requires free packet

CMakeLists.txt

@@ -0,0 +1,34 @@
+cmake_minimum_required (VERSION 2.8.11)
+project (spdif-decoder)
+
+add_executable (spdif-decoder 
+    codechandler.c 
+    helper.c
+    myspdif.c
+    myspdifdec.c
+    resample.c
+    spdif-loop.c
+)
+
+SET(FFMPEG ${CMAKE_CURRENT_SOURCE_DIR}/../ffmpeg-4.3.1)
+
+target_include_directories (spdif-decoder
+    PUBLIC ${FFMPEG}
+)
+
+FIND_LIBRARY(libavcodec avcodec ${FFMPEG}/libavcodec)
+FIND_LIBRARY(libavformat avformat ${FFMPEG}/libavformat)
+FIND_LIBRARY(libavdevice avdevice ${FFMPEG}/libavdevice)
+FIND_LIBRARY(libavutil avutil ${FFMPEG}/libavutil)
+FIND_LIBRARY(libswresample swresample ${FFMPEG}/libswresample)
+FIND_LIBRARY(libavfilter avfilter ${FFMPEG}/libavfilter)
+TARGET_LINK_LIBRARIES(spdif-decoder 
+    ${libavcodec}
+    ${libavformat}
+    ${libavdevice}
+    ${libavutil}
+    ${libswresample}
+    ${libavfilter}
+    ao
+    m
+)

README.md

@@ -1,31 +1,39 @@
-spdif-loop
-==========
+spdif-decoder
+=============
 
 SPDIF to 5.1 software loop decoder.  Use if you want to connect a
-digital surround signal (Dolby Digital), such as an Xbox 360 S, via
+digital surround signal (Dolby Digital), such as an Xbox 360 S or TV, via
 your PC to your 5.1 (analog) stereo.  Like a digital receiver/decoder,
 just in software.
 
+FFMPEG is licenced under the GNU Lesser General Public License version 2.1 and so is 
+this piece of software. 
 
 Requirements
 ------------
+- libasound2-dev
+- libao-dev
+- cmake
+- ffmpeg from Source https://www.ffmpeg.org/download.html (tested with 4.3.1)
 
-- ffmpeg/libav
-- libao
-
-
-Build
+Build ffmpeg shared library with a minimal set for alsa and AC3 support
 -----
+    ./configure --enable-shared --disable-static --disable-everything --enable-demuxer=spdif --enable-decoder=ac3 --enable-indev=alsa
+    make
 
-make
+Build spdif-decoder
+-----
+Prepare CMakeLists.txt - set FFMPEG Var with Path to ffmpeg (if not in ../ffmpeg-4.3.1)
 
+    cmake .
+    make
 
 Run
 ---
 
 I run it like this:
 
-    ./spdif-loop -i hw:CARD=Device -d pulse -o alsa_output.usb-0d8c_USB_Sound_Device-00-Device.analog-surround51
+    ./spdif-decoder -i hw:CARD=Device -d pulse -o alsa_output.usb-0d8c_USB_Sound_Device-00-Device.analog-surround51
 
 Alsa's `hw:CARD=Device` is my SPDIF input.  You can list your alsa devices with
 
@@ -39,7 +47,7 @@ I had to use `amixer` to set the capture source to SPIF.  In this case
     amixer -c Device set 'PCM Capture Source' 'IEC958 In'    # set input
 
