lavfi: add ashowinfo filter

It can be useful for debugging.

Based on a patch by Stefano Sabatini <stefano.sabatini-lala@poste.it>

Changelog

@@ -4,6 +4,7 @@ releases are sorted from youngest to oldest.
 version <next>:
 - metadata (INFO tag) support in WAV muxer
 - support for building DLLs using MSVC
+- ashowinfo audio filter
 
 
 version 9_beta1:

doc/filters.texi

@@ -175,6 +175,47 @@ stream ends. The default value is 2 seconds.
 
 Pass the audio source unchanged to the output.
 
+@section ashowinfo
+
+Show a line containing various information for each input audio frame.
+The input audio is not modified.
+
+The shown line contains a sequence of key/value pairs of the form
+@var{key}:@var{value}.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 0
+
+@item pts
+Presentation timestamp of the input frame, in time base units; the time base
+depends on the filter input pad, and is usually 1/@var{sample_rate}.
+
+@item pts_time
+presentation timestamp of the input frame in seconds
+
+@item fmt
+sample format
+
+@item chlayout
+channel layout
+
+@item rate
+sample rate for the audio frame
+
+@item nb_samples
+number of samples (per channel) in the frame
+
+@item checksum
+Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
+the data is treated as if all the planes were concatenated.
+
+@item plane_checksums
+A list of Adler-32 checksums for each data plane.
+@end table
+
 @section asplit
 
 Split input audio into several identical outputs.

libavfilter/Makefile

@@ -28,6 +28,7 @@ OBJS-$(CONFIG_AFIFO_FILTER)                  += fifo.o
 OBJS-$(CONFIG_AFORMAT_FILTER)                += af_aformat.o
 OBJS-$(CONFIG_AMIX_FILTER)                   += af_amix.o
 OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o
+OBJS-$(CONFIG_ASHOWINFO_FILTER)              += af_ashowinfo.o
 OBJS-$(CONFIG_ASPLIT_FILTER)                 += split.o
 OBJS-$(CONFIG_ASYNCTS_FILTER)                += af_asyncts.o
 OBJS-$(CONFIG_CHANNELMAP_FILTER)             += af_channelmap.o

libavfilter/af_ashowinfo.c

+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * filter for showing textual audio frame information
+ */
+
+#include <inttypes.h>
+#include <stddef.h>
+
+#include "libavutil/adler32.h"
+#include "libavutil/audioconvert.h"
+#include "libavutil/common.h"
+#include "libavutil/mem.h"
+#include "libavutil/samplefmt.h"
+
+#include "audio.h"
+#include "avfilter.h"
+
+typedef struct AShowInfoContext {
+    /**
+     * Scratch space for individual plane checksums for planar audio
+     */
+    uint32_t *plane_checksums;
+
+    /**
+     * Frame counter
+     */
+    uint64_t frame;
+} AShowInfoContext;
+
+static int config_input(AVFilterLink *inlink)
+{
+    AShowInfoContext *s = inlink->dst->priv;
+    int channels = av_get_channel_layout_nb_channels(inlink->channel_layout);
+    s->plane_checksums = av_malloc(channels * sizeof(*s->plane_checksums));
+    if (!s->plane_checksums)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static void uninit(AVFilterContext *ctx)
+{
+    AShowInfoContext *s = ctx->priv;
+    av_freep(&s->plane_checksums);
+}
+
+static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AShowInfoContext *s  = ctx->priv;
+    char chlayout_str[128];
+    uint32_t checksum = 0;
+    int channels    = av_get_channel_layout_nb_channels(buf->audio->channel_layout);
+    int planar      = av_sample_fmt_is_planar(buf->format);
+    int block_align = av_get_bytes_per_sample(buf->format) * (planar ? 1 : channels);
+    int data_size   = buf->audio->nb_samples * block_align;
+    int planes      = planar ? channels : 1;
+    int i;
+
+    for (i = 0; i < planes; i++) {
+        uint8_t *data = buf->extended_data[i];
+
+        s->plane_checksums[i] = av_adler32_update(0, data, data_size);
+        checksum = i ? av_adler32_update(checksum, data, data_size) :
+                       s->plane_checksums[0];
+    }
+
+    av_get_channel_layout_string(chlayout_str, sizeof(chlayout_str), -1,
+                                 buf->audio->channel_layout);
+
+    av_log(ctx, AV_LOG_INFO,
+           "n:%"PRIu64" pts:%"PRId64" pts_time:%f "
+           "fmt:%s chlayout:%s rate:%d nb_samples:%d "
+           "checksum:%08X ",
+           s->frame, buf->pts, buf->pts * av_q2d(inlink->time_base),
+           av_get_sample_fmt_name(buf->format), chlayout_str,
+           buf->audio->sample_rate, buf->audio->nb_samples,
+           checksum);
+
+    av_log(ctx, AV_LOG_INFO, "plane_checksums: [ ");
+    for (i = 0; i < planes; i++)
+        av_log(ctx, AV_LOG_INFO, "%08X ", s->plane_checksums[i]);
+    av_log(ctx, AV_LOG_INFO, "]\n");
+
+    s->frame++;
+    return ff_filter_samples(inlink->dst->outputs[0], buf);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name       = "default",
+        .type             = AVMEDIA_TYPE_AUDIO,
+        .get_audio_buffer = ff_null_get_audio_buffer,
+        .config_props     = config_input,
+        .filter_samples   = filter_samples,
+        .min_perms        = AV_PERM_READ,
+    },
+    { NULL },
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL },
+};
+
+AVFilter avfilter_af_ashowinfo = {
+    .name        = "ashowinfo",
+    .description = NULL_IF_CONFIG_SMALL("Show textual information for each audio frame."),
+    .priv_size   = sizeof(AShowInfoContext),
+    .uninit      = uninit,
+    .inputs      = inputs,
+    .outputs     = outputs,
+};

libavfilter/allfilters.c

@@ -39,6 +39,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (AFORMAT,     aformat,     af);
     REGISTER_FILTER (AMIX,        amix,        af);
     REGISTER_FILTER (ANULL,       anull,       af);
+    REGISTER_FILTER (ASHOWINFO,   ashowinfo,   af);
     REGISTER_FILTER (ASPLIT,      asplit,      af);
     REGISTER_FILTER (ASYNCTS,     asyncts,     af);
     REGISTER_FILTER (CHANNELMAP,  channelmap,  af);

libavfilter/version.h

@@ -29,7 +29,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  1
+#define LIBAVFILTER_VERSION_MINOR  2
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \