libav (or libav*) is the collective name of the FFmpeg libraries: libavcodec, libavformat, libavfilter, libavutil, etc. The name has also been appropriated by the Libav project–a fork of FFmpeg.
Questions tagged [libav]
591 questions
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Audio decoding using ffms2(ffmegsource)
I'm using ffms2(ffmpegsource) a wrapper around libav to get video and audio frame from a file.
Video decoding is working fine. However I'm facing some issues with audio decoding.
FFMS2 provide a simple function FFMS_GetAudio(FFMS_AudioSource *A,…
praks411
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Can the frame size be cropped during decoding using libavcodec?
I've followed Dranger's tutorial for displaying video using libav and FFMPEG. http://dranger.com/ffmpeg/
avcodec_decode_video2 seems to be the slowest part of the video decoding process. I will occasionally have two videos decoding simultaneously…
James491
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Ffmpeg-Build: Error during build
I am building ffmpeg and stuck in an unusual spot. Inside libavutil we have float_dsp.h and float_dsp.c files. Inside these file there is a declaration of a methond which is:
void (*butterflies_float)(float *av_restrict v1, float *av_restrict v2,…
Talha Malik
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avformat_write_header produces invalid header (resulting MPG broken)
I am rendering a video file from input pictures that come from a 3D engine at runtime (I don't pass an actual picture file, just RGB memory).
This works perfectly when outputting MP4 using CODEC_ID_H264 as video codec.
But when I want to create an…
TheSHEEEP
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ffmpeg or libav to create audio recording webapp?
Is it possible to create a web application which can record audio or video using ffmpeg or libav?
Or are these only for creating desktop aplications for encoding, decoding, recording audio/video?
user1725127
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Using std::vector instead of fread() in libav encode/decode example
I am attempting to take the api-example.c which reads in a file using fread to instead use memcpy (or the like) as I have loaded the file I wish to decode & encode into a different codec in a std::vector. (Due to I read it to memory from a…
brad_c6
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LibAV Mpeg_TS stream doesn't appear to contain I frames
I'm trying to take a YUV 420 stream, convert it to MPEG2 and send it via UDP as a transmport stream.
The conversion appears to work correctly, by saving the output I can create a playable MPEG. When viewing the transmitted packets in wireshark I am…
dougie
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How to decode Full Rate GSM Audio file?
I have to decode a full rate gsm audio file. Full Rate GSM Audio file is decoded using libgsm. I have used MSVC++ with windows nightly builds of ffmpeg and libav but unable to decode file correctly. Can anyone tell me the reason? I have tried…
Salman
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Error using libavcodec with linux in C/C++
The problem: AVFormatContext::nb_streams has too larve value.
My C++ code (error handling, includes etc. omited to reduce the listing):
void printA(AVFormatContext* _a)
{
std::cout << "duration " << (unsigned long)_a->duration << "\n";
std::cout…
pavelkolodin
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3 answers
Convert .264 to .ts using ffmpeg library
I'm currently working on converting h.264 elementary stream (file with postfiix .264) to transport stream (file with postfix .ts). I have finished the conversion successfully using ffmpeg command line "ffmpeg -i in.264 -an -vcodec copy -f mpegts…
summerlismile
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libav: Filling AVFrame with RGB24 sample data?
I am trying to fill sample data for a AVFrame initialized with RGB24 format.
I use following code snippet to populate RGB data.
But in the encoded video,I can only see grayscale strip covering only 1/3 of the videoframe.
This code snippet suppose to…
Ashika Umanga Umagiliya
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Using libav, how to force RTSP stream over TCP?
By using ffmpeg or ffplay you may specify "-rtsp_transport tcp" switch to force the rtsp stream be opened via tcp. In programming, I'm using libav to open the rtsp stream with the following code:
AVDictionary *options = NULL;
av_dict_set(&options,…
hamidi
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How to increase the compression ratio of a JPEG2000 file with "avenc_jpeg2000" GStreamer encoder?
I'm using the plugin avenc_jpeg2000, from gst-libav module, combined with videotestsrc and filesink plugins for encoding a raw picture to a JPEG2000 picture:
gst-launch-1.0 videotestsrc num-buffers=1 ! avenc_jpeg2000 ! filesink…
qfr.bertin.group
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Could someone please explain this filter graph?
https://www.ffmpeg.org/doxygen/trunk/filtering_video_8c-example.html
filter_graph = avfilter_graph_alloc();
// ...
const AVFilter *buffersrc = avfilter_get_by_name("buffer");
const AVFilter *buffersink =…
Wynell
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2 answers
AVFrame buf size calculation
I am having trouble encoding a video with the ffmpeg libraries as i am getting segfaults and/or out of bound memory writing when i am writing raw video data to an AVFrame. I therefore just wanted to ask if one of my assumptions was right.
Am i right…
Elias Wagnerberger
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