 bit] 10bit
Encoding settings              : cpuid=1111039 / frame-threads=4 / numa-pools=16 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=3 / input-res=3840x2160 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=3 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / temporal-layers=0 / open-gop / min-keyint=23 / keyint=250 / gop-lookahead=0 / bframes=4 / b-adapt=0 / b-pyramid / bframe-bias=0 / rc-lookahead=15 / lookahead-slices=8 / scenecut=40 / no-hist-scenecut / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=2 / limit-refs=3 / no-limit-modes / me=1 / subme=2 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=2 / selective-sao=4 / no-early-skip / rskip / fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=2.00 / psy-rdoq=0.00 / no-rd-refine / no-lossless / cbqpoffs=6 / crqpoffs=6 / rc=crf / crf=16.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=2 / aq-strength=1.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=1 / overscan=0 / videoformat=5 / range=1 / colorprim=9 / transfer=16 / colormatrix=0 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=1023 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass / no-mcstf / no-sbrc
Language                       : English
Default                        : No
Forced                         : No
Color range                    : Full
Color primaries                : BT.2020
Transfer characteristics       : PQ
Matrix coefficients            : Identity
Original source medium         : Blu-ray


  


  Is this normal ? Shouldn't the encoding file had different info's about color primaries, transfer characteristics etc ?

  


  Encoding video files i expected more accurate file informations.

  


• How do I write to a file in Golang using a pointer to the C data ?

  20 juillet 2020, par nevernew

  I'm writing an app for the windows platform using FFmpeg and it's golang wrapper goav, but I'm having trouble understanding how to use the C pointers to gain access to an array.

  



  I'm trying to write the frame data, pointed to by a uint8 pointer from C, to a .ppm file in golang.

  



  Once I have this done, for proof of concept that FFmpeg is doing what I expect it to, I want to set the frames to a texture in OpenGl to make a video player with cool transitions ; any pointers to do that nice and efficiently would be so very helpful ! I'm guessing I need to write some shader code to draw the ppm as a texture...

  



  The PPM file structure looks pretty simple just the header and then a byte of data for each red, green and blue value of each pixel in the frame from top left to bottom right

  



  I'm starting to understanding how to cast the pointers between C and Go types, but how can I access the data and write it in Go with the same result as C ? In C I just have to set the pointer offset for the data and state how much of it to write :

  



  for (y = 0; y < height; y++) {
    fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);
}


  



  I've stripped out all the relevant parts of the C code, the wrapper and my code, shown below :

  



  C code - libavutil/frame.h

  



  #include 

typedef struct AVFrame {
#define AV_NUM_DATA_POINTERS 8
    uint8_t *data[AV_NUM_DATA_POINTERS];
    int linesize[AV_NUM_DATA_POINTERS];
}


  



  Golang goav wrapper

  



  package avutil&#xA;&#xA;/*&#xA;    #cgo pkg-config: libavutil&#xA;    #include <libavutil></libavutil>frame.h>&#xA;    #include &#xA;*/&#xA;import "C"&#xA;import (&#xA;    "unsafe"&#xA;)&#xA;&#xA;type Frame C.struct_AVFrame&#xA;&#xA;func Data(f *Frame) *uint8 {&#xA;    return (*uint8)(unsafe.Pointer((*C.uint8_t)(unsafe.Pointer(&amp;f.data))))&#xA;}&#xA;func Linesize(f *Frame) int {&#xA;    return int(*(*C.int)(unsafe.Pointer(&amp;f.linesize)))&#xA;}&#xA;

  



  My Golang code

  



  package main

import "github.com/giorgisio/goav/avutil"

func saveFrame(videoFrame *avutil.Frame, width int, height int, iFrame int) {
    var szFilename string
    var y int
    var file *os.File
    var err error

    szFilename = ""

    // Open file
    szFilename = fmt.Sprintf("frame%d.ppm", iFrame)

    if file, err = os.Create(szFilename); err != nil {
        log.Println("Error Reading")
    }

    // Write header
    fh := []byte(fmt.Sprintf("P6\n%d %d\n255\n", width, height))
    file.Write(fh)
    var b byte = 0
    // Write pixel data
    for y = 0; y < height; y++ {
        d := avutil.Data(videoFrame) // d should be a pointer to the first byte of data
        l := avutil.Linesize(videoFrame)

        // I'm basically lost trying to figure out how to correctly write
        // this to a file, the file is created, but when I open it in GIMP
        // the image is mostly black with glitchy fuzz - so it's not being
        // written properly; the header seems to be ok, it knows the height
        // and width at least.

        data := make([]byte, l*3)

        ptr := unsafe.Pointer(d)
        for i := 0; i < l; i++ {
            datum := (*uint8)(unsafe.Pointer(uintptr(ptr) + (uintptr(i)+(uintptr(y)*uintptr(l)))*unsafe.Sizeof(*d)))
            data = append(data, *datum)
            //fmt.Println(*datum)
        }

        n, err := file.Write(data)
        if err != nil {
            log.Println("Error Writing:", szFilename, "-", n)
        }
    }

    file.Close()
}


  



  So, how can I write to a file using a pointer to the data, like you can do in C, and get the same result ?

  



  The first frame should be black so all 0's but I'm getting a glitchy fuzz, so it must be accessing some random data

  



  Update : My fix using a C function to save :

  



  package avutil&#xA;&#xA;/*&#xA;    #cgo pkg-config: libavutil&#xA;    #include <libavutil></libavutil>frame.h>&#xA;    #include &#xA;    #include &#xA;&#xA;    void SaveFrame(const char* location, AVFrame *pFrame, int width, int height) {&#xA;        FILE *pFile;&#xA;        int  y;&#xA;&#xA;        // Open file&#xA;        pFile=fopen(location, "wb");&#xA;        if(pFile==NULL)&#xA;            return;&#xA;&#xA;        // Write header&#xA;        fprintf(pFile, "P6\n%d %d\n255\n", width, height);&#xA;&#xA;        // Write pixel data&#xA;        for(y=0; ydata[0]&#x2B;y*pFrame->linesize[0], 1, width*3, pFile);&#xA;&#xA;        // Close file&#xA;        fclose(pFile);&#xA;    }&#xA;    uint8_t* GetData(AVFrame *pFrame) {&#xA;        return pFrame->data[0];&#xA;    }&#xA;*/&#xA;import "C"&#xA;

  



  I updated the avutil file, in the goav wrapper package, with this save function at the top, then pass it the frame context so it can get the data pointer from it. I also added this Go function to that avutil file to call the C function

  



  func SaveFrame(location string, f *Frame, width int, height int) {
    csLoc := C.CString(location)
    C.SaveFrame(csLoc, (*C.struct_AVFrame)(unsafe.Pointer(f)), C.int(width), C.int(height))
    C.free(unsafe.Pointer(csLoc))
}