/***************************************************************************
*             __________               __   ___.
*   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
*   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
*   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
*   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
*                     \/            \/     \/    \/            \/
* $Id$
*
* Plugin for video playback
* Reads raw image data + audio data from a file
* !!!!!!!!!! Code Police free zone !!!!!!!!!!
*
* Copyright (C) 2003-2004 Jörg Hohensohn aka [IDC]Dragon
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/


/****************** imports ******************/

#include "plugin.h"
#include "sh7034.h"
#include "system.h"
#include "../apps/recorder/widgets.h" // not in search path, booh

#ifndef SIMULATOR // not for simulator by now
#ifdef HAVE_LCD_BITMAP // and definitely not for the Player, haha

/****************** constants ******************/

#define INT_MAX ((int)(~(unsigned)0 >> 1))
#define INT_MIN (-INT_MAX-1)

#define SCREENSIZE (LCD_WIDTH*LCD_HEIGHT/8) // in bytes
#define FPS 68 // default fps for headerless (old video-only) file
#define MAX_ACC 20 // maximum FF/FR speedup
#define FF_TICKS 3000; // experimentally found nice

// trigger levels, we need about 80 kB/sec
#define SPINUP_INIT 5000 // from what level on to refill, in milliseconds
#define SPINUP_SAFETY 700 // how much on top of the measured spinup time
#define CHUNK (1024*32) // read size


/****************** prototypes ******************/
void timer4_isr(void); // IMIA4 ISR
int check_button(void); // determine next relative frame


/****************** data types ******************/

// plugins don't introduce headers, so structs are repeated from rvf_format.h

#define HEADER_MAGIC 0x52564668 // "RVFh" at file start 
#define AUDIO_MAGIC  0x41756446 // "AudF" for each audio block
#define FILEVERSION  100 // 1.00

// format type definitions
#define VIDEOFORMAT_NO_VIDEO       0
#define VIDEOFORMAT_RAW            1
#define AUDIOFORMAT_NO_AUDIO       0
#define AUDIOFORMAT_MP3            1
#define AUDIOFORMAT_MP3_BITSWAPPED 2

// bit flags
#define FLAG_LOOP 0x00000001 // loop the playback, e.g. for stills

typedef struct // contains whatever might be useful to the player
{
    // general info (16 entries = 64 byte)
    unsigned long magic; // HEADER_MAGIC
    unsigned long version; // file version
    unsigned long flags; // combination of FLAG_xx
    unsigned long blocksize; // how many bytes per block (=video frame)
    unsigned long bps_average; // bits per second of the whole stream
    unsigned long bps_peak; // max. of above (audio may be VBR)
    unsigned long resume_pos; // file position to resume to
    unsigned long reserved[9]; // reserved, should be zero

    // video info (16 entries = 64 byte)
    unsigned long video_format; // one of VIDEOFORMAT_xxx
    unsigned long video_1st_frame; // byte position of first video frame
    unsigned long video_duration; // total length of video part, in ms
    unsigned long video_payload_size; // total amount of video data, in bytes
    unsigned long video_bitrate; // derived from resolution and frame time, in bps
    unsigned long video_frametime; // frame interval in 11.0592 MHz clocks
    long video_preroll; // video is how much ahead, in 11.0592 MHz clocks
    unsigned long video_width; // in pixels
    unsigned long video_height; // in pixels
    unsigned long video_reserved[7]; // reserved, should be zero

    // audio info (16 entries = 64 byte)
    unsigned long audio_format; // one of AUDIOFORMAT_xxx
    unsigned long audio_1st_frame; // byte position of first video frame
    unsigned long audio_duration; // total length of audio part, in ms
    unsigned long audio_payload_size; // total amount of audio data, in bytes
    unsigned long audio_avg_bitrate; // average audio bitrate, in bits per second
    unsigned long audio_peak_bitrate; // maximum bitrate
    unsigned long audio_headersize; // offset to payload in audio frames
    long audio_min_associated; // minimum offset to video frame, in bytes
    long audio_max_associated; // maximum offset to video frame, in bytes
    unsigned long audio_reserved[7]; // reserved, should be zero

   // more to come... ?