 
-Contact
+Thanks to
 -------
-
+Sebastian Morgenstern <Sebastian.Morgenstern@gmail.com>
 Simon Schubert <2@0x2c.org>

codechandler.c

@@ -0,0 +1,102 @@
+/*
+ * codechandler.c
+ *
+ *  Created on: 25.04.2015
+ *      Author: sebastian
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <err.h>
+#include "resample.h"
+#include "codechandler.h"
+
+void CodecHandler_init(CodecHandler* h){
+	h->codec = NULL;
+	h->codecContext = NULL;
+	h->currentChannelCount = 0;
+	h->currentCodecID = AV_CODEC_ID_NONE;
+	h->currentSampleRate = 0;
+	h->swr = resample_init();
+	h->frame = av_frame_alloc();
+}
+void CodecHandler_deinit(CodecHandler* h){
+	resample_deinit(h->swr);
+	av_frame_free(&h->frame);
+}
+
+int CodecHandler_loadCodec(CodecHandler * handler, AVFormatContext * formatcontext){
+	if (formatcontext->nb_streams == 0){
+		printf("could not find a stream\n");
+		handler->currentCodecID = AV_CODEC_ID_NONE;
+		return -1;
+	}
+
+	if(handler->currentCodecID == formatcontext->streams[0]->codec->codec_id){
+		//Codec already loaded
+		return 0;
+	}
+
+	if(handler->codecContext != NULL){
+		CodecHandler_closeCodec(handler);
+	}
+	handler->currentCodecID = AV_CODEC_ID_NONE;
+
+	handler->codec = avcodec_find_decoder(formatcontext->streams[0]->codec->codec_id);
+	if (!handler->codec) {
+		printf("could not find codec\n");
+		return -1;
+	}else{
+		printf("found codec\n");
+	}
+	handler->codecContext = avcodec_alloc_context3(handler->codec);
+	if (!handler->codecContext)
+		errx(1, "cannot allocate codec");
+	if (avcodec_open2(handler->codecContext, handler->codec, NULL) != 0)
+		errx(1, "cannot open codec");
+	handler->currentCodecID = formatcontext->streams[0]->codec->codec_id;
+	return 0;
+}
+
+int CodecHandler_decodeCodec(CodecHandler * h, AVPacket * pkt,
+		uint8_t *outbuffer, uint32_t* bufferfilled){
+	int got_frame;
+	int processed_len = avcodec_decode_audio4(h->codecContext, h->frame, &got_frame, pkt);
+	if (processed_len < 0)
+		errx(1, "cannot decode input");
+
+	int ret = 0;
+
+	pkt->data += processed_len;
+	pkt->size -= processed_len;
+	if(h->currentChannelCount != h->codecContext->channels
+			|| h->currentSampleRate != h->codecContext->sample_rate
+			|| h->currentChannelLayout != h->codecContext->channel_layout){
+		resample_loadFromCodec(h->swr, h->codecContext);
+		printf("c: %d, s: %d\n",h->codecContext->channels, h->codecContext->sample_rate);
+		ret = 1;
+	}
+
+	swr_convert(h->swr, &outbuffer, h->frame->nb_samples, (const uint8_t **)h->frame->data, h->frame->nb_samples);
+	*bufferfilled = av_samples_get_buffer_size(NULL,
+			   h->codecContext->channels,
+			   h->frame->nb_samples,
+			   AV_SAMPLE_FMT_S16,
+			   1);
+
+	h->currentChannelCount = h->codecContext->channels;
+	h->currentSampleRate = h->codecContext->sample_rate;
+	h->currentChannelLayout = h->codecContext->channel_layout;
+	return ret;
+}
+
+
+int CodecHandler_closeCodec(CodecHandler * handler){
+	if(handler->codecContext != NULL){
+		avcodec_close(handler->codecContext);
+		avcodec_free_context(&handler->codecContext);
+	}
+	handler->codec = NULL;
+	handler->codecContext = NULL;
+	return 0;
+}

