Hi.
The implementation of 'avdevice_capabilities_create'(
https://ffmpeg.org/doxygen/trunk/avdevice_8c_source.html#l00143) starts
with the following lines:
1int ret;
2av_assert0(s && caps);
3av_assert0(s->iformat || s->oformat);
4if ((s->oformat &&
Hi.
Sorry, I think I got it wrong in my previous reply:
> I think there is no way to retrieve the information using the FFMPEG API.
There is this:
https://ffmpeg.org/doxygen/trunk/structAVDeviceCapabilitiesQuery.html
Quoting the docs:
> Following API allows user to probe device capabilities
Hi.
> Is it because of NVIDIA GPUs have concurrent session limitation?
There is a session limitation for encoding for sure, but I think there is
no such thing for decoding:
https://developer.nvidia.com/video-encode-decode-gpu-support-matrix
> By the way, I don't understand where these messages
Hi.
I think this is what you need:
https://www.ffmpeg.org/legal.html
Regards.
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Hi.
I faced a similar problem:
http://ffmpeg.org/pipermail/libav-user/2018-October/011413.html
I think there is no way to retrieve the information using the FFMPEG API.
As a workaround you can use a log call back to store the printed formats
info and later parse that information.
Regards.
Hi Ethin.
> The interface to libav also looks unnecessarily complicated, or is that
just me.
When learning libav, at first, I felt the same way. The interface is
complicated by not unnecessarily.
Concerning the rest of your questions: too vague to give a definitive
answer.
For a conferencing
Hi.
I have a HLS input and I want to be able to get value of
the #EXT-X-TARGETDURATION tag(the segments target duration) of the .m3u8
file. Is that possible? Can that information be recovered from the
AVFormatContext struct?
The reason why I need the target duration of the hls segments is the
Hi Wodzu.
>From the ffmeg docs about avformat_find_stream_info():
- Read packets of a media file to get stream information.
- The logical file position is not changed by this function; examined
packets may be buffered for later processing.
* Read packets of a media file to get stream
Hi Carl,
> But the setpts filter is changing the framerate to 60 fps, no?
I am pretty sure it does not, it changes the timebase in use. In a stream
with 1/30 tb and pts values [0,1,2,3,4,5], using a 1/60 tb those pts values
would change to [0,2,4,6,8,10].
> WMP only supports yuv420p, this is
Hi Carl,
> In this example, it looks as if the input already has 60fps.
The inputs is 30fps, set by the '-r' flag. Maybe the settb filter is
throwing you off, but it only changes the timebase to 1/60, the framerate
is kept to 30/1.
> Your original email gave the impression that vstack somehow
Hi Carl.
> How can I reproduce this (major?) issue with ffmpeg (the application)?
.\ffmpeg.exe -y -loop 1 -r 30 -t 5 -i .\frame.png -filter_complex
"[0]settb=expr=1/60[tb];[tb]split[s0][s1];[s1]setpts=PTS+1[offset];[s0][offset]vstack[out]"
-map [out] -c:v h264 -vsync 0 -f mp4 out.mp4
Here is
Hi
I forgot to speak about the timebases in use, and those are important in
this case.
For my two inputs, after decoding, my AVCodecContexts have the following
framerates and timebases:
in0 => 30/1, 1/60
in1 => 359/12, 6/359 // Well this is not exactly 30fps, but close.
The common selected
Hi.
In my program I have the following filter:
"
[in0]format=pix_fmts=yuv420p,scale=-1:540[s0];
[in1]format=pix_fmts=yuv420p,scale=-1:540[s1];
[s0][s1]vstack[stacked];
[stacked]pad=1920:1080:(ow-iw)/2:0[out0]
"
My problem comes from the 'vstack' filter. The stack filters assign the
same
Hi Yury
On Thu, Oct 25, 2018 at 11:18 AM Yurii Monakov wrote:
> Resampling can introduce additional samples in the output (because
> out_samples is rounded).
> You should keep track of input time and output time to calculate number of
> output samples.
>
> Yurii
>
I am not sure if that is true
Hi Yang,
> While I'm using av_read_frame to extract frames from some rtsp stream
from IP cameras, the dts/pts of the next frame occasionally will be smaller
than the previous frames.
Currently I am facing the same problem.
> Is it a bug of libav or a P frame or maybe there's a bug in the IP
Hi Anton,
Recently I built ffmpeg with VC 2017 and had no problems.
I had to use the following flags with the configure script.
--arch=x86_64 \
--target-os=win64 \
--toolchain=msvc
Maybe you are missing the --arch, hope this helps you.
Hi.
The different devices ffmpeg supports have different options, I am
interested in the 'list_formats' of the decklink devices. Using the
ffmpeg.exe tool the following command:
ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro'
prints the formats that can be used with the device.
I
Hi.
I am looking into encoding once but writing to multiple files with
different formats.
For some formats the encoder must be configured with the
AV_CODEC_FLAG_GLOBAL_HEADER flag active, like this:
if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
enc_ctx->flags |=
Hi.
I am capturing video+audio of an IP camera(RTSP), transcoding it and saving
it to file.
The input looks like this:
Input #0, rtsp, from 'rtsp://10.1.1.22/?line=1=1_line=1':
Metadata:
title : LIVE VIEW
Duration: N/A, start: -0.001000, bitrate: N/A
Stream #0:0: Video:
Hi
I am trying to implement my first video filter. Now I am looking at the
following example:
https://www.ffmpeg.org/doxygen/trunk/filtering_video_8c-example.html
In the function:
79static int init_filters(const char *filters_descr)
we have this:
87AVRational time_base =
Hi,
I am writing(C++) a simple transcoding program. At first I did not
understand the concept of a timebase and how to work with it, until I found
this stackoverflow response:
https://stackoverflow.com/a/40278283/3022945
The response from the above link can be summarized as:
- Copy the
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