asrc_anullsrc: implement a request_frame callback for returning frames

This is mainly useful for filters (like the sox synth), which overwrite the content of the passed data.

Stefano Sabatini committed 15 years ago

Commit e72aa521 parent 44ab77d3 files · +31 −7Browse files

Unified · Split

3 files

doc/filters.texi +8 −2
libavfilter/asrc_anullsrc.c +22 −4
libavfilter/avfilter.h +1 −1

@@ -309,8 +309,10 @@ value is "-1". · 308 unmodified lines
309	309
310	310	@section anullsrc
311	311
312		−Null audio source, never return audio frames. It is mainly useful as a
313		−template and to be employed in analysis / debugging tools.
	312	+Null audio source, return unprocessed audio frames. It is mainly useful
	313	+as a template and to be employed in analysis / debugging tools, or as
	314	+the source for filters which ignore the input data (for example the sox
	315	+synth filter).
314	316
315	317	It accepts an optional sequence of @var{key}=@var{value} pairs,
316	318	separated by ":".
@@ -331,6 +333,10 @@ is "stereo". · 14 unmodified lines
331	333	Check the channel_layout_map definition in
332	334	@file{libavcodec/audioconvert.c} for the mapping between strings and
333	335	channel layout values.
	336	+
	337	+@item nb_samples, n
	338	+Set the number of samples per requested frames.
	339	+
334	340	@end table
335	341
336	342	Follow some examples:

libavfilter/asrc_anullsrc.c+22−4

@@ -33,6 +33,8 @@ typedef struct { · 32 unmodified lines
33	33	int64_t channel_layout;
34	34	char *sample_rate_str;
35	35	int sample_rate;
	36	+ int nb_samples; ///< number of samples per requested frame
	37	+ int64_t pts;
36	38	} ANullContext;
37	39
38	40	#define OFFSET(x) offsetof(ANullContext, x)
@@ -42,6 +44,8 @@ static const AVOption anullsrc_options[]= { · 3 unmodified lines
42	44	{ "cl", "set channel_layout", OFFSET(channel_layout_str), FF_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0 },
43	45	{ "sample_rate", "set sample rate", OFFSET(sample_rate_str) , FF_OPT_TYPE_STRING, {.str = "44100"}, 0, 0 },
44	46	{ "r", "set sample rate", OFFSET(sample_rate_str) , FF_OPT_TYPE_STRING, {.str = "44100"}, 0, 0 },
	47	+ { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), FF_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX },
	48	+ { "n", "set the number of samples per requested frame", OFFSET(nb_samples), FF_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX },
45	49	{ NULL },
46	50	};
47	51
@@ -92,15 +96,29 @@ static int config_props(AVFilterLink *outlink) · 44 unmodified lines
92	96	chans_nb = av_get_channel_layout_nb_channels(priv->channel_layout);
93	97	av_get_channel_layout_string(buf, sizeof(buf), chans_nb, priv->channel_layout);
94	98	av_log(outlink->src, AV_LOG_INFO,
95		− "sample_rate:%d channel_layout:%"PRId64 " channel_layout_description:'%s'\n",
96		− priv->sample_rate, priv->channel_layout, buf);
	99	+ "sample_rate:%d channel_layout:%"PRId64 " channel_layout_description:'%s' nb_samples:%d\n",
	100	+ priv->sample_rate, priv->channel_layout, buf, priv->nb_samples);
97	101
98	102	return 0;
99	103	}
100	104
101		−static int request_frame(AVFilterLink *link)
	105	+static int request_frame(AVFilterLink *outlink)
102	106	{
103		− return -1;
	107	+ ANullContext *null = outlink->src->priv;
	108	+ AVFilterBufferRef *samplesref;
	109	+
	110	+ samplesref =
	111	+ avfilter_get_audio_buffer(outlink, AV_PERM_WRITE, null->nb_samples);
	112	+ samplesref->pts = null->pts;
	113	+ samplesref->pos = -1;
	114	+ samplesref->audio->channel_layout = null->channel_layout;
	115	+ samplesref->audio->sample_rate = outlink->sample_rate;
	116	+
	117	+ avfilter_filter_samples(outlink, avfilter_ref_buffer(samplesref, ~0));
	118	+ avfilter_unref_buffer(samplesref);
	119	+
	120	+ null->pts += null->nb_samples;
	121	+ return 0;
104	122	}
105	123
106	124	AVFilter avfilter_asrc_anullsrc = {

libavfilter/avfilter.h+1−1

@@ -30,7 +30,7 @@ · 29 unmodified lines
30	30
31	31	#define LIBAVFILTER_VERSION_MAJOR 2
32	32	#define LIBAVFILTER_VERSION_MINOR 43
33		−#define LIBAVFILTER_VERSION_MICRO 1
	33	+#define LIBAVFILTER_VERSION_MICRO 2
34	34
35	35	#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
36	36	LIBAVFILTER_VERSION_MINOR, \

asrc_anullsrc: implement a request_frame callback for returning frames

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