[FFmpeg-devel] libavfilter/af_ambisonic.c Added File for Ambisonic Filter

Patch details:
File added avfilter/af_ambisonic.c
Entries made in avfilter/Makefile and avfilter/allfilters.c
Entry made in Changelog




On Sat, Mar 11, 2017 at 4:29 PM, Sanchit Sinha <sanchit15083@iiitd.ac.in>
wrote:

>
> Thanks Andy for the valuable info! It would be good to talk and learn from
> these guys, especially for an amateur like me. :)
>
> On Sat, Mar 11, 2017 at 4:23 PM, Andy Furniss <adf.lists@gmail.com> wrote:
>
>> Paul B Mahol wrote:
>>
>>> On 3/11/17, Andy Furniss <adf.lists@gmail.com> wrote:
>>>
>>>> Sanchit Sinha wrote:
>>>>
>>>>> libavfilter/af_ambisonic.c | 139
>>>>>
>>>>
>>>> +        w=(float *)(*(in->extended_data)+itr);
>>>>> +        x=(float *)(*(in->extended_data+1)+itr);
>>>>> +        y=(float *)(*(in->extended_data+2)+itr);
>>>>> +
>>>>> +        *lf = root8 * (2*(*w)+*x+*y);
>>>>> +        *lb = root8 * (2*(*w)-*x+*y);
>>>>> +        *rb = root8 * (2*(*w)-*x-*y);
>>>>> +        *rf = root8 * (2*(*w)+*x-*y);
>>>>>
>>>>
>>>> Seems a bit misleading to call something ambisonic if all it will
>>>> do is 2d, so partial b-format to (square?) 4 channel.
>>>>
>>>> Why not be more specific in the name so the limitation is clear.
>>>>
>>>
>>> This is just for qualification task. Later filter willl be extended.
>>>
>>> It will not be applied as is in tree.
>>>
>>
>> Ahh, OK.
>>
>> A complicated subject.
>>
>> Sanchit, in case you don't know, some of the people who were around at
>> the birth of ambisonics, plus ambdec author can be found on the list -
>>
>> https://mail.music.vt.edu/mailman/listinfo/sursound
>>
>>
>>
>>
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>
>
>
> --
> Sanchit Sinha
> B.Tech- CSE
> IIIT-Delhi
> Roll-2015083
>

On 3/11/17, Sanchit Sinha <sanchit15083@iiitd.ac.in> wrote:
> Patch details:
> File added avfilter/af_ambisonic.c
> Entries made in avfilter/Makefile and avfilter/allfilters.c
> Entry made in Changelog

Learn not to top post.

> From bb9915658d1089e36f5b3131ec5851a058a57c62 Mon Sep 17 00:00:00 2001
> From: Sanchit Sinha <sanchit15083@iiitd.ac.in>
> Date: Sat, 11 Mar 2017 17:04:47 +0530
> Subject: [PATCH] avfiler/af_ambisonic.c: file added avfilter/allfilters.c and
>  Makefile: entry added Changelog: entry mentioned
>
> ---
>  Changelog                  |   1 +
>  libavfilter/Makefile       |   1 +
>  libavfilter/af_ambisonic.c | 137 +++++++++++++++++++++++++++++++++++++++++++++
>  libavfilter/allfilters.c   |   1 +
>  4 files changed, 140 insertions(+)
>  create mode 100644 libavfilter/af_ambisonic.c
>
> diff --git a/Changelog b/Changelog
> index 13628ca..b917ac2 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -26,6 +26,7 @@ version <next>:
>  - native Opus encoder
>  - ScreenPressor decoder
>  - incomplete ClearVideo decoder
> +- Ambisonic Decoder
>
>  version 3.2:
>  - libopenmpt demuxer
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 0ba1c74..16fd612 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -47,6 +47,7 @@ OBJS-$(CONFIG_ALOOP_FILTER)                  += f_loop.o
>  OBJS-$(CONFIG_AMERGE_FILTER)                 += af_amerge.o
>  OBJS-$(CONFIG_AMETADATA_FILTER)              += f_metadata.o
>  OBJS-$(CONFIG_AMIX_FILTER)                   += af_amix.o
> +OBJS-$(CONFIG_AMBISONIC_FILTER)              += af_ambisonic.o

B comes before I

>  OBJS-$(CONFIG_ANEQUALIZER_FILTER)            += af_anequalizer.o
>  OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o
>  OBJS-$(CONFIG_APAD_FILTER)                   += af_apad.o
> diff --git a/libavfilter/af_ambisonic.c b/libavfilter/af_ambisonic.c
> new file mode 100644
> index 0000000..32f3c0c
> --- /dev/null
> +++ b/libavfilter/af_ambisonic.c
> @@ -0,0 +1,137 @@
> +/*
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <stdio.h>
> +#include "libavutil/avstring.h"
> +#include "libavutil/channel_layout.h"
> +#include "libavutil/opt.h"
> +#include "audio.h"
> +#include "avfilter.h"
> +#include "formats.h"
> +#include <math.h>
> +
> +typedef struct AmbisonicContext {
> +	const AVClass *class;
> +	/*Not needed, if any new variables are to be used, this struct can be populated(f)*/
> +
> +} AmbisonicContext;
> +
> +#define OFFSET(x) offsetof(AmbisonicContext, x)
> +
> +static const AVOption ambisonic_options[] = {  //square will be an option
> +{NULL}
> +};
> +
> +AVFILTER_DEFINE_CLASS(ambisonic);
> +static int query_formats(AVFilterContext *ctx)
> +{
> +	AVFilterFormats *formats = NULL;
> +	AVFilterChannelLayouts *layout = NULL;
> +	int ret;
> +	if ((ret = ff_add_format     (&formats, AV_SAMPLE_FMT_FLTP   )) < 0 ||
> +	(ret = ff_set_common_formats     (ctx    , formats )) < 0 ||
> +	(ret = ff_add_channel_layout     (&layout , AV_CH_LAYOUT_4POINT0)) < 0 ||
> +	(ret = ff_set_common_channel_layouts (ctx    , layout   )) < 0)
> +	return ret;
> +	formats = ff_all_samplerates();
> +	return ff_set_common_samplerates(ctx, formats);
> +}
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> +{
> +	AVFilterContext *ctx = inlink->dst;
> +	AVFilterLink *outlink = ctx->outputs[0];
> +	/*If variables used, this has to be created*/
> +	// AmbisonicContext *s = ctx->priv;
> +	// const float *src = (const float *)in->data[0];
> +	// float *dst;
> +	AVFrame *out;
> +	int itr;
> +	float *w,*x,*y;
> +	float root8= sqrt(8);
> +	float lf=0,lb=0,rb=0,rf=0;
> +
> +	if (av_frame_is_writable(in))
> +	{
> +		out = in;
> +	}
> +	else
> +	{

Code style is awful.

> +		out = ff_get_audio_buffer(inlink, in->nb_samples);
> +		if (!out)
> +		{

Please do not change code style of code you copied.
Instead follow its style to the end.

> +			av_frame_free(&in);
> +			return AVERROR(ENOMEM);
> +		}
> +		av_frame_copy_props(out, in);
> +	}
> +
> +	/*If planar samples are used, output must be put in dst*/
> +	//dst = (float *)out->data[0];

Remove those remnants.

> +
> +	w=(float *)in->extended_data[0];
> +	x=(float *)in->extended_data[1];
> +	y=(float *)in->extended_data[2];
> +
> +	for(itr=0;itr<in->nb_samples;itr++)
> +	{

For loops { comes in line above.

> +		/*Float pointers to the samples*/

Please remove this, maybe this is still hopeful for you, but
I really hope not. If you still have problems with pointers I advise
you to look at other projects.

> +
> +		lf = root8 * (2*(w[itr])+x[itr]+y[itr]);
> +		lb = root8 * (2*(w[itr])-x[itr]+y[itr]);
> +		rb = root8 * (2*(w[itr])-x[itr]-y[itr]);
> +		rf = root8 * (2*(w[itr])+x[itr]-y[itr]);
> +
> +		out->extended_data[0][itr]= lf;
> +		out->extended_data[1][itr]= lb;
> +		out->extended_data[2][itr]= rb;
> +		out->extended_data[3][itr]= rf;

This is wrong. Must use similar pointers like what was done for
in->extended_data.

> +	}
> +
> +	if (out != in)
> +	av_frame_free(&in);

Wrong indentation.

> +	return ff_filter_frame(outlink, out);
> +}
> +
> +static const AVFilterPad inputs[] = {
> +	{
> +	.name    = "default",

Indentation is wrong.

> +	.type    = AVMEDIA_TYPE_AUDIO,
> +	.filter_frame = filter_frame,
> +	// .config_props = config_input,

Remove commented out stuff.

> +	},
> +	{ NULL }
> +};
> +
> +static const AVFilterPad outputs[] = {
> +	{
> +	.name = "default",
> +	.type = AVMEDIA_TYPE_AUDIO,
> +	},
> +	{ NULL }
> +};
> +
> +AVFilter ff_af_ambisonic = {
> +	.name      = "ambisonic",
> +	.description    = NULL_IF_CONFIG_SMALL("An ambisonic filter"),
> +	.query_formats  = query_formats,
> +	.priv_size    = sizeof(AmbisonicContext),
> +	.priv_class  = &ambisonic_class,
> +	// .uninit   = uninit,

Remove commented out stuff.

> +	.inputs  = inputs,
> +	.outputs    = outputs,
> +};
> \ No newline at end of file
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index df1af8d..59aeb6d 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -56,6 +56,7 @@ static void register_all(void)
>      REGISTER_FILTER(ALIMITER,       alimiter,       af);
>      REGISTER_FILTER(ALLPASS,        allpass,        af);
>      REGISTER_FILTER(ALOOP,          aloop,          af);
> +    REGISTER_FILTER(AMBISONIC,      ambisonic,      af);
>      REGISTER_FILTER(AMERGE,         amerge,         af);
>      REGISTER_FILTER(AMETADATA,      ametadata,      af);
>      REGISTER_FILTER(AMIX,           amix,           af);
> --
> 2.7.4
>