Recherche avancée
Médias (1)
-
DJ Dolores - Oslodum 2004 (includes (cc) sample of “Oslodum” by Gilberto Gil)
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
Autres articles (38)
-
L’utiliser, en parler, le critiquer
10 avril 2011La première attitude à adopter est d’en parler, soit directement avec les personnes impliquées dans son développement, soit autour de vous pour convaincre de nouvelles personnes à l’utiliser.
Plus la communauté sera nombreuse et plus les évolutions seront rapides ...
Une liste de discussion est disponible pour tout échange entre utilisateurs. -
Contribute to documentation
13 avril 2011Documentation is vital to the development of improved technical capabilities.
MediaSPIP welcomes documentation by users as well as developers - including : critique of existing features and functions articles contributed by developers, administrators, content producers and editors screenshots to illustrate the above translations of existing documentation into other languages
To contribute, register to the project users’ mailing (...) -
Publier sur MédiaSpip
13 juin 2013Puis-je poster des contenus à partir d’une tablette Ipad ?
Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir
Sur d’autres sites (4480)
-
How to optimize FFMPEG/ Chromacast video ?
5 août 2021, par HasanRe-broadcast a live broadcast by chromecasting it. The code below delays 5 seconds.


Server I use :
https://instances.vantage.sh/?selected=c5.2xlarge


Can you help me optimize the code ?


chromakey.sh



# Combine two files using a chromakey effects
filter_complex(){
 local videoWith="${1:-1920}" # Video Size
 local videoHeight="${2:-1080}" # Video Size
 local key="${3:-00FF00}" # Colorkey colour - default vaue is 0000FF or green
 local colorSim="${4:-0.2}" # Colorkey similarity level - default value is 0.2
 local colorBlend="${5:-0.1}" # Colorkey blending level - default value is 0.1

 # Update color variable according to user input
 # This makes the matching case insensitive
 if [[ $3 =~ ^[0-9A-F]{6}$ ]]; then
 key=$3
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "blue" ]]; then
 key="0000FF"
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "green" ]]; then
 key="00FF00"
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "red" ]]; then
 key="FF0000"
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "purple" ]]; then
 key="0000FF"
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "orange" ]]; then
 key="ff9900"
 elif [[ $(tr "[:upper:]" "[:lower:]" <<<"$1") = "yellow" ]]; then
 key="FFFF00"
 fi

 
 filterString="[1:v]scale=$videoWith x $videoHeight,chromakey=0 x $key:$colorSim:$colorBlend[ckout];[0:v]scale=(iw*sar)*max($videoWith/(iw*sar)\,$videoHeight/ih):ih*max($videoWith/(iw*sar)\,$videoHeight/ih), crop=$videoWith:$videoHeight[bg];[bg][ckout]overlay[out]"
 
 printf '%s%s%s%s%s' $filterString
}

ffmpeg -re -stream_loop -1 -i "${1}" -i "${2}" -preset ultrafast -filter_complex "$(filter_complex "${@:4}")" -map '[out]' -c:v libx264 -f flv "${3}"


Usage : ./chromakey.sh mask.mp4 http://example.com/live/broadcast_orj rtmp ://example.com/live/broadcast_greenscreen 1920 1080 green 0.1 0.2


-
ffmpeg transparent png frames to webm gets autocropped and opaque instead of showing the input frames
26 mai 2022, par Regdai got a webm file that outputs transparency as black if transparency is not supported, but unpacking the webm file to png frames outputs the pngs with transparency.
I tried to repack the transparent png frames into a webm file that behaves like described above (transparent but black if not supported).


The current issue (where i need help) is that it looks like ffmpeg applies some sort of optimization, which creates an area filled with an analyzed color, cropping it to the size of the opaque content/pixels and leaving the rest white.

And i don't want this.

Related to VLC the metadata of the original says that
Lavc58.65.102 libvpx-vp9was used as encoder and that the Stream0 has the following informations :

Codec: Google/On2's VP9 Video (VP90)
Language: English
Type: Video
Video resolution: 816x624
Buffer dimensions: 816x640
Frame rate: 30.000300
Decoded format: Planar 4:2:0 YUV
Orientation: Top left


To reproduce the issue i created 2 transparent frames (a green and a blue cross) where the opaque content is smaller then the image size and copied them 10-times to be able to actually preview the webm file in vlc, the 2 frames do look like below :



Then i clicked together the following ffmpeg command and executed it :

ffmpeg -framerate 30 -t 7.2 -i frames/%04d.png -b:v 1307k -c:v libvpx-vp9 -color_range 1 -pix_fmt yuva420p -metadata:s:v:0 alpha_mode="1" out.webm
(changing the pixel format e.g. from yuv to yuva doesn't seem to change anything)

ffmpeg console output :


ffmpeg version N-102605-g4c705a2775 Copyright (c) 2000-2021 the FFmpeg developers
 built with gcc 10-win32 (GCC) 20210408
 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-version3 --disable-debug --enable-shared --disable-static --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --enable-amf --enable-libaom --disable-avisynth --enable-libdav1d --disable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --disable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libvidstab --disable-libx264 --disable-libx265 --disable-libxavs2 --disable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp
 libavutil 57. 0.100 / 57. 0.100
 libavcodec 59. 1.100 / 59. 1.100
 libavformat 59. 2.101 / 59. 2.101
 libavdevice 59. 0.100 / 59. 0.100
 libavfilter 8. 0.101 / 8. 0.101
 libswscale 6. 0.100 / 6. 0.100
 libswresample 4. 0.100 / 4. 0.100
Input #0, image2, from 'frames/%04d.png':
 Duration: 00:00:00.67, start: 0.000000, bitrate: N/A
 Stream #0:0: Video: png, rgba(pc), 816x624 [SAR 2835:2835 DAR 17:13], 30 fps, 30 tbr, 30 tbn
Stream mapping:
 Stream #0:0 -> #0:0 (png (native) -> vp9 (libvpx-vp9))
Press [q] to stop, [?] for help
[libvpx-vp9 @ 000001c97b52b000] v1.10.0
Output #0, webm, to 'out.webm':
 Metadata:
 encoder : Lavf59.2.101
 Stream #0:0: Video: vp9, yuv420p(tv, progressive), 816x624 [SAR 1:1 DAR 17:13], q=2-31, 1307 kb/s, 30 fps, 1k tbn
 Metadata:
 alpha_mode : 1
 encoder : Lavc59.1.100 libvpx-vp9
 Side data:
 cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame= 20 fps=0.0 q=0.0 Lsize= 2kB time=00:00:00.63 bitrate= 21.5kbits/s speed=1.09x
video:1kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 68.316833%


an playback of the webm file in vlc shows something totaly different, the area of the cross is filled in its color and the rest is white where it all should be black and transparent if possible (yes i know in vlc it's not possible...) :



It would be nice to have an ffmpeg command that does produce the expected result (webm video showing a cross on black/transparent background)


PS : Related to the Title of this post : I don't know how this issue is called, so feel free to edit the Title, im out of ideas.


-
FFmpeg conversion RGB to YUV420 to RGB wrong result
29 août 2020, par sipwizI'm attempting to sort out a video encoding issue and along the way making sure I can convert between pixel formats with FFmpeg. I'm having a problem converting a dummy RGB24 bitmap to YUV420 and back again.


Below is my test program :


#include "Windows.h"

#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavformat></libavformat>avio.h>
#include <libavutil></libavutil>imgutils.h>
#include <libswscale></libswscale>swscale.h>
#include <libavutil></libavutil>time.h>

#define WIDTH 32
#define HEIGHT 32
#define ERROR_LEN 128
#define SWS_FLAGS SWS_BICUBIC

char _errorLog[ERROR_LEN];
void CreateBitmapFile(LPCWSTR fileName, long width, long height, WORD bitsPerPixel, BYTE* bitmapData, DWORD bitmapDataLength);

int main()
{
 printf("FFmpeg Pixel Conversion Test\n");

 av_log_set_level(AV_LOG_DEBUG);

 int w = WIDTH;
 int h = HEIGHT;

 struct SwsContext* rgbToI420Context;
 struct SwsContext* i420ToRgbContext;

 rgbToI420Context = sws_getContext(w, h, AV_PIX_FMT_RGB24, w, h, AV_PIX_FMT_YUV420P, SWS_FLAGS, NULL, NULL, NULL);
 if (rgbToI420Context == NULL) {
 fprintf(stderr, "Failed to allocate RGB to I420 conversion context.\n");
 }

 i420ToRgbContext = sws_getContext(w, h, AV_PIX_FMT_YUV420P, w, h, AV_PIX_FMT_RGB24, SWS_FLAGS, NULL, NULL, NULL);
 if (i420ToRgbContext == NULL) {
 fprintf(stderr, "Failed to allocate I420 to RGB conversion context.\n");
 }

 // Create dummy bitmap.
 uint8_t rgbRaw[WIDTH * HEIGHT * 3];
 for (int row = 0; row < 32; row++)
 {
 for (int col = 0; col < 32; col++)
 {
 int index = row * WIDTH * 3 + col * 3;

 int red = (row < 16 && col < 16) ? 255 : 0;
 int green = (row < 16 && col > 16) ? 255 : 0;
 int blue = (row > 16 && col < 16) ? 255 : 0;

 rgbRaw[index] = (byte)red;
 rgbRaw[index + 1] = (byte)green;
 rgbRaw[index + 2] = (byte)blue;
 }
 }

 CreateBitmapFile(L"test-reference.bmp", WIDTH, HEIGHT, 24, rgbRaw, WIDTH * HEIGHT * 3);

 printf("Converting RGB to I420.\n");

 uint8_t* rgb[3];
 uint8_t* i420[3];
 int rgbStride[3], i420Stride[3];

 rgbStride[0] = w * 3;
 i420Stride[0] = w * h;
 i420Stride[1] = w * h / 4;
 i420Stride[2] = w * h / 4;

 rgb[0] = rgbRaw;
 i420[0] = (uint8_t*)malloc((size_t)i420Stride[0] * h);
 i420[1] = (uint8_t*)malloc((size_t)i420Stride[1] * h);
 i420[2] = (uint8_t*)malloc((size_t)i420Stride[2] * h);

 int toI420Res = sws_scale(rgbToI420Context, rgb, rgbStride, 0, h, i420, i420Stride);
 if (toI420Res < 0) {
 fprintf(stderr, "Conversion from RGB to I420 failed, %s.\n", av_make_error_string(_errorLog, ERROR_LEN, toI420Res));
 }

 printf("Converting I420 to RGB.\n");

 uint8_t* rgbOut[3];
 int rgbOutStride[3];

 rgbOutStride[0] = w * 3;
 rgbOut[0] = (uint8_t*)malloc((size_t)rgbOutStride[0] * h);

 int toRgbRes = sws_scale(i420ToRgbContext, i420, i420Stride, 0, h, rgbOut, rgbOutStride);
 if (toRgbRes < 0) {
 fprintf(stderr, "Conversion from RGB to I420 failed, %s.\n", av_make_error_string(_errorLog, ERROR_LEN, toRgbRes));
 }

 CreateBitmapFile(L"test-output.bmp", WIDTH, HEIGHT, 24, rgbOut, WIDTH * HEIGHT * 3);

 free(rgbOut[0]);

 for (int i = 0; i < 3; i++) {
 free(i420[i]);
 }

 sws_freeContext(rgbToI420Context);
 sws_freeContext(i420ToRgbContext);

 return 0;
}

/**
* Creates a bitmap file and writes to disk.
* @param[in] fileName: the path to save the file at.
* @param[in] width: the width of the bitmap.
* @param[in] height: the height of the bitmap.
* @param[in] bitsPerPixel: colour depth of the bitmap pixels (typically 24 or 32).
* @param[in] bitmapData: a pointer to the bytes containing the bitmap data.
* @param[in] bitmapDataLength: the number of pixels in the bitmap.
*/
void CreateBitmapFile(LPCWSTR fileName, long width, long height, WORD bitsPerPixel, BYTE* bitmapData, DWORD bitmapDataLength)
{
 HANDLE file;
 BITMAPFILEHEADER fileHeader;
 BITMAPINFOHEADER fileInfo;
 DWORD writePosn = 0;

 file = CreateFile(fileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); //Sets up the new bmp to be written to

 fileHeader.bfType = 19778; //Sets our type to BM or bmp
 fileHeader.bfSize = sizeof(fileHeader.bfOffBits) + sizeof(RGBTRIPLE); //Sets the size equal to the size of the header struct
 fileHeader.bfReserved1 = 0; //sets the reserves to 0
 fileHeader.bfReserved2 = 0;
 fileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER); //Sets offbits equal to the size of file and info header
 fileInfo.biSize = sizeof(BITMAPINFOHEADER);
 fileInfo.biWidth = width;
 fileInfo.biHeight = height;
 fileInfo.biPlanes = 1;
 fileInfo.biBitCount = bitsPerPixel;
 fileInfo.biCompression = BI_RGB;
 fileInfo.biSizeImage = width * height * (bitsPerPixel / 8);
 fileInfo.biXPelsPerMeter = 2400;
 fileInfo.biYPelsPerMeter = 2400;
 fileInfo.biClrImportant = 0;
 fileInfo.biClrUsed = 0;

 WriteFile(file, &fileHeader, sizeof(fileHeader), &writePosn, NULL);

 WriteFile(file, &fileInfo, sizeof(fileInfo), &writePosn, NULL);

 WriteFile(file, bitmapData, bitmapDataLength, &writePosn, NULL);

 CloseHandle(file);
}


The source bitmap is :




The output bmp after the two conversions is :




Syndiquer tout le site
