Add an example program that streams audio using ffmpeg

1 files changed, 610 insertions, 0 deletions

diff --git a/examples/alffmpeg.c b/examples/alffmpeg.c
new file mode 100644
index 00000000..13cc0efe
--- /dev/null
+++ b/examples/alffmpeg.c
@@ -0,0 +1,610 @@
+/*
+ * FFmpeg Decoder Helpers
+ *
+ * Copyright (c) 2011 by Chris Robinson <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/* This file contains routines for helping to decode audio using libavformat
+ * and libavcodec (ffmpeg). There's very little OpenAL-specific code here. */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <assert.h>
+
+#include "AL/al.h"
+#include "AL/alc.h"
+#include "AL/alext.h"
+
+#include "alhelpers.h"
+#include "alffmpeg.h"
+
+
+static size_t NextPowerOf2(size_t value)
+{
+    size_t powerOf2 = 1;
+
+    if(value)
+    {
+        value--;
+        while(value)
+        {
+            value >>= 1;
+            powerOf2 <<= 1;
+        }
+    }
+    return powerOf2;
+}
+
+
+struct MemData {
+    char *buffer;
+    size_t length;
+    size_t pos;
+};
+
+static int MemData_read(void *opaque, uint8_t *buf, int buf_size)
+{
+    struct MemData *membuf = (struct MemData*)opaque;
+    int rem = membuf->length - membuf->pos;
+
+    if(rem > buf_size)
+        rem = buf_size;
+
+    memcpy(buf, &membuf->buffer[membuf->pos], rem);
+    membuf->pos += rem;
+
+    return rem;
+}
+
+static int MemData_write(void *opaque, uint8_t *buf, int buf_size)
+{
+    struct MemData *membuf = (struct MemData*)opaque;
+    int rem = membuf->length - membuf->pos;
+
+    if(rem > buf_size)
+        rem = buf_size;
+
+    memcpy(&membuf->buffer[membuf->pos], buf, rem);
+    membuf->pos += rem;
+
+    return rem;
+}
+
+static int64_t MemData_seek(void *opaque, int64_t offset, int whence)
+{
+    struct MemData *membuf = (struct MemData*)opaque;
+
+    switch(whence)
+    {
+        case SEEK_SET:
+            if(offset < 0 || offset > membuf->length)
+                return -1;
+            membuf->pos = offset;
+            break;
+
+        case SEEK_CUR:
+            if((offset >= 0 && offset > membuf->length-membuf->pos) ||
+               (offset < 0 && offset < -membuf->pos))
+                return -1;
+            membuf->pos += offset;
+            break;
+
+        case SEEK_END:
+            if(offset > 0 || offset < -membuf->length)
+                return -1;
+            membuf->pos = membuf->length + offset;
+            break;
+
+        default:
+            return -1;
+    }
+
+    return membuf->pos;
+}
+
+
+struct PacketList {
+    AVPacket pkt;
+    struct PacketList *next;
+};
+
+struct MyStream {
+    AVCodecContext *CodecCtx;
+    int StreamIdx;
+
+    struct PacketList *Packets;
+
+    char *DecodedData;
+    size_t DecodedDataSize;
+
+    FilePtr parent;
+};
+
+struct MyFile {
+    AVFormatContext *FmtCtx;
+
+    StreamPtr *Streams;
+    size_t StreamsSize;
+
+    struct MemData membuf;
+};
+
+
+static int done_init = 0;
+
+FilePtr openAVFile(const char *fname)
+{
+    FilePtr file;
+
+    /* We need to make sure ffmpeg is initialized. Optionally silence warning
+     * output from the lib */
+    if(!done_init) {av_register_all();
+    av_log_set_level(AV_LOG_ERROR);
+    done_init = 1;}
+
+    file = (FilePtr)calloc(1, sizeof(*file));
+    if(file && avformat_open_input(&file->FmtCtx, fname, NULL, NULL) == 0)
+    {
+        /* After opening, we must search for the stream information because not
+         * all formats will have it in stream headers */
+        if(av_find_stream_info(file->FmtCtx) >= 0)
+            return file;
+        av_close_input_file(file->FmtCtx);
+    }
+
+    free(file);
+    return NULL;
+}
+
+FilePtr openAVData(const char *name, char *buffer, size_t buffer_len)
+{
+    FilePtr file;
+
+    if(!done_init) {av_register_all();
+    av_log_set_level(AV_LOG_ERROR);
+    done_init = 1;}
+
+    if(!name)
+        name = "";
+
+    file = (FilePtr)calloc(1, sizeof(*file));
+    if(file && (file->FmtCtx=avformat_alloc_context()) != NULL)
+    {
+        static const int buflen = 4096;
+
+        file->membuf.buffer = buffer;
+        file->membuf.length = buffer_len;
+        file->membuf.pos = 0;
