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2
votes
1
answer
135
views
Libav* encoding to FLAC results in MD5 Signature Mismatch
I am trying to learn how to use the FFmpeg libav* libraries but have encountered an issue when encoding to FLAC audio.
Running FFmpeg 5.1.7
I have copied the transcoding.c example from https://www....
2
votes
0
answers
112
views
How can I dynamically update metadata in audio output with libav so that updates appear in MPV?
My ultimate goal is to proxy an internet radio station and programmatically add metadata to it during the stream that can be displayed and updated in MPV, the media player playing the audio.
The ...
0
votes
0
answers
81
views
How to reinitialize AVCodec with updated AVCodecContext on fly
There is a question about an old (0.7) version of the FFMPEG(LibAV) library, including to my project as
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/...
0
votes
1
answer
89
views
some codecs (ie. libx264) cannot be reused after draining
After draining an encoder (by sending it a null frame and then receiving packets until EOF) it enters draining mode after which avcodec_send_frame will fail, returning EOF. You're supposed to call ...
2
votes
1
answer
130
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LibAV: converting PTS to frame number
I am developing an mp4 demuxer with LibAV. I need a helper function which converts PTS to frame numbers. I came up with the following code which works. But I am not sure how correct it is in the LibAV ...
-2
votes
1
answer
59
views
avformat_write_header return error code when trying to write video with G711U audio avi file
I'm trying to make an avi file from a video/audio stream. When audio is AAC it works fine. But I cannot pack G711U audio.
av_register_all();
avcodec_register_all();
av_log_set_callback(nullptr);
...
0
votes
0
answers
127
views
Problems using FFmpeg / libavfilter for adding overlay to grabbed frames
On Windows with latest FFmpeg / libav (full build, non-free) a C/C++ app reads YUV420P frames from a frame grabber card.
A bitmap (BGR24) overlay image from file should be drawn on every frame for the ...
0
votes
0
answers
60
views
How to feed frames one by one and grab decoded frames using LibAV?
I am integrating a third party system where I send a TCP packet to ask e.g. 5 frames from a live CCTV camera stream, and it sends those 5 frames one by one. Each package is h264 encoded frame, wrapped ...
1
vote
0
answers
312
views
How can I extract PGS/SUP subtitles from mkv container via libav
Trying to write a C code that does the equivalent of the following ffmpeg command:
ffmpeg -i video.mkv -map 0:"$STREAM_INDEX" -c:s copy subtitles.sup
I have managed to read the media ...
3
votes
0
answers
169
views
How to render AVFrames more efficiently?
I have currently got the frame on the GPU and can render it smoothly. I have a decoding thread and a rendering thread. The decoding thread puts the decoded pointer to the GPU into a List, and the ...
1
vote
3
answers
102
views
Inheriting Structs in C++
I am working with the LibAV library, converting it from C to C++ (and moving to an object oriented style).
This library has structs to hold data, which need to be created using specific allocation ...
2
votes
0
answers
187
views
ffmpeg: libavfilter API av_buffersink_get_frame returns alway EAGAIN
I want to resize an image with libavfilter C API through zscale filter and libplacebo filter but no matter how I call av_buffersink_get_frame, it always returns EAGAIN and no data is filled in the ...
3
votes
0
answers
215
views
Producing streamable video from screen using gdigrab and ffmpeg.autogen libav wrapper
I'm working on creating a class that captures the screen, encodes it using H.264, and outputs it in a streamable format to a pipe. For this, I'm using the ffmpeg.autogen version 5.1.2.3 (It is a libav ...
0
votes
1
answer
143
views
Error encoding H.264 video with libav from frame grabber source
I am struggling since days with the actual issue. I did hours of internet search, ChatGPT sessions, code reviewing etc. but I don't get it working as expected.
Base: Windows 11 Pro x64, own LGPL build ...
2
votes
1
answer
228
views
FFmpeg does not detect bitstream filter parameter
I have tried to make a bitstream filter for FFmpeg that drops the nth keyframe for positive numbers and allows the first n keyframes and drops the rest for nonpositive numbers, called "datamosh&...