usbloadergx/source/libwiigui/gui_sound_decoder_mpg.cpp

/****************************************************************************
 * libwiigui
 *
 * Tantric 2009
 *
 * gui_sound_plugin_mpg.cpp
 *
 * by ardi 2009
 *
 * Decoder for MPEG-Audio Mpeg-1/-2 Layer I,II and III with libmad
 *
 * GUI class definitions
 ***************************************************************************/

#include <unistd.h>
#include <limits.h>
#include <asndlib.h>
#include <mad.h>
#include <string.h>
#include <new>

#include "gui_sound_decoder.h"

static inline s16 FixedToShort(mad_fixed_t Fixed)
{
    /* Clipping */
    if (Fixed >= MAD_F_ONE) return (SHRT_MAX);
    if (Fixed <= -MAD_F_ONE) return (-SHRT_MAX);

    Fixed = Fixed >> (MAD_F_FRACBITS - 15);
    return ((s16) Fixed);
}

#define ADMA_BUFFERSIZE         (8192)
#define DATABUFFER_SIZE         (32768)
// http://www.fr-an.de/fragen/v06/02_01.htm


class GuiSoundDecoderMPG: public GuiSoundDecoder
{
    protected:
        GuiSoundDecoderMPG(const u8 * snd, u32 len, bool snd_is_allocated)
        {
            sound = snd;
            length = len;
            is_allocated = snd_is_allocated;
            // Init mad-structures
            mad_stream_init(&madStream);
            mad_stream_buffer(&madStream, sound, length);
            mad_frame_init(&madFrame);
            mad_synth_init(&madSynth);
            madSynthPcmPos = 0;
            mad_timer_reset( &madTimer );
            guardBuffer = NULL;
            is_running = false;

            // decode first Frame
            if (DecodeFirstFrame())
            {
                mad_synth_finish( &madSynth );
                mad_frame_finish(&madFrame);
                mad_stream_finish(&madStream);
                throw("Stream Error");
            }
        }
    public:
        ~GuiSoundDecoderMPG()
        {
            while (is_running)
                usleep(50);
            mad_synth_finish( &madSynth );
            mad_frame_finish(&madFrame);
            mad_stream_finish(&madStream);
            delete[] guardBuffer;
            if (is_allocated) delete[] sound;
        }
        static GuiSoundDecoder *Create(const u8 * snd, u32 len, bool snd_is_allocated)
        {
            struct mad_stream madStream;
            struct mad_header madHeader;
            mad_stream_init(&madStream);
            mad_stream_buffer(&madStream, snd, len);
            mad_header_init(&madHeader);
            s32 ret = mad_header_decode(&madHeader, &madStream);
            if (ret == 0 || madStream.error == MAD_ERROR_LOSTSYNC) // LOSTSYNC in first call is ok
            {
                int i;
                for (i = 0; i < 4 && mad_header_decode(&madHeader, &madStream) == 0; i++)
                    ;
                if (i == 4)
                {
                    mad_header_finish( &madHeader );
                    mad_stream_finish(&madStream);
                    return new GuiSoundDecoderMPG(snd, len, snd_is_allocated);
                }
            } mad_header_finish( &madHeader );
            mad_stream_finish(&madStream);
            return NULL;
        }
        s32 GetFormat()
        {
            return MAD_NCHANNELS( &madFrame.header ) == 2 ? VOICE_STEREO_16BIT : VOICE_MONO_16BIT;
        }
        s32 GetSampleRate()
        {
            return madFrame.header.samplerate;
        }
        /*  Read reads data from stream to buffer
         return: >0 = readed bytes;
         0 = EOF;
         <0 = Error;
         */
        int Read(u8 * buffer, int buffer_size)
        {
            is_running = true;
            if (MAD_NCHANNELS( &madFrame.header ) == 2) // stereo
                buffer_size &= ~0x0003; // make size to a kind of 4
            else buffer_size &= ~0x0001; // make size to a kind of 2
            u8 *write_pos = buffer;
            u8 *write_end = buffer + buffer_size;

            for (;;)
            {
                for (; madSynthPcmPos < madSynth.pcm.length; ++madSynthPcmPos)
                {
                    if (write_pos >= write_end)
                    {
                        is_running = false;
                        return write_pos - buffer;
                    }
                    *((s16*) write_pos) = FixedToShort(madSynth.pcm.samples[0][madSynthPcmPos]);
                    write_pos += 2;
                    if (MAD_NCHANNELS( &madFrame.header ) == 2) // stereo
                    {
                        *((s16*) write_pos) = FixedToShort(madSynth.pcm.samples[1][madSynthPcmPos]);
                        write_pos += 2;
                    }
                }

                madStream.error = MAD_ERROR_NONE;
                if (mad_frame_decode(&madFrame, &madStream))
                {
                    if (MAD_RECOVERABLE( madStream.error ))
                    {
                        if (madStream.error != MAD_ERROR_LOSTSYNC || !guardBuffer) continue;
                    }
                    else if (madStream.error == MAD_ERROR_BUFLEN)
                    {
                        if (!guardBuffer)
                        {
                            u32 guardLen = (madStream.bufend - madStream.next_frame);
                            guardBuffer = new (std::nothrow) u8[guardLen + MAD_BUFFER_GUARD];
                            if (guardBuffer)
                            {
                                memcpy(guardBuffer, madStream.next_frame, guardLen);
                                memset(guardBuffer + guardLen, 0, MAD_BUFFER_GUARD);
                                mad_stream_buffer(&madStream, guardBuffer, guardLen + MAD_BUFFER_GUARD);
                                continue;
                            }
                        }
                    }
                    break;
                }
                mad_timer_add(&madTimer, madFrame.header.duration);
                mad_synth_frame(&madSynth, &madFrame);
                madSynthPcmPos = 0;
            }
            is_running = false;
            return write_pos - buffer;
        }
        int Rewind()
        {
            while (is_running)
                usleep(50);
            delete[] guardBuffer;
            guardBuffer = NULL;
            mad_stream_buffer(&madStream, sound, length);
            mad_synth_finish( &madSynth );
            mad_synth_init(&madSynth);
            madSynthPcmPos = 0;
            mad_timer_reset( &madTimer );
            // decode first Frame
            return DecodeFirstFrame();
        }
    private:
        int DecodeFirstFrame()
        {
            for (;;)
            {
                madStream.error = MAD_ERROR_NONE;
                if (mad_frame_decode(&madFrame, &madStream))
                {
                    if (MAD_RECOVERABLE( madStream.error ))
                        continue;
                    else return -1;
                }
                mad_timer_add(&madTimer, madFrame.header.duration);
                mad_synth_frame(&madSynth, &madFrame);
                return 0;
            }
        }
        const u8 *sound;
        u32 length;
        bool is_allocated;
        struct mad_stream madStream;
        struct mad_frame madFrame;
        struct mad_synth madSynth;
        u16 madSynthPcmPos;
        mad_timer_t madTimer;
        u8 *guardBuffer;
        bool is_running;
};
REGISTER_GUI_SOUND_DECODER( GuiSoundDecoderMPG );