    // Note: padding up to 'blocksize' with zero following this header
} tFileHeader;

typedef struct // the little header for all audio blocks
{
    unsigned long magic; // AUDIO_MAGIC indicates an audio block
	unsigned char previous_block; // previous how many blocks backwards
    unsigned char next_block; // next how many blocks forward
	short associated_video; // offset to block with corresponding video
    unsigned short frame_start; // offset to first frame starting in this block
    unsigned short frame_end; // offset to behind last frame ending in this block
} tAudioFrameHeader;



/****************** globals ******************/

static struct plugin_api* rb; /* here is a global api struct pointer */
static char gPrint[32]; /* a global printf buffer, saves stack */


// playstate
static struct 
{
    enum 
    {
        paused,
        playing,
    } state;
    bool bAudioUnderrun;
    bool bVideoUnderrun;
    bool bHasAudio;
    bool bHasVideo;
    int nTimeOSD; // OSD should stay for this many frames
    bool bDirtyOSD; // OSD needs redraw
    bool bRefilling; // set if refilling buffer
    bool bSeeking;
    int nSeekAcc; // accelleration value for seek
    int nSeekPos; // current file position for seek
    bool bDiskSleep; // disk is suspended
} gPlay;

// buffer information
static struct
{
    int bufsize;
    int granularity; // common multiple of block and sector size
    unsigned char* pBufStart; // start of ring buffer
    unsigned char* pBufEnd; // end of ring buffer
    unsigned char* pOSD; // OSD memory (112 bytes for 112*8 pixels)

    int vidcount; // how many video blocks are known in a row
    unsigned char* pBufFill; // write pointer for disk, owned by main task
    unsigned char* pReadVideo; // video readout, maintained by timer ISR
    unsigned char* pReadAudio; // audio readout, maintained by demand ISR
    bool bEOF; // flag for end of file
    int low_water; // reload threshold 
    int high_water; // end of reload threshold
    int spinup_safety; // safety margin when recalculating low_water
    int nReadChunk; // how much data for normal buffer fill
    int nSeekChunk; // how much data while seeking
} gBuf;

// statistics
static struct
{
    int minAudioAvail;
    int minVideoAvail;
    int nAudioUnderruns;
    int nVideoUnderruns;
    long minSpinup;
    long maxSpinup;
} gStats;

tFileHeader gFileHdr; // file header

/****************** implementation ******************/

// tool function: return how much playable audio/video is left
int Available(unsigned char* pSnapshot)
{
    if (pSnapshot <= gBuf.pBufFill)
        return gBuf.pBufFill - pSnapshot;
    else
        return gBuf.bufsize - (pSnapshot - gBuf.pBufFill);
}

// debug function to draw buffer indicators
void DrawBuf(void)
{
    int fill, video, audio;

    rb->memset(gBuf.pOSD, 0x10, LCD_WIDTH); // draw line
    gBuf.pOSD[0] = gBuf.pOSD[LCD_WIDTH-1] = 0xFE; // ends

    // calculate new tick positions
    fill = 1 + ((gBuf.pBufFill - gBuf.pBufStart) * (LCD_WIDTH-2)) / gBuf.bufsize;
    video = 1 + ((gBuf.pReadVideo - gBuf.pBufStart) * (LCD_WIDTH-2)) / gBuf.bufsize;
    audio = 1 + ((gBuf.pReadAudio - gBuf.pBufStart) * (LCD_WIDTH-2)) / gBuf.bufsize;

    gBuf.pOSD[fill] |= 0x20; // below the line, two pixels
    gBuf.pOSD[video] |= 0x08; // one above
    gBuf.pOSD[audio] |= 0x04; // two above

    if (gPlay.state == paused) // we have to draw ourselves
        rb->lcd_update_rect(0, LCD_HEIGHT-8, LCD_WIDTH, 8);
    else
        gPlay.bDirtyOSD = true; // redraw it with next timer IRQ
}


// helper function to draw a position indicator
void DrawPosition(int pos, int total)
{
    int w,h;
    int sec; // estimated seconds


