Re: [Libav-user] Fast parsing of H.264 video stream using libavcodec

[Gonzalo]

El 20/07/16 a las 18:58, Puneet Kapoor escribió:


If you could share some examples of multi-threaded libav user code, it 
would be helpful.


Thanks

Google for "dranger ffmpeg".  The original page is a tutorial page, but 
it is a tad out of date.  Some other repositories contain updated code.


Some demuxers may support multithreaded operation, albeit for most 
operations you gain little.  For that, you can use:


  AVDictionary* info = NULL;
  av_dict_set(, "threads", "auto", 0);

  avcodec_open2( video_ctx, video_codec,  );

--
Gonzalo Garramuño
ggarr...@gmail.com

___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

Re: [Libav-user] Fast parsing of H.264 video stream using libavcodec

[Puneet Kapoor]

I am new to H264 decoding and using this library, so pardon me if my
questions seem too naive.

Isn't the libav function  avcodec_decode_video2() internally multi-threaded
to be able to use multiple cores itself? Do we need to enable it somehow ?

If you could share some examples of multi-threaded libav user code, it
would be helpful.

Thanks
On Jul 21, 2016 3:14 AM, "Gonzalo"  wrote:

>
>
> El 20/07/16 a las 17:46, Puneet Kapoor escribió:
>
>>
>> By making it multithreaded ?
>>
>> Yes.
>
> --
> Gonzalo Garramuño
> ggarr...@gmail.com
>
> ___
> Libav-user mailing list
> Libav-user@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
>
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

Re: [Libav-user] Fast parsing of H.264 video stream using libavcodec

[Gonzalo]

El 20/07/16 a las 17:46, Puneet Kapoor escribió:


By making it multithreaded ?


Yes.

--
Gonzalo Garramuño
ggarr...@gmail.com

___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

[Libav-user] Fast parsing of H.264 video stream using libavcodec

[Puneet Kapoor]

Hi,

I am using Libav* libraries to decode the frames from the byte stream data
I am receiving from another thread.

I have been able to successfully parse the byte stream and render video
correctly using the OpenCV API. *Basic flow in my code using libav is like:*
*init() { *
*avcodec_find_decoder(AV_CODEC_ID_H264) ;*
*avcodec_alloc_context3(codec);*

*avcodec_open2(codec_context, codec, NULL)*




*picture = av_frame_alloc();pictureBGR = av_frame_alloc();parser =
av_parser_init(AV_CODEC_ID_H264);codec_context->thread_count = 2; // tried
to increase threads}readFrame() {int len = av_parser_parse2(parser,
codec_context, , , [0],
buffer.size(), 0, 0, AV_NOPTS_VALUE); ...int len_dec =
avcodec_decode_video2(codec_context, picture, _picture, ); // takes
most time (~77%)...iResult = sws_scale(...)*
*}*

The problem I am facing is related to performance of my decoding code. My
program manages to do 10 frames per second (fps) for a 720p video. When I
save the same video stream as a file and use OpenCV code to parse it, it is
able to parse the same video at around 24 fps.

I did basic profiling of my code and found that most of the time is going
in decoding call "*avcodec_decode_video2()*" (~77% time) and SWS rescaling
call "*sws_scale()*" (~18% time).

I haven't profiled the OpenCV code, but one difference I noticed is that
OpenCV code uses multiple cores from *top* and *time* command
statistics(shared below). And, my code runs single threaded.
My question here is: How can I improve the performance of my code ? By
making it multithreaded ? Are there any library specific tweaks that can
help ?

*Time command statistics*
*For OpenCV code:*
real 0m17.496s
user 0m48.030s
sys 0m2.410s

*For My code using Libav library:*
real 0m39.478s
user 0m39.380s
sys 0m0.100s


Thanks
Puneet
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

Re: [Libav-user] ffmpeg command line for video rendered from set of image snapshots

[Josef Vosyka]

>> ffmpeg -start_number 1 -framerate 2 -i img_%d.jpg
>> -c:v h264 -profile:v baseline -r 25 -s 208:160 movie.mp4
>
> Complete, uncut console output missing.

Working syntax:

string img_mask = imagesRootPath + "/img_%7d.jpg";
cmd_str = string_format("ffmpeg -start_number 1 -framerate %d -i %s
-b:v 132k -r 25 %s", framerate, img_mask.c_str(), out.c_str());


> Generally, this mailing list is for questions using the
> libraries, ffmpeg-user is for questions regarding
> command line usage.

Sorry about that. Will use correct forum next time.
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

[Libav-user] decoding for stream 0 failed ?

[ssshukla26]

Hi,

I am implementing a custom decoder of qualcomm chipset into ffmpeg, have a
working linux application for the same. I am able to run decoder, but its
closing with aN error as show below.

