Changes between Version 9 and Version 10 of MEDIA_ENGINE_IMPL_MAIN_R3

Timestamp:

08/31/09 16:20:12 (16 years ago)

Author:

stefan

Comment:

--

MEDIA_ENGINE_IMPL_MAIN_R3

@@ -32 +32 @@
 
 = Design =
-^(Describe your design here.)^
+So, in order to make audio working, we'll make Decoder C++ class which will unite functionality of video decoding that are provided in [wiki:MEDIA_ENGINE_IMPL_MAIN_R2] and audio decoding from this task.
+prototype of Decoder.h :
+
+{{{
+#ifndef DECODER_H_
+#define DECODER_H_
+
+class Decoder {
+public:
+    Decoder();
+    virtual ~Decoder();
+
+    Code open();
+    void close();
+    int seek(int time);
+    bool readFrame();
+    int* decodeFrame();
+    int getWidth() const;
+    int getHeight() const;
+    int getLinesize() const;
+    int getDuration() const;
+
+    bool isOpen();
+
+    bool readAudioFrame();
+    int* decodeAudioFrame(int*);
+    int* saveAudioBuffer(uint8_t*, int);
+
+private:
+    bool is_open;
+    bool is_closed;
+
+    AVFormatContext *pFormatContext;
+    AVCodecContext *pCodecCtx;
+    int videoStream, audiostream;
+    uint8_t *buffer, *audio_buf;
+    AVFrame *pFrame, *pFrameRGB;
+    AVCodec *pCodec, *aCodec;
+    PixelFormat pixFMT;
+
+    int* saveFrame(AVFrame *pFrame, int width, int height);
+
+    AVPacket packet;
+    int buf_size;
+};
+
+#endif /* DECODER_H_ */
+}}}
+
+
+
+A decode method for the audio stream in this class should be provided:
+prototype:
+{{{
+int* AudioPlayer::decodeAudioFrame(int* size) {
+
+    uint8_t* audio_pkt_data = NULL;
+    int audio_pkt_size = 0;
+
+    int len1;
+    
+    audio_pkt_data = packet.data;
+
+    audio_pkt_size = packet.size;
+    audio_buf =(uint8_t*) av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE*sizeof(uint8_t));
+    buf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
+    
+    packet.data =(uint8_t*) av_malloc((audio_pkt_size + FF_INPUT_BUFFER_PADDING_SIZE)*sizeof(uint8_t));
+    memcpy(packet.data, audio_pkt_data, audio_pkt_size);
+    while (audio_pkt_size > 0) {
+        int data_size = buf_size;
+        //fprintf(stderr,"decodeAudioFrame: Trying to decode packet!\n");
+        //fprintf(stderr,"decodeAudioFrame: data_size before decode: %d.\n",data_size);
+        len1 = avcodec_decode_audio3(aCodecCtx, (int16_t *) audio_buf,
+                &data_size, &packet);
+        //fprintf(stderr,"decodeAudioFrame: Number of bytes decoded: %d.\n",len1);
+        //fprintf(stderr,"decodeAudioFrame: data_size after decode: %d.\n",data_size);
+        if (len1 < 0) {
+            //fprintf(stderr,"decodeAudioFrame: ERROR decoding!\n");
+            /* if error, skip frame */
+            audio_pkt_size = 0;
+            break;
+        }
+        //fprintf(stderr,"decodeAudioFrame: Sound probably decoded...\n");
+        audio_pkt_data += len1;
+        audio_pkt_size -= len1;
+        if (data_size <= 0) {
+            //fprintf(stderr,"decodeAudioFrame: SHOULDN'T GET HERE!\n");
+            continue;
+        }/* We have data, return it and come back for more later */
+        size = &data_size;
+        //fprintf(stderr,"decodeAudioFrame: Gets before saving buffer with size: %d\n", *size);
+        return saveAudioBuffer(audio_buf, data_size);
+    }
+}}}
 
 = Implementation =