    /* print the estimated position */   
    sec = pos / (gFileHdr.bps_average/8);
    if (sec < 100*60) /* fits into mm:ss format */
        rb->snprintf(gPrint, sizeof(gPrint), "%02d:%02dm", sec/60, sec%60);
    else /* a very long clip, hh:mm format */
        rb->snprintf(gPrint, sizeof(gPrint), "%02d:%02dh", sec/3600, (sec/60)%60);
    rb->lcd_puts(0, 7, gPrint);

    /* draw a slider over the rest of the line */
    rb->lcd_getstringsize(gPrint, &w, &h);
    w++;
    rb->scrollbar(w, LCD_HEIGHT-7, LCD_WIDTH-w, 7, total, 0, pos, HORIZONTAL);

    if (gPlay.state == paused) // we have to draw ourselves
        rb->lcd_update_rect(0, LCD_HEIGHT-8, LCD_WIDTH, 8);
    else // let the display time do it
    {
        gPlay.nTimeOSD = 70;
        gPlay.bDirtyOSD = true; // redraw it with next timer IRQ
    }
}


// helper function to change the volume by a certain amount, +/-
void ChangeVolume(int delta)
{
    int vol = rb->global_settings->volume + delta;

    if (vol > 100) vol = 100;
    else if (vol < 0) vol = 0;
    if (vol != rb->global_settings->volume)
    {
        rb->mpeg_sound_set(SOUND_VOLUME, vol);
        rb->global_settings->volume = vol;
        rb->snprintf(gPrint, sizeof(gPrint), "Vol: %d", vol);
        rb->lcd_puts(0, 7, gPrint);
        if (gPlay.state == paused) // we have to draw ourselves
            rb->lcd_update_rect(0, LCD_HEIGHT-8, LCD_WIDTH, 8);
        else // let the display time do it
        {
            gPlay.nTimeOSD = 50; // display it for 50 frames
            gPlay.bDirtyOSD = true; // let the refresh copy it to LCD
        }
    }
}


// helper function to change the LCD contrast by a certain amount, +/-
void ChangeContrast(int delta)
{
    static int mycontrast = -1; /* the "permanent" value while running */
    int contrast; /* updated value */

    if (mycontrast == -1)
        mycontrast = rb->global_settings->contrast;

    contrast = mycontrast + delta;
    if (contrast > 63) contrast = 63;
    else if (contrast < 5) contrast = 5;
    if (contrast != mycontrast)
    {
        rb->lcd_set_contrast(contrast);
        mycontrast = contrast;
        rb->snprintf(gPrint, sizeof(gPrint), "Contrast: %d", contrast);
        rb->lcd_puts(0, 7, gPrint);
        if (gPlay.state == paused) // we have to draw ourselves
            rb->lcd_update_rect(0, LCD_HEIGHT-8, LCD_WIDTH, 8);
        else // let the display time do it
        {
            gPlay.nTimeOSD = 50; // display it for 50 frames
            gPlay.bDirtyOSD = true; // let the refresh copy it to LCD
        }
    }
}


// sync the video to the current audio
void SyncVideo(void)
{
    tAudioFrameHeader* pAudioBuf;

    pAudioBuf = (tAudioFrameHeader*)(gBuf.pReadAudio);
    if (pAudioBuf->magic == AUDIO_MAGIC)
    {
        gBuf.vidcount = 0; // nothing known
        // sync the video position
        gBuf.pReadVideo = gBuf.pReadAudio + 
            (long)pAudioBuf->associated_video * (long)gFileHdr.blocksize;
    
        // handle possible wrap
        if (gBuf.pReadVideo >= gBuf.pBufEnd)
            gBuf.pReadVideo -= gBuf.bufsize;
        else if (gBuf.pReadVideo < gBuf.pBufStart)
            gBuf.pReadVideo += gBuf.bufsize;
    }
}


// timer interrupt handler to display a frame
void timer4_isr(void)
{
    int available;
    tAudioFrameHeader* pAudioBuf;
    int height; // height to display