codechandler.h

@@ -0,0 +1,37 @@
+/*
+ * codechandler.h
+ *
+ *  Created on: 25.04.2015
+ *      Author: sebastian
+ */
+
+#ifndef CODECHANDLER_H_
+#define CODECHANDLER_H_
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+#include <libswresample/swresample.h>
+#include <libavutil/frame.h>
+
+typedef struct s_codechandler{
+	AVCodecContext *codecContext;
+	AVCodec * codec;
+	enum AVCodecID currentCodecID;
+	int currentChannelCount;
+	uint64_t currentChannelLayout;
+	int currentSampleRate;
+	SwrContext * swr;
+	AVFrame * frame;
+} CodecHandler;
+
+void CodecHandler_init(CodecHandler* handler);
+void CodecHandler_deinit(CodecHandler* handler);
+
+int CodecHandler_loadCodec(CodecHandler * handler, AVFormatContext * formatcontext);
+int CodecHandler_hasCodecChangend(CodecHandler * handler, AVFormatContext * formatcontext);
+
+int CodecHandler_decodeCodec(CodecHandler * h, AVPacket * pkt,
+		uint8_t *outbuffer, uint32_t* bufferfilled);
+int CodecHandler_closeCodec(CodecHandler * handler);
+
+
+#endif /* CODECHANDLER_H_ */

helper.c

@@ -0,0 +1,80 @@
+/*
+ * helper.c
+ *
+ *  Created on: 21.04.2015
+ *      Author: sebastian
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <math.h>
+
+#include <ao/ao.h>
+
+ao_device * open_output(int driver_id, ao_option *dev_opts, int bits, int channels, int sample_rate)
+{
+	printf("%d bit, %d channels, %dHz\n",
+	       bits,
+	       channels,
+	       sample_rate);
+
+	ao_sample_format out_fmt = {
+		.bits = bits,
+		.channels = channels,
+		.rate = sample_rate,
+		.byte_format = AO_FMT_NATIVE,
+		//.matrix = "L,R,BL,BR,C,LFE",
+		.matrix = "L,R,C,LFE,BL,BR",
+	};
+
+	return (ao_open_live(driver_id, &out_fmt, dev_opts));
+}
+
+int test_audio_out(int driver_id, ao_option *dev_opts)
+{
+	struct chan_map {
+		const char *name;
+		int freq;
+		int idx;
+	} map[] = {
+		/* This needs to match the order in open_output(). */
+		{ "left",	500, 0 },
+		{ "center",	500, 2 },
+		{ "right",	500, 1 },
+		{ "rear right", 500, 5 },
+		{ "rear left",	500, 4 },
+		{ "sub",	 50, 3 }
+	};
+
+	ao_device *odev = open_output(driver_id, dev_opts, 16, 6, 48000);
+	if (!odev)
+		errx(1, "cannot open audio output");
+	int ch;
+	for (ch = 0; ch < 6; ++ch) {
+		const size_t buflen = 4800; /* 1/10 of a second */
+		int16_t buf[buflen * 6];
+
+		printf("channel %d: %s\n", map[ch].idx, map[ch].name);
+
+		/* prepare sine samples */
+		memset(buf, 0, sizeof(buf));
+		int i;
+		for (i = 0; i < buflen; ++i) {
+			buf[i * 6 + map[ch].idx] = INT16_MAX / 10 * cos(2 * (3.14159265358979323846) * map[ch].freq * i / 48000.0);
+		}
+
+		/* play for 2 sec, 1 sec pause */
+		for (i = 0; i < 30; ++i) {
+			if (i == 20) {
+				/* now pause */
+				memset(buf, 0, sizeof(buf));
+			}
+			if (!ao_play(odev, (char *)buf, sizeof(buf)))
+				errx(1, "cannot play test audio");
+		}
+	}
+
+	return (0);
+}

helper.h

@@ -0,0 +1,16 @@
+/*
+ * helper.h
+ *
+ *  Created on: 21.04.2015
+ *      Author: sebastian
+ */
+
+#ifndef HELPER_H_
+#define HELPER_H_
+
+#include <stdint.h>
+#include <ao/ao.h>
+
+extern ao_device * open_output(int driver_id, ao_option *dev_opts, int bits, int channels, int sample_rate);
+extern int test_audio_out(int driver_id, ao_option *dev_opts);
+#endif /* HELPER_H_ */