wrestling with libavcodec

1 files changed, 114 insertions, 0 deletions

diff --git a/avcodec_audio_example.c b/avcodec_audio_example.c
new file mode 100644
index 0000000..236b976
--- /dev/null
+++ b/avcodec_audio_example.c
@@ -0,0 +1,114 @@
+int main(int argc, char **argv)
+{
+
+    const char* input_filename=argv[1];
+
+    //avcodec_register_all();
+    av_register_all();
+    //av_ini
+
+    AVFormatContext* container=avformat_alloc_context();
+    if(avformat_open_input(&container,input_filename,NULL,NULL)<0){
+        die("Could not open file");
+    }
+
+    if(av_find_stream_info(container)<0){
+        die("Could not find file info");
+    }
+    av_dump_format(container,0,input_filename,false);
+
+    int stream_id=-1;
+    int i;
+    for(i=0;i<container->nb_streams;i++){
+        if(container->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO){
+            stream_id=i;
+            break;
+        }
+    }
+    if(stream_id==-1){
+        die("Could not find Audio Stream");
+    }
+
+    AVDictionary *metadata=container->metadata;
+
+    AVCodecContext *ctx=container->streams[stream_id]->codec;
+    AVCodec *codec=avcodec_find_decoder(ctx->codec_id);
+
+    if(codec==NULL){
+        die("cannot find codec!");
+    }
+
+    if(avcodec_open(ctx,codec)<0){
+        die("Codec cannot be found");
+    }
+
+    //ctx=avcodec_alloc_context3(codec);
+
+    //initialize AO lib
+    ao_initialize();
+
+    int driver=ao_default_driver_id();
+
+    ao_sample_format sformat;
+    AVSampleFormat sfmt=ctx->sample_fmt;
+    if(sfmt==AV_SAMPLE_FMT_U8){
+        printf("U8\n");
+
+        sformat.bits=8;
+    }else if(sfmt==AV_SAMPLE_FMT_S16){
+        printf("S16\n");
+        sformat.bits=16;
+    }else if(sfmt==AV_SAMPLE_FMT_S32){
+        printf("S32\n");
+        sformat.bits=32;
+    }
+
+    sformat.channels=ctx->channels;
+    sformat.rate=ctx->sample_rate;
+    sformat.byte_format=AO_FMT_NATIVE;
+    sformat.matrix=0;
+
+    ao_device *adevice=ao_open_live(driver,&sformat,NULL);
+    //end of init AO LIB
+
+    AVPacket packet;
+    av_init_packet(&packet);
+
+    AVFrame *frame=avcodec_alloc_frame();
+
+
+
+    int buffer_size=AVCODEC_MAX_AUDIO_FRAME_SIZE+ FF_INPUT_BUFFER_PADDING_SIZE;;
+    uint8_t buffer[buffer_size];
+    packet.data=buffer;
+    packet.size =buffer_size;
+
+
+
+    int len;
+    int frameFinished=0;
+    while(av_read_frame(container,&packet)>=0)
+    {
+
+        if(packet.stream_index==stream_id){
+            //printf("Audio Frame read  \n");
+            int len=avcodec_decode_audio4(ctx,frame,&frameFinished,&packet);
+            //frame->
+            if(frameFinished){
+                //printf("Finished reading Frame len : %d , nb_samples:%d buffer_size:%d line size: %d \n",len,frame->nb_samples,buffer_size,frame->linesize[0]);
+                ao_play(adevice, (char*)frame->extended_data[0],frame->linesize[0] );
+            }else{
+                //printf("Not Finished\n");
+            }
+
+        }else {
+            printf("Someother packet possibly Video\n");
+        }
+
+
+    }
+
+    av_close_input_file(container);
+    ao_shutdown();
+    return 0;
+}
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