    // reduce height if we have OSD on
    height = gFileHdr.video_height/8;        
    if (gPlay.nTimeOSD > 0)
    {
        gPlay.nTimeOSD--;
        height = MIN(LCD_HEIGHT/8-1, height); // reserve bottom line
        if (gPlay.bDirtyOSD)
        {   // OSD to bottom line
            rb->lcd_blit(gBuf.pOSD, 0, LCD_HEIGHT/8-1, 
                LCD_WIDTH, 1, LCD_WIDTH);
            gPlay.bDirtyOSD = false;
        }
    }

    rb->lcd_blit(gBuf.pReadVideo, 0, 0, 
        gFileHdr.video_width, height, gFileHdr.video_width);

    available = Available(gBuf.pReadVideo);

    // loop to skip audio frame(s)
    while(1)
    {
        // just for the statistics
        if (!gBuf.bEOF && available < gStats.minVideoAvail)
            gStats.minVideoAvail = available;

        if (available <= (int)gFileHdr.blocksize)
        {   // no data for next frame

            if (gBuf.bEOF && (gFileHdr.flags & FLAG_LOOP))
            {   // loop now, assuming the looped clip fits in memory
                gBuf.pReadVideo = gBuf.pBufStart + gFileHdr.video_1st_frame;
                // FixMe: pReadVideo is incremented below
            }
            else
            {
                gPlay.bVideoUnderrun = true;
                rb->plugin_unregister_timer(); // disable ourselves
                return; // no data available
            }
        }
        else // normal advance for next time
        {
            gBuf.pReadVideo += gFileHdr.blocksize;
            if (gBuf.pReadVideo >= gBuf.pBufEnd)
                gBuf.pReadVideo -= gBuf.bufsize; // wraparound
            available -= gFileHdr.blocksize;
        }

        if (!gPlay.bHasAudio)
            break; // no need to skip any audio
        
        if (gBuf.vidcount)
        {   
            // we know the next is a video frame
            gBuf.vidcount--;
            break; // exit the loop
        }
        
        pAudioBuf = (tAudioFrameHeader*)(gBuf.pReadVideo);
        if (pAudioBuf->magic == AUDIO_MAGIC)
        {   // we ran into audio, can happen after seek
            gBuf.vidcount = pAudioBuf->next_block;
            if (gBuf.vidcount)
                gBuf.vidcount--; // minus the audio block
        }
    } // while
}


// ISR function to get more mp3 data
void GetMoreMp3(unsigned char** start, int* size)
{
    int available;
    int advance;

    tAudioFrameHeader* pAudioBuf = (tAudioFrameHeader*)(gBuf.pReadAudio);

    advance = pAudioBuf->next_block * gFileHdr.blocksize;

    available = Available(gBuf.pReadAudio);

    // just for the statistics
    if (!gBuf.bEOF && available < gStats.minAudioAvail)
        gStats.minAudioAvail = available;
    
    if (available < advance + (int)gFileHdr.blocksize || advance == 0)
    {
        gPlay.bAudioUnderrun = true;
        return; // no data available
    }

    gBuf.pReadAudio += advance;
    if (gBuf.pReadAudio >= gBuf.pBufEnd)
        gBuf.pReadAudio -= gBuf.bufsize; // wraparound

    *start = gBuf.pReadAudio + gFileHdr.audio_headersize;
    *size = gFileHdr.blocksize - gFileHdr.audio_headersize;
}


int WaitForButton(void)
{
    int button;
    
    do
    {
        button = rb->button_get(true);
    } while ((button & BUTTON_REL) && button != SYS_USB_CONNECTED);
    
    return button;
}


bool WantResume(int fd)
{
    int button;

    rb->lcd_puts(0, 0, "Resume to this");
    rb->lcd_puts(0, 1, "last position?");
    rb->lcd_puts(0, 2, "PLAY = yes");
    rb->lcd_puts(0, 3, "Any Other = no");
    rb->lcd_puts(0, 4, " (plays from start)");
    DrawPosition(gFileHdr.resume_pos, rb->filesize(fd));
    rb->lcd_update();

    button = WaitForButton();
    return (button == BUTTON_PLAY);
}


int SeekTo(int fd, int nPos)
{
    int read_now, got_now;

    if (gPlay.bHasAudio)
        rb->mp3_play_stop(); // stop audio ISR
    if (gPlay.bHasVideo)
        rb->plugin_unregister_timer(); // stop the timer

    rb->lseek(fd, nPos, SEEK_SET);

    gBuf.pBufFill = gBuf.pBufStