Newest 'ffmpeg' Questions - Stack Overflow
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av_log() function in ffmpeg to output to a file
11 mars, par TilakVarisettyI am logging time-stamps, and frames using
av_log()to the console. Unfortunately, the console does not pipe to a file.Is there a way to add function or other options to log to the file directly, instead of the console?
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Linker error by trying example program with ffmpeg
11 mars, par ChrisI think this might be a stupid question and I'm just blind but that thing is driving me nuts for hours now. I downloaded ffmpeg and build it. Now I want to try the thing out in a program but I can't setup cmake to link ffmpeg properly and have no idea what is wrong.
The linker always tells me this:
christoph@christoph-ThinkPad-T490:~/develop/ffmpg_example/build$ make [ 50%] Linking CXX executable test CMakeFiles/test.dir/main.cxx.o: In function `main': main.cxx:(.text+0x180): undefined reference to `av_register_all()' main.cxx:(.text+0x1a7): undefined reference to `avformat_open_input(AVFormatContext**, char const*, AVInputFormat*, AVDictionary**)' main.cxx:(.text+0x1ce): undefined reference to `avformat_find_stream_info(AVFormatContext*, AVDictionary**)' main.cxx:(.text+0x206): undefined reference to `av_dump_format(AVFormatContext*, int, char const*, int)' main.cxx:(.text+0x2bb): undefined reference to `avcodec_find_decoder(AVCodecID)' main.cxx:(.text+0x2fc): undefined reference to `avcodec_alloc_context3(AVCodec const*)' main.cxx:(.text+0x316): undefined reference to `avcodec_copy_context(AVCodecContext*, AVCodecContext const*)' main.cxx:(.text+0x361): undefined reference to `avcodec_open2(AVCodecContext*, AVCodec const*, AVDictionary**)' main.cxx:(.text+0x377): undefined reference to `av_frame_alloc()' main.cxx:(.text+0x383): undefined reference to `av_frame_alloc()' main.cxx:(.text+0x3ba): undefined reference to `avpicture_get_size(AVPixelFormat, int, int)' main.cxx:(.text+0x3d0): undefined reference to `av_malloc(unsigned long)' main.cxx:(.text+0x3ff): undefined reference to `avpicture_fill(AVPicture*, unsigned char const*, AVPixelFormat, int, int)' main.cxx:(.text+0x43d): undefined reference to `sws_getContext(int, int, AVPixelFormat, int, int, AVPixelFormat, int, SwsFilter*, SwsFilter*, double const*)' main.cxx:(.text+0x465): undefined reference to `av_read_frame(AVFormatContext*, AVPacket*)' main.cxx:(.text+0x49f): undefined reference to `avcodec_decode_video2(AVCodecContext*, AVFrame*, int*, AVPacket const*)' main.cxx:(.text+0x4fd): undefined reference to `sws_scale(SwsContext*, unsigned char const* const*, int const*, int, int, unsigned char* const*, int const*)' main.cxx:(.text+0x545): undefined reference to `av_free_packet(AVPacket*)' main.cxx:(.text+0x556): undefined reference to `av_free(void*)' main.cxx:(.text+0x565): undefined reference to `av_frame_free(AVFrame**)' main.cxx:(.text+0x574): undefined reference to `av_frame_free(AVFrame**)' main.cxx:(.text+0x580): undefined reference to `avcodec_close(AVCodecContext*)' main.cxx:(.text+0x58f): undefined reference to `avcodec_close(AVCodecContext*)' main.cxx:(.text+0x59e): undefined reference to `avformat_close_input(AVFormatContext**)' collect2: error: ld returned 1 exit status CMakeFiles/test.dir/build.make:87: recipe for target 'test' failed make[2]: *** [test] Error 1 CMakeFiles/Makefile2:75: recipe for target 'CMakeFiles/test.dir/all' failed make[1]: *** [CMakeFiles/test.dir/all] Error 2 Makefile:83: recipe for target 'all' failed make: *** [all] Error 2The cmake list looks like this:
cmake_minimum_required(VERSION 3.16) project(ffmpeg_test) add_library(avformat STATIC IMPORTED) set_target_properties(avformat PROPERTIES IMPORTED_LOCATION /home/christoph/develop/FFmpeg/build/lib/libavformat.a ) add_library(avcodec STATIC IMPORTED) set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION /home/christoph/develop/FFmpeg/build/lib/libavcodec.a ) add_library(swscale STATIC IMPORTED) set_target_properties(swscale PROPERTIES IMPORTED_LOCATION /home/christoph/develop/FFmpeg/build/lib/libswscale.a ) add_library(avutil STATIC IMPORTED) set_target_properties(avutil PROPERTIES IMPORTED_LOCATION /home/christoph/develop/FFmpeg/build/lib/libavutil.a ) add_executable(test main.cxx) target_link_libraries(test PRIVATE /home/christoph/develop/FFmpeg/build/lib/libavformat.a avcodec swscale avutil ) target_include_directories(test PRIVATE /home/christoph/develop/FFmpeg/build/include)And here are the ffmpeg libs:
christoph@christoph-ThinkPad-T490:~/develop/FFmpeg/build/lib$ ll total 277840 drwxr-xr-x 3 christoph christoph 4096 Dez 7 23:59 ./ drwxr-xr-x 17 christoph christoph 4096 Dez 7 23:59 ../ -rw-r--r-- 1 christoph christoph 173479270 Dez 7 23:59 libavcodec.a -rw-r--r-- 1 christoph christoph 2174910 Dez 7 23:59 libavdevice.a -rw-r--r-- 1 christoph christoph 37992438 Dez 7 23:59 libavfilter.a -rw-r--r-- 1 christoph christoph 59222040 Dez 7 23:59 libavformat.a -rw-r--r-- 1 christoph christoph 4759514 Dez 7 23:59 libavutil.a -rw-r--r-- 1 christoph christoph 695698 Dez 7 23:59 libswresample.a -rw-r--r-- 1 christoph christoph 6164398 Dez 7 23:59 libswscale.a drwxr-xr-x 2 christoph christoph 4096 Dez 7 23:59 pkgconfig/And this is the example code:
#include #includeavcodec.h> #include avformat.h> #include swscale.h> // compatibility with newer API #if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(55,28,1) #define av_frame_alloc avcodec_alloc_frame #define av_frame_free avcodec_free_frame #endif void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) { FILE *pFile; char szFilename[32]; int y; // Open file sprintf(szFilename, "frame%d.ppm", iFrame); pFile=fopen(szFilename, "wb"); if(pFile==NULL) return; // Write header fprintf(pFile, "P6\n%d %d\n255\n", width, height); // Write pixel data for(y=0; ydata[0]+y*pFrame->linesize[0], 1, width*3, pFile); // Close file fclose(pFile); } int main(int argc, char *argv[]) { // Initalizing these to NULL prevents segfaults! AVFormatContext *pFormatCtx = NULL; int i, videoStream; AVCodecContext *pCodecCtxOrig = NULL; AVCodecContext *pCodecCtx = NULL; AVCodec *pCodec = NULL; AVFrame *pFrame = NULL; AVFrame *pFrameRGB = NULL; AVPacket packet; int frameFinished; int numBytes; uint8_t *buffer = NULL; struct SwsContext *sws_ctx = NULL; if(argc < 2) { printf("Please provide a movie file\n"); return -1; } // Register all formats and codecs av_register_all(); // Open video file if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0) return -1; // Couldn't open file // Retrieve stream information if(avformat_find_stream_info(pFormatCtx, NULL)<0) return -1; // Couldn't find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, argv[1], 0); // Find the first video stream videoStream=-1; for(i=0; inb_streams; i++) if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) { videoStream=i; break; } if(videoStream==-1) return -1; // Didn't find a video stream // Get a pointer to the codec context for the video stream pCodecCtxOrig=pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec=avcodec_find_decoder(pCodecCtxOrig->codec_id); if(pCodec==NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // Copy context pCodecCtx = avcodec_alloc_context3(pCodec); if(avcodec_copy_context(pCodecCtx, pCodecCtxOrig) != 0) { fprintf(stderr, "Couldn't copy codec context"); return -1; // Error copying codec context } // Open codec if(avcodec_open2(pCodecCtx, pCodec, NULL)<0) return -1; // Could not open codec // Allocate video frame pFrame=av_frame_alloc(); // Allocate an AVFrame structure pFrameRGB=av_frame_alloc(); if(pFrameRGB==NULL) return -1; // Determine required buffer size and allocate buffer numBytes=avpicture_get_size(AV_PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height); buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t)); // Assign appropriate parts of buffer to image planes in pFrameRGB // Note that pFrameRGB is an AVFrame, but AVFrame is a superset // of AVPicture avpicture_fill((AVPicture *)pFrameRGB, buffer, AV_PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height); // initialize SWS context for software scaling sws_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_RGB24, SWS_BILINEAR, NULL, NULL, NULL ); // Read frames and save first five frames to disk i=0; while(av_read_frame(pFormatCtx, &packet)>=0) { // Is this a packet from the video stream? if(packet.stream_index==videoStream) { // Decode video frame avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); // Did we get a video frame? if(frameFinished) { // Convert the image from its native format to RGB sws_scale(sws_ctx, (uint8_t const * const *)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize); // Save the frame to disk if(++i<=5) SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i); } } // Free the packet that was allocated by av_read_frame av_free_packet(&packet); } // Free the RGB image av_free(buffer); av_frame_free(&pFrameRGB); // Free the YUV frame av_frame_free(&pFrame); // Close the codecs avcodec_close(pCodecCtx); avcodec_close(pCodecCtxOrig); // Close the video file avformat_close_input(&pFormatCtx); return 0; } -
FFMPEG compile with x264 support for Android
10 mars, par PecanaI am trying to build ffmpeg extensions for media3 (ExoPlayer) for Android
https://github.com/androidx/media/tree/release/libraries/decoder_ffmpeg
Using the default settings everything is fine but if I try to add support to libx264 the build failed. I compiled x264 for Android locally and it worked so the .so file for arm64 is present, I added it to the pkg-config with :
export PKG_CONFIG_PATH=/build/x264/arm64/lib/pkgconfig:$PKG_CONFIG_PATHbut when I try to build ffmpeg with the following command it fails :
./configure \ --prefix=/build/ffmpeg \ --enable-gpl \ --enable-libx264 \ --enable-static \ --enable-pic \ --arch=arm64 \ --target-os=android \ --cross-prefix=$TOOLCHAIN/bin/aarch64-linux-android21- \ --sysroot=$SYSROOTError : ERROR: x264 not found using pkg-config
But it is not due to pkg-config as the command:
pkg-config --cflags --libs x264reports : -DX264_API_IMPORTS -I/build/x264/arm64/include -L/build/x264/arm64/lib -lx264
Any idea on how to fix it ?
Thank you :-)
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How to seek one frame forward in ffmpeg [closed]
10 mars, par Summiti want to seek one frame forward when i call this function but it gets stuck on the first frame seeked and does not move forward.
void seekFrameUp() { if (!fmt_ctx || video_stream_index == -1) return; AVRational frame_rate = fmt_ctx->streams[video_stream_index]->r_frame_rate; if (frame_rate.num == 0) return; // Avoid division by zero // Compute frame duration in AV_TIME_BASE_Q int64_t frame_duration = av_rescale_q(1, av_make_q(frame_rate.den, frame_rate.num), AV_TIME_BASE_Q); int64_t next_pts = requestedTimestamp + frame_duration; qDebug() << "Seeking forward: " << next_pts << " (Current PTS: " << requestedTimestamp << ", Frame Duration: " << frame_duration << ")"; requestFrameAt(next_pts); // Update the requested timestamp after seeking requestedTimestamp = next_pts; } void requestFrameAt(int64_t timestamp) { { std::lock_guard lock(mtx); decoding = true; // Ensure the thread keeps decoding when needed } cv.notify_one(); } void decodeLoop() { while (!stopThread) { std::unique_lock lock(mtx); cv.wait(lock, [this] { return decoding || stopThread; }); if (stopThread) break; // Avoid redundant seeking if (requestedTimestamp == lastRequestedTimestamp) { decoding = false; continue; } lastRequestedTimestamp.store(requestedTimestamp.load()); int64_t target_pts = av_rescale_q(requestedTimestamp, AV_TIME_BASE_Q, fmt_ctx->streams[video_stream_index]->time_base); target_pts = FFMAX(target_pts, 0); // Ensure it's not negative if (av_seek_frame(fmt_ctx, video_stream_index, target_pts, AVSEEK_FLAG_ANY) >= 0) { avcodec_flush_buffers(codec_ctx); // Clear old frames from the decoder qDebug() << "Seek successful to PTS:" << target_pts; } else { qDebug() << "Seeking failed!"; decoding = false; continue; } lock.unlock(); // Keep decoding until we receive a valid frame bool frameDecoded = false; while (av_read_frame(fmt_ctx, pkt) >= 0) { if (pkt->stream_index == video_stream_index) { if (avcodec_send_packet(codec_ctx, pkt) == 0) { while (avcodec_receive_frame(codec_ctx, frame) == 0) { qDebug() << "FRAME DECODED ++++++++++++ PTS:" << frame->pts; if (frame->pts != AV_NOPTS_VALUE) { // Rescale PTS to AV_TIME_BASE_Q int64_t pts_in_correct_base = av_rescale_q(frame->pts, fmt_ctx->streams[video_stream_index]->time_base, AV_TIME_BASE_Q); // Ensure we don’t reset to 0 incorrectly if (pts_in_correct_base > 0) { current_pts.store(pts_in_correct_base); qDebug() << "Updated current_pts to:" << current_pts.load(); } else { qDebug() << "Warning: Decoded frame has PTS <= 0, keeping last valid PTS."; } } else { qDebug() << "Invalid frame->pts (AV_NOPTS_VALUE)"; } QImage img = convertFrameToImage(frame); emit frameDecodedSignal(img); frameDecoded = true; break; // Exit after the first valid frame } if (frameDecoded) { decoding = (requestedTimestamp != lastRequestedTimestamp); break; } } } av_packet_unref(pkt); } } } -
How to Use SVG Image Files Directly in FFmpeg ? [closed]
10 mars, par Pubg MobileI generated a bar chart race using the Flourish Studio website and captured the frames as a PDF sequence using a Python Playwright script. Then, I converted all the PDF files into SVG format using the following Python script, because SVG is the only image format that maintains quality without loss when zoomed in:
import os import subprocess import multiprocessing # Define paths pdf2svg_path = r"E:\Desktop\dist-64bits\pdf2svg.exe" # Full path to pdf2svg.exe input_dir = r"E:\Desktop\New folder (4)\New folder" output_dir = r"E:\Desktop\New folder (4)\New folder (2)" # Ensure output directory exists os.makedirs(output_dir, exist_ok=True) def convert_pdf_to_svg(pdf_file): """ Convert a single PDF file to SVG. """ input_pdf = os.path.join(input_dir, pdf_file) output_svg = os.path.join(output_dir, os.path.splitext(pdf_file)[0] + ".svg") try: subprocess.run([pdf2svg_path, input_pdf, output_svg], check=True) print(f"Converted: {pdf_file} -> {output_svg}") except FileNotFoundError: print(f"Error: Could not find {pdf2svg_path}. Make sure the path is correct.") except subprocess.CalledProcessError: print(f"Error: Conversion failed for {pdf_file}") if __name__ == "__main__": # Get list of PDF files in input directory pdf_files = [f for f in os.listdir(input_dir) if f.lower().endswith(".pdf")] # Use multiprocessing to speed up conversion with multiprocessing.Pool(processes=multiprocessing.cpu_count()) as pool: pool.map(convert_pdf_to_svg, pdf_files) print("All conversions completed!")Problem:
Now, I want to use these SVG images in FFmpeg to create a high-quality video file. However, FFmpeg does not support SVG files directly, and I have read that I must convert SVG files into PNG before using them in FFmpeg. The problem is that PNG images reduce quality, especially when zooming in, which is why I want to avoid converting to PNG.
Is there any way to use SVG files directly in FFmpeg or another method to convert them into a high-quality video while maintaining full resolution? Any ideas or suggestions would be greatly appreciated!