+
+        file->FmtCtx->pb = avio_alloc_context(av_malloc(buflen), buflen, 1, &file->membuf,
+                                              MemData_read, MemData_write, MemData_seek);
+        if(file->FmtCtx->pb && avformat_open_input(&file->FmtCtx, name, NULL, NULL) == 0)
+        {
+            if(av_find_stream_info(file->FmtCtx) >= 0)
+                return file;
+        }
+        av_close_input_file(file->FmtCtx);
+    }
+
+    free(file);
+    return NULL;
+}
+
+FilePtr openAVCustom(const char *name, void *user_data,
+                     int (*read_packet)(void *user_data, uint8_t *buf, int buf_size),
+                     int (*write_packet)(void *user_data, uint8_t *buf, int buf_size),
+                     int64_t (*seek)(void *user_data, int64_t offset, int whence))
+{
+    FilePtr file;
+
+    if(!done_init) {av_register_all();
+    av_log_set_level(AV_LOG_ERROR);
+    done_init = 1;}
+
+    if(!name)
+        name = "";
+
+    file = (FilePtr)calloc(1, sizeof(*file));
+    if(file && (file->FmtCtx=avformat_alloc_context()) != NULL)
+    {
+        static const int buflen = 4096;
+
+        file->FmtCtx->pb = avio_alloc_context(av_malloc(buflen), buflen, 1, user_data,
+                                              read_packet, write_packet, seek);
+        if(file->FmtCtx->pb && avformat_open_input(&file->FmtCtx, name, NULL, NULL) == 0)
+        {
+            if(av_find_stream_info(file->FmtCtx) >= 0)
+                return file;
+        }
+        av_close_input_file(file->FmtCtx);
+    }
+
+    free(file); 
+    return NULL;
+}
+
+
+void closeAVFile(FilePtr file)
+{
+    size_t i;
+
+    if(!file) return;
+
+    for(i = 0;i < file->StreamsSize;i++)
+    {
+        StreamPtr stream = file->Streams[i];
+
+        while(stream->Packets)
+        {
+            struct PacketList *self;
+
+            self = stream->Packets;
+            stream->Packets = self->next;
+
+            av_free_packet(&self->pkt);
+            av_free(self);
+        }
+
+        avcodec_close(stream->CodecCtx);
+        av_free(stream->DecodedData);
+        free(stream);
+    }
+    free(file->Streams);
+
+    av_close_input_file(file->FmtCtx);
+    free(file);
+}
+
+
+int getAVFileInfo(FilePtr file, int *numaudiostreams)
+{
+    unsigned int i;
+    int audiocount = 0;
+
+    if(!file) return 1;
+    for(i = 0;i < file->FmtCtx->nb_streams;i++)
+    {
+        if(file->FmtCtx->streams[i]->codec->codec_type == CODEC_TYPE_AUDIO)
+            audiocount++;
+    }
+    *numaudiostreams = audiocount;
+    return 0;
+}
+
+StreamPtr getAVAudioStream(FilePtr file, int streamnum)
+{
+    unsigned int i;
+    if(!file) return NULL;
+    for(i = 0;i < file->FmtCtx->nb_streams;i++)
+    {
+        if(file->FmtCtx->streams[i]->codec->codec_type != CODEC_TYPE_AUDIO)
+            continue;
+
+        if(streamnum == 0)
+        {
+            StreamPtr stream;
+            AVCodec *codec;
+            void *temp;
+            size_t j;
+
+            /* Found the requested stream. Check if a handle to this stream
+             * already exists and return it if it does */
+            for(j = 0;j < file->StreamsSize;j++)
+            {
+                if(file->Streams[j]->StreamIdx == (int)i)
+                    return file->Streams[j];
+            }
+
+            /* Doesn't yet exist. Now allocate a new stream object and fill in
+             * its info */
+            stream = (StreamPtr)calloc(1, sizeof(*stream));
+            if(!stream) return NULL;
+
+            stream->parent = file;
+            stream->CodecCtx = file->FmtCtx->streams[i]->codec;
+            stream->StreamIdx = i;
+
+            /* Try to find the codec for the given codec ID, and open it */
+            codec = avcodec_find_decoder(stream->CodecCtx->codec_id);
+            if(!codec || avcodec_open(stream->CodecCtx, codec) < 0)
+            {
+                free(stream);
+                return NULL;
+            }
+
+            /* Allocate space for the decoded data to be stored in before it
+             * gets passed to the app */
+            stream->DecodedData = av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
+            if(!stream->DecodedData)
+            {
+                avcodec_close(stream->CodecCtx);
+                free(stream);
+                return NULL;
+            }
+
+            /* Append the new stream object to the stream list. The original
+             * pointer will remain valid if realloc fails, so we need to use
+             * another pointer to watch for errors and not leak memory */
+            temp = realloc(file->Streams, (file->StreamsSize+1) *
+                                          sizeof(*file->Streams));
+            if(!temp)
+            {
+                avcodec_close(stream->CodecCtx);
+                av_free(stream->DecodedData);
+                free(stream);
+                return NULL;
+            }
+            file->Streams = (StreamPtr*)temp;
+            file->Streams[file->StreamsSize++] = stream;
+            return stream;
+        }
+        streamnum--;
+    }
+    return NULL;
+}
+
+int getAVAudioInfo(StreamPtr stream, ALuint *rate, ALenum *channels, ALenum *type)
+{
+    if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
+        return 1;
+
+    /* Get the sample type for OpenAL given the format detected by ffmpeg. */
+    if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_U8)
+        *type = AL_UNSIGNED_BYTE;
+    else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_S16)
+        *type = AL_SHORT;
+    else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_S32)
+        *type = AL_INT;
+    else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_FLT)
+        *type = AL_FLOAT;
+    else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_DBL)
+        *type = AL_DOUBLE;
+    else
+        return 1;
+
+    /* Get the OpenAL channel configuration using the channel layout detected
+     * by ffmpeg. NOTE: some file types may not specify a channel layout. In
+     * that case, one must be guessed based on the channel count. */
+    if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_MONO)
+        *channels = AL_MONO;
+    else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_STEREO)
+        *channels = AL_STEREO;
+    else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_QUAD)
+        *channels = AL_QUAD;
+    else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_5POINT1)
+        *channels = AL_5POINT1;
+    else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_7POINT1)
+        *channels = AL_7POINT1;
+    else if(stream->CodecCtx->channel_layout == 0)
+    {
+        /* Unknown channel layout. Try to guess. */
+        if(stream->CodecCtx->channels == 1)
+            *channels = AL_MONO;
+        else if(stream->CodecCtx->channels == 2)
+            *channels = AL_STEREO;
+        else
+            return 1;
+    }
+    else
+        return 1;
+
+    *rate = stream->CodecCtx->sample_rate;
+
+    return 0;
+}
+
+
+/* Used by getAV*Data to search for more compressed data, and buffer it in the
+ * correct stream. It won't buffer data for streams that the app doesn't have a
+ * handle for. */
+static int getNextPacket(FilePtr file, int streamidx)
+{
+    struct PacketList *packet;
+
+    packet = (struct PacketList*)av_malloc(sizeof(*packet));
+    packet->next = NULL;
+
+next_packet:
+    while(av_read_frame(file->FmtCtx, &packet->pkt) >= 0)
+    {
+        StreamPtr *iter = file->Streams;
+        StreamPtr *iter_end = iter + file->StreamsSize;
+
+        /* Check each stream the user has a handle for, looking for the one
+         * this packet belongs to */
+        while(iter != iter_end)
+        {
+            if((*iter)->StreamIdx == packet->pkt.stream_index)
+            {
+                struct PacketList **last;
+
+                last = &(*iter)->Packets;
+                while(*last != NULL)
+                    last = &(*last)->next;
+
+                *last = packet;
+                if((*iter)->StreamIdx == streamidx)
+                    return 1;
+
+                packet = (struct PacketList*)av_malloc(sizeof(*packet));
+                packet->next = NULL;
+                goto next_packet;
+            }
+            iter++;
+        }
+        /* Free the packet and look for another */
+        av_free_packet(&packet->pkt);
+    }
+
+    av_free(packet);
+    return 0;
+}
+
+void *getAVAudioData(StreamPtr stream, size_t *length)
+{
+    int size;
+    int len;
+
+    if(length) *length = 0;
+
+    if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
+        return NULL;
+
+    stream->DecodedDataSize = 0;
+
+next_packet:
+    if(!stream->Packets && !getNextPacket(stream->parent, stream->StreamIdx))
+        return NULL;
+
+    /* Decode some data, and check for errors */
+    size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
+    while((len=avcodec_decode_audio3(stream->CodecCtx,
+                                     (int16_t*)stream->DecodedData, &size,
+                                     &stream->Packets->pkt)) == 0)
+    {
+        struct PacketList *self;
+
+        if(size > 0)
+            break;
+
+        /* Packet went unread and no data was given? Drop it and try the next,
+         * I guess... */
+        self = stream->Packets;
+        stream->Packets = self->next;
+
+        av_free_packet(&self->pkt);
+        av_free(self);
+
+        if(!stream->Packets)
+            goto next_packet;
+
+        size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
+    }
+
+    if(len < 0)
+        return NULL;
+
+    if(len < stream->Packets->pkt.size)
+    {
+        /* Move the unread data to the front and clear the end bits */
+        int remaining = stream->Packets->pkt.size - len;
+        memmove(stream->Packets->pkt.data, &stream->Packets->pkt.data[len],
+                remaining);
+        memset(&stream->Packets->pkt.data[remaining], 0,
+               stream->Packets->pkt.size - remaining);
+        stream->Packets->pkt.size -= len;
+    }
+    else
+    {
+        struct PacketList *self;
+
+        self = stream->Packets;
+        stream->Packets = self->next;
+
+        av_free_packet(&self->pkt);
+        av_free(self);
+    }
+
+    if(size == 0)
+        goto next_packet;
+
+    /* Set the output buffer size */
+    stream->DecodedDataSize = size;
+    if(length) *length = stream->DecodedDataSize;
+
+    return stream->DecodedData;
+}
+
+size_t readAVAudioData(StreamPtr stream, void *data, size_t length)
+{
+    size_t dec = 0;
+
+    if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
+        return 0;
+
+    while(dec < length)
+    {
+        /* If there's no decoded data, find some */
+        if(stream->DecodedDataSize == 0)
+        {
+            if(getAVAudioData(stream, NULL) == NULL)
+                break;
+        }
+
+        if(stream->DecodedDataSize > 0)
+        {
+            /* Get the amount of bytes remaining to be written, and clamp to
+             * the amount of decoded data we have */
+            size_t rem = length-dec;
+            if(rem > stream->DecodedDataSize)
+                rem = stream->DecodedDataSize;
+
+            /* Copy the data to the app's buffer and increment */
+            if(data != NULL)
+            {
+                memcpy(data, stream->DecodedData, rem);
+                data = (char*)data + rem;
+            }
+            dec += rem;
+
+            /* If there's any decoded data left, move it to the front of the
+             * buffer for next time */
+            if(rem < stream->DecodedDataSize)
+                memmove(stream->DecodedData, &stream->DecodedData[rem],
+                        stream->DecodedDataSize - rem);
+            stream->DecodedDataSize -= rem;
+        }
+    }
+
+    /* Return the number of bytes we were able to get */
+    return dec;
+}
+
+void *decodeAVAudioStream(StreamPtr stream, size_t *length)
+{
+    char *outbuf = NULL;
+    size_t buflen = 0;
+    void *inbuf;
+    size_t got;
+
+    *length = 0;
+    if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
+        return NULL;
+
+    while((inbuf=getAVAudioData(stream, &got)) != NULL && got > 0)
+    {
+        void *ptr;
+
+        ptr = realloc(outbuf, NextPowerOf2(buflen+got));
+        if(ptr == NULL)
+            break;
+        outbuf = ptr;
+
+        memcpy(&outbuf[buflen], inbuf, got);
+        buflen += got;
+    }
+    outbuf = realloc(outbuf, buflen);
+
+    *length = buflen;
+    return outbuf;
+}