Re: [Libav-user] Scale filter converting to grayscale

[Philippe Gorley]

On 2018-04-30 03:44 PM, Carl Eugen Hoyos wrote:

2018-04-30 21:10 GMT+02:00, Philippe Gorley
:


It segfaults when writing the frame. I'm expecting a yuv420p frame


But you are asking the filter chain to output gray.


enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
if ((ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,


I guess I should've looked more carefully. Thank you.




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Cheers,

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Philippe Gorley
Free Software Consultant | Montréal, Qc
Savoir-faire Linux
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Re: [Libav-user] Scale filter converting to grayscale

[Carl Eugen Hoyos]

2018-04-30 21:10 GMT+02:00, Philippe Gorley
:

> It segfaults when writing the frame. I'm expecting a yuv420p frame

But you are asking the filter chain to output gray.

> enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
>if ((ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,

> Confidentiality Message: This communication (including any files
> transmitted with it) is intended solely for the person or entity to
> whom it is addressed, and may contain confidential or privileged
> information.

Please remove this from mails sent to a public mailing list.

Carl Eugen
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[Libav-user] Scale filter converting to grayscale

[Philippe Gorley]

Hi,

I'm having trouble getting filters to work correctly. It creates dummy 
YUV frames, scales them using libavfilter, and saves the raw data to 
disk (heavily based on filtering_video.c). The end goal is to use 
libavfilter instead of implementing such things ourselves.


It segfaults when writing the frame. I'm expecting a yuv420p frame, but 
the filtered frame is in grayscale (AV_PIX_FMT_GRAY8), even though I 
specify yuv420p in the filter string (scale=w=200:h=100:dst_format=0).


Here is the code: https://pastebin.com/rNegZcng
I'm on FFmpeg master (commit cae6f806a6367c7760ab6ed059d343d4a8eebd56).

And here are the logs I'm getting:
detected 4 logical cores
[in @ 0x1e41200] Setting 'video_size' to value '320x240'
[in @ 0x1e41200] Setting 'pix_fmt' to value '0'
[in @ 0x1e41200] Setting 'time_base' to value '1/1'
[in @ 0x1e41200] Setting 'pixel_aspect' to value '1/1'
[in @ 0x1e41200] w:320 h:240 pixfmt:yuv420p tb:1/1 fr:0/1 sar:1/1 sws_param:
[Parsed_scale_0 @ 0x1e42280] Setting 'w' to value '200'
[Parsed_scale_0 @ 0x1e42280] Setting 'h' to value '100'
[Parsed_scale_0 @ 0x1e42280] Setting 'dst_format' to value '0'
[Parsed_scale_0 @ 0x1e42280] w:200 h:100 flags:'bilinear' interl:0
[AVFilterGraph @ 0x1e407c0] query_formats: 3 queried, 2 merged, 0 
already done, 0 delayed
[Parsed_scale_0 @ 0x1e42280] w:320 h:240 fmt:yuv420p sar:1/1 -> w:200 
h:100 fmt:gray sar:2/3 flags:0x2
[Parsed_scale_0 @ 0x1e42280] w:320 h:240 fmt:yuv420p sar:0/1 -> w:200 
h:100 fmt:gray sar:0/1 flags:0x2

[swscaler @ 0x1e42f80] bad dst image pointers
Frame scaled from 320x240 to 200x100
Segmentation fault

Backtrace:
#0  __mempcpy_sse2 () at ../sysdeps/x86_64/memcpy.S:196
#1  0x77364242 in _IO_new_file_xsputn (f=0x635430, data=0x0, 
n=0x64) at fileops.c:1319
#2  0x773597bb in __GI__IO_fwrite (buf=0x0, size=0x64, 
count=0x1, fp=0x635430) at iofwrite.c:39
#3  0x0040114b in save_yuv_frame (frame=0x604040, 
frame_number=0x0) at video_filter.c:52
#4  0x00401a4f in main (argc=0x1, argv=0x7fffda48) at 
video_filter.c:203


Any tips on what I'm doing wrong and why libavfilter is converting my 
frame to AV_PIX_FMT_GRAY8?


Cheers,

--
Philippe Gorley
Free Software Consultant | Montréal, Qc
Savoir-faire Linux

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Re: [Libav-user] Setting up ffmpeg avcodec wiht Qt Linux undefined reference

[Carl Eugen Hoyos]

2018-04-30 16:47 GMT+02:00, buff...@mailbox.org :

> im trying to get the example from
> https://www.ffmpeg.org/doxygen/trunk/decode_video_8c-example.html
> running.

Did you test the following?
$ make doc/examples/decode_video

Carl Eugen
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[Libav-user] Setting up ffmpeg avcodec wiht Qt Linux undefined reference

[buffgix]

Hi,

im trying to get the example from 
https://www.ffmpeg.org/doxygen/trunk/decode_video_8c-example.html running.

Im using Qt Creator (C++) with Widgets and compiled ffmpeg manually (Kubuntu 
18.04.0 64 bit).

Unfortunately im getting "undefined reference" errors for every avcodec 
function (e.g. avcodec_send_packet 
https://www.ffmpeg.org/doxygen/trunk/group__lavc__decoding.html#ga58bc4bf1e0ac59e27362597e467efff3
 (dec_ctx, pkt) ...)

I added headers and libs in the qmake file with:

INCLUDEPATH += /home/user/ffmpeg_build/include

LIBS += /home/user/ffmpeg_build/lib/libavcodec.a


I have tried:

extern "C" {
#include 
}

without success.


I attached a file with the "undefined reference" errors.


Kind Regards



undefined_ref_log
Description: Binary data
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