Note: The output format is nv12 tiled, we have already added support for
nv12 tile to yuv420p conversion in libswscale. 
0001-NV12-Tile-pixel-format-support-added.patch

  

# *ffmpeg -f h264 -c:v h264_qhw -i no_mans_sky_1080p_10sec.h264 -pix_fmt
nv12_tiled -s 1920x1080 -r 30 out_1080p.yuv*
ffmpeg version N-80917-gc5096bc Copyright (c) 2000-2016 the FFmpeg
developers
  built with gcc 4.9.2 (crosstool-NG linaro-1.13.1-4.9-2014.09 - Linaro GCC
4.9-2014.09) 20140904 (prerelease)
  configuration: --prefix=comark_SBC_ffmpeg/ --enable-shared
--enable-nonfree --enable-pic --enable-gpl --enable-cross-compile
--cross-prefix=arm-linux-gnueabihf- --arch=arm --target-os=linux
--extra-cflags=-I../sdl/source/SDL-1.2.15/comark_SBC_SDL//include/SDL/
--extra-ldflags='-L../sdl/source/SDL-1.2.15/comark_SBC_SDL//lib/ -lSDL'
  libavutil  55. 28.100 / 55. 28.100
  libavcodec 57. 48.101 / 57. 48.101
  libavformat57. 41.100 / 57. 41.100
  libavdevice57.  0.102 / 57.  0.102
  libavfilter 6. 47.100 /  6. 47.100
  libswscale  4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc54.  0.100 / 54.  0.100
Initialized Params
@ 328 in init_params : width = 1920 & height = 1080
Initialized Decoder
@ 680 in vdec_set_buffer_requirement : Input Buffer mincount=1
maxcount=32
actualcount=3
,buffer_size=2097152
,alignment=2048
@ 703 in vdec_set_buffer_requirement : Output Buffer mincount=6
maxcount=32
actualcount=10
,buffer_size=3137536
,alignment=8192
@ 910 in vdec_alloc_h264_mv : Entered vdec_alloc_h264_mv act_width: 1920,
act_height: 1080, size: 5570560, alignment 8192
Start Decoder
Buffers freed for reconfiguration
@ 910 in vdec_alloc_h264_mv : Entered vdec_alloc_h264_mv act_width: 1920,
act_height: 1080, size: 5570560, alignment 8192
Buffers allocated for reconfiguration
*[h264 @ 0x4a260] decoding for stream 0 failed*

Stop Decoder
De-Initialized Decoder
De-Initialized Params
*[h264 @ 0x4a260] Could not find codec parameters for stream 0 (Video: h264
(High), none, 1920x1080): unspecified pixel format
*Consider increasing the value for the 'analyzeduration' and 'probesize'
options
Input #0, h264, from 'no_mans_sky_1080p_10sec.h264':
  Duration: N/A, bitrate: N/A
Stream #0:0: Video: h264 (High), none, 1920x1080, 12.50 fps, 25 tbr,
1200k tbn, 25 tbc
File 'out_1080p.yuv' already exists. Overwrite ? [y/N] n
Not overwriting - exiting

Please help.




--
View this message in context: 
http://libav-users.943685.n4.nabble.com/Libav-user-decoding-for-stream-0-failed-tp4662372.html
Sent from the libav-users mailing list archive at Nabble.com.
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

[Libav-user] one question about network blocking issue

[qw]

Hi,

I'm making program to read and write rtmp av stream. If network is bad, some 
ffmpeg functions will block indefinitely.

The rtmp application will use the following functions, including 
avformat_open_input(), avformat_find_stream_info(), 
avformat_alloc_output_context2(), avio_open(), avformat_write_header(), 
av_read_frame(), av_interleaved_write_frame(), av_write_trailer(), 
avformat_close_input(), and avformat_free_context().

The above functions are used in ffmpeg and transcoding binary programs.

Which function has indefinite-block issue? How to avoid indefinite-block issue?

Thanks!

Regards

Andrew
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

[Libav-user] how to deal with network timeout

[qw]

Hi,

I'm making program to read and write rtmp stream to server. Many ffmpeg 
functions are related in network operation, such as connection, read and write:

avformat_open_input(), avformat_find_stream_info(), av_read_frame(), and 
av_interleaved_write_frame().

If network is not good, avformat_open_input() and av_read_frame() will wait 
indefinitely. How to deal with indefinite-waiting issue?

Thanks!

Regards

Andrew
___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

[Libav-user] One question about timeout in rtmp

[qw]

Hi,

I use native rtmp in ffmpeg 3.1.1 to demuxer rtmp stream from nginx server. 
avformat_open_input() is used to open input rtmp stream. Native rtmp plugin 
supports 'timeout' option as shown below:

  -timeout   .D.. Maximum timeout (in seconds) to wait 
for incoming connections. -1 is infinite. Implies -rtmp_listen 1 (from INT_MIN 
to INT_MAX) (default -1)

I add timeout of 10 seconds to rtmp option set, and call avformat_open_input().

AVDictionary *format_opts = NULL;
av_dict_set(_opts, "timeout", "10", 0);
avformat_open_input(fmt-ctx, rtmp-url, NULL, _opts);

But avformat_open_input() will return immediately with error messages as 
follows:

[rtmp @ 0x8ff9a0] Cannot open connection 
tcp://localhost:1935?listen_timeout=1
Cannot open input rtmp url:
rtmp://localhost:1935/live1/abc!
Fail to call openInputLiveStream()!

nginx server didn't provide live streaming service. It was expected that 
avformat_open_input() would return in 10 seconds with error mesage. But why did 
the function return immediately?

Thanks!

Regards

Andrew


___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user

Re: [Libav-user] ffmpeg command line for video rendered from set of image snapshots

[Carl Eugen Hoyos]

Josef Vosyka  writes:

> ffmpeg -start_number 1 -framerate 2 -i img_%d.jpg 
> -c:v h264 -profile:v baseline -r 25 -s 208:160 movie.mp4

Complete, uncut console output missing.

Generally, this mailing list is for questions using the 
libraries, ffmpeg-user is for questions regarding 
command line usage.

Carl Eugen

___
Libav-user mailing list
Libav-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/libav-user