From: yu.dongliang <18588496441@163.com>
Date: Sat, 15 Apr 2023 04:20:07 +0000 (+0800)
Subject: ffmpeg_alsa: add output filter
X-Git-Url: http://baseworks.info/?a=commitdiff_plain;h=fbc5a4102f750fd6ce88d66fdb75be503c3adc6b;p=simplay.git

ffmpeg_alsa: add output filter
---

diff --git a/simp.h b/simp.h
index cf706c6..372d95f 100644
--- a/simp.h
+++ b/simp.h
@@ -55,11 +55,16 @@ typedef struct {
 
 	AVAudioFifo*      afifo;
 
+	AVFilterContext*  obuffersrc_ctx;
+	AVFilterContext*  obuffersink_ctx;
+	AVFilterGraph*    ograph;
+
 	int               idx_in;
 	int               idx_out;
 
 	AVFrame*          iframe;
 	AVFrame*          oframe;
+	AVFrame*          fframe;
 
 	AVPacket*         ipkt;
 	AVPacket*         opkt;
diff --git a/simp_ffmpeg_alsa.c b/simp_ffmpeg_alsa.c
index 214c379..794bf58 100644
--- a/simp_ffmpeg_alsa.c
+++ b/simp_ffmpeg_alsa.c
@@ -1,6 +1,95 @@
 #include"simp_ffmpeg.h"
 #include"scf_def.h"
 
+static int _output_filter_init(simp_audio_t* priv)
+{
+    char args[512];
+    int  ret = 0;
+
+    const AVFilter *abuffersrc     = avfilter_get_by_name("abuffer");
+    const AVFilter *abuffersink    = avfilter_get_by_name("abuffersink");
+
+	AVFilterInOut  *outputs        = NULL;
+    AVFilterInOut  *inputs         = NULL;
+
+	const char     *afilters_descr = "[in]aresample=44100[out]";
+
+	priv->ograph = avfilter_graph_alloc();
+	if (!priv->ograph) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	snprintf(args, sizeof(args),
+			"time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=%#x",
+			1, 44100, 44100,
+			av_get_sample_fmt_name(AV_SAMPLE_FMT_FLTP),
+			AV_CH_LAYOUT_STEREO);
+
+	printf("%s\n", args);
+
+	ret = avfilter_graph_create_filter(&priv->obuffersrc_ctx, abuffersrc, "in", args, NULL, priv->ograph);
+	if (ret < 0)
+		goto end;
+
+	outputs = avfilter_inout_alloc();
+	if (!outputs) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	outputs->name       = av_strdup("in");
+	outputs->filter_ctx = priv->obuffersrc_ctx;
+	outputs->pad_idx    = 0;
+	outputs->next       = NULL;
+
+	const enum AVSampleFormat sample_fmts[]  = {priv->codec_out->sample_fmt,     -1};
+	const int                 sample_rates[] = {priv->codec_out->sample_rate,    -1};
+	const int64_t             layouts[]      = {priv->codec_out->channel_layout, -1};
+
+	ret = avfilter_graph_create_filter(&priv->obuffersink_ctx, abuffersink, "out", NULL, NULL, priv->ograph);
+    if (ret < 0)
+        goto end;
+
+	inputs = avfilter_inout_alloc();
+	if (!inputs) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+    inputs->name       = av_strdup("out");
+    inputs->filter_ctx = priv->obuffersink_ctx;
+    inputs->pad_idx    = 0;
+    inputs->next       = NULL;
+
+	ret = av_opt_set_int_list(priv->obuffersink_ctx, "sample_fmts", sample_fmts, -1, AV_OPT_SEARCH_CHILDREN);
+	if (ret < 0)
+		goto end;
+
+	ret = av_opt_set_int_list(priv->obuffersink_ctx, "channel_layouts", layouts, -1, AV_OPT_SEARCH_CHILDREN);
+	if (ret < 0)
+		goto end;
+
+	ret = av_opt_set_int_list(priv->obuffersink_ctx, "sample_rates", sample_rates, -1, AV_OPT_SEARCH_CHILDREN);
+	if (ret < 0)
+		goto end;
+
+	if ((ret = avfilter_graph_parse_ptr(priv->ograph, afilters_descr, &inputs, &outputs, NULL)) < 0) {
+		scf_loge("\n");
+		goto end;
+	}
+
+	if ((ret = avfilter_graph_config(priv->ograph, NULL)) < 0) {
+		scf_loge("\n");
+		goto end;
+	}
+
+end:
+    avfilter_inout_free(&inputs);
+    avfilter_inout_free(&outputs);
+    return ret;
+}
+
 static int _audio_input_init(simp_audio_t* priv, const char* path)
 {
 	AVInputFormat* in = av_find_input_format("alsa");
@@ -117,10 +206,20 @@ static int _audio_output_init(simp_audio_t* priv, const char* path)
 		return ret;
 	}
 
+	ret = _output_filter_init(priv);
+	if (ret < 0) {
+		scf_loge("output filter init error, ret: %d, %s\n", ret, av_err2str(ret));
+		return ret;
+	}
+
 	priv->afifo = av_audio_fifo_alloc(priv->codec_out->sample_fmt, 2, 1024);
 	if (!priv->afifo)
 		return -ENOMEM;
 
+	priv->fframe = av_frame_alloc();
+	if (!priv->fframe)
+		return -ENOMEM;
+
 	priv->opkt = av_packet_alloc();
 	if (!priv->opkt)
 		return -ENOMEM;
@@ -154,6 +253,9 @@ void simp_audio_free(simp_audio_t* priv)
 		if (priv->codec_out)
 			avcodec_close(priv->codec_out);
 
+		if (priv->ograph)
+			avfilter_graph_free(&priv->ograph);
+
 		if (priv->afifo)
 			av_audio_fifo_free(priv->afifo);
 
@@ -163,6 +265,9 @@ void simp_audio_free(simp_audio_t* priv)
 		if (priv->oframe)
 			av_frame_free(&priv->oframe);
 
+		if (priv->fframe)
+			av_frame_free(&priv->fframe);
+
 		if (priv->ipkt)
 			av_packet_free(&priv->ipkt);
 
@@ -251,17 +356,31 @@ static int __output_audio(simp_avio_t* io, AVCodecContext* c, AVPacket* pkt, AVF
 		scf_list_del(&f->list);
 		pthread_mutex_unlock(&io->mutex);
 
-		ret = av_audio_fifo_write(priv->afifo, (void**)f->frame->data, f->frame->nb_samples);
-
 		scf_logd("priv->aidx: %d, frame->pts: %ld, frame->nb_samples: %d, afifo->size: %d\n",
 				priv->aidx, f->frame->pts, f->frame->nb_samples, av_audio_fifo_size(priv->afifo));
 
+		ret = av_buffersrc_add_frame_flags(priv->obuffersrc_ctx, f->frame, AV_BUFFERSRC_FLAG_KEEP_REF);
 		simp_frame_free(f);
 		f = NULL;
-
 		if (ret < 0)
 			return ret;
 
+		while (1) {
+			ret = av_buffersink_get_frame(priv->obuffersink_ctx, priv->fframe);
+
+			if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
+				break;
+			} else if (ret < 0) {
+				scf_loge("av_buffersink_get_frame error, ret: %s\n", av_err2str(ret));
+				return ret;
+			}
+
+			ret = av_audio_fifo_write(priv->afifo, (void**)priv->fframe->data, priv->fframe->nb_samples);
+			av_frame_unref(priv->fframe);
+			if (ret < 0)
+				return ret;
+		}
+
 	} else {
 		pthread_mutex_unlock(&io->mutex);
 	}