[FFmpeg-devel] [ffmpeg-devel] [PATCH 2/4] lavfi: add asink_abuffer - audio sink buffer filter

[Stefano Sabatini]

On date Wednesday 2011-07-27 01:05:18 +0300, Mina Nagy Zaki encoded:
> ---
>  libavfilter/Makefile        |    1 +
>  libavfilter/allfilters.c    |    1 +
>  libavfilter/asink_abuffer.c |   91 +++++++++++++++++++++++++++++++++++++++++++
>  libavfilter/asink_abuffer.h |   44 +++++++++++++++++++++
>  4 files changed, 137 insertions(+), 0 deletions(-)
>  create mode 100644 libavfilter/asink_abuffer.c
>  create mode 100644 libavfilter/asink_abuffer.h
> 
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 686fd30..83b906d 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -23,6 +23,7 @@ OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o
>  
>  OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
>  
> +OBJS-$(CONFIG_ABUFFERSINK_FILTER)            += asink_abuffer.o
>  OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o
>  
>  OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 49be7b7..b812ff7 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -40,6 +40,7 @@ void avfilter_register_all(void)
>      REGISTER_FILTER (ABUFFER,     abuffer,     asrc);
>      REGISTER_FILTER (ANULLSRC,    anullsrc,    asrc);
>  
> +    REGISTER_FILTER (ABUFFER,     abuffersink, asink);
>      REGISTER_FILTER (ANULLSINK,   anullsink,   asink);
>  
>      REGISTER_FILTER (BLACKFRAME,  blackframe,  vf);
> diff --git a/libavfilter/asink_abuffer.c b/libavfilter/asink_abuffer.c
> new file mode 100644
> index 0000000..96a32c1
> --- /dev/null
> +++ b/libavfilter/asink_abuffer.c
> @@ -0,0 +1,91 @@
> +/*
> + * Copyright (c) 2011 Stefano Sabatini
> + * Copyright (c) 2011 Mina Nagy Zaki
> + *
> + * 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
> + */
> +
> +/**
> + * @file
> + * audio buffer sink
> + */
> +
> +#include "avfilter.h"
> +#include "asink_abuffer.h"
> +
> +static void filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref)
> +{
> +}
> +
> +static int init(AVFilterContext *ctx, const char *args, void *opaque)
> +{

> +    if (!opaque)
> +        return AVERROR(EINVAL);

Give a clue to the user why it failed.

> +    memcpy(ctx->priv, opaque, sizeof(ABufferSinkContext));
> +
> +    return 0;
> +}
> +

> +static int query_formats(AVFilterContext *ctx)
> +{
> +    ABufferSinkContext *abuffersink = ctx->priv;
> +    AVFilterFormats *formats;
> +
> +    formats = NULL;
> +    avfilter_add_format(&formats, abuffersink->sample_fmt);
> +    avfilter_set_common_sample_formats(ctx, formats);
> +
> +    formats = NULL;
> +    avfilter_add_format(&formats, abuffersink->channel_layout);
> +    avfilter_set_common_channel_layouts(ctx, formats);
> +
> +    formats = NULL;
> +    avfilter_add_format(&formats, AVFILTER_PACKED); //FIXME
> +    avfilter_set_common_packing_formats(ctx, formats);
> +
> +    return 0;

Note: maybe we should handle possible errors:
if ((ret = avfilter_...) < 0)
   goto end;
...
end:
return ret;

> +}
> +
> +int av_asink_abuffer_get_audio_buffer_ref(AVFilterContext *abuffer_asink,
> +                              AVFilterBufferRef **samplesref)

Maybe add flags, for consistency and extensibility.

> +{
> +    int ret;
> +
> +    if ((ret = avfilter_request_frame(abuffer_asink->inputs[0])))
> +        return ret;
> +    if (!abuffer_asink->inputs[0]->cur_buf)
> +        return AVERROR(EINVAL);
> +    *samplesref = abuffer_asink->inputs[0]->cur_buf;
> +    abuffer_asink->inputs[0]->cur_buf = NULL;
> +
> +    return 0;
> +}
> +
> +AVFilter avfilter_asink_abuffersink = {
> +    .name      = "abuffersink",

missing description

> +    .init      = init,
> +    .priv_size = sizeof(ABufferSinkContext),
> +    .query_formats = query_formats,
> +
> +    .inputs    = (AVFilterPad[]) {{ .name           = "default",
> +                                    .type           = AVMEDIA_TYPE_AUDIO,
> +                                    .filter_samples = filter_samples,
> +                                    .min_perms      = AV_PERM_READ, },
> +                                  { .name = NULL }},
> +    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
> +};
> +
> diff --git a/libavfilter/asink_abuffer.h b/libavfilter/asink_abuffer.h
> new file mode 100644
> index 0000000..9105840
> --- /dev/null
> +++ b/libavfilter/asink_abuffer.h
> @@ -0,0 +1,44 @@
> +/*
> + * 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
> + */
> +
> +#ifndef AVFILTER_ASINK_BUFFER_H
> +#define AVFILTER_ASINK_BUFFER_H

Not consistent with the filename.

> +
> +/**
> + * @file
> + * audio buffer sink API
> + */
> +
> +#include "avfilter.h"
> +
> +typedef struct {
> +    enum AVSampleFormat sample_fmt;
> +    int64_t channel_layout;
> +} ABufferSinkContext;

Not sure it is a good idea to use opaque for passing information,
anyway since this is not still public and we can tweak it later I
won't insist on this.

> +
> +
> +/**
> + * Get a video buffer data from buffer_sink and put it in picref.
> + *

> + * @param abuffer_sink pointer to a buffer sink context

to an "abuffersink" context

the name of the sink has to be specified explicitely, since that's
what the user must use.

> + * @return >= 0 in case of success, a negative AVERROR code in case of failure
> + */
> +int av_asink_abuffer_get_audio_buffer_ref(AVFilterContext *abuffer_asink,
> +                                          AVFilterBufferRef **samplesref);
> +

> +#endif /* AVFILTER_VSINK_BUFFER_H */

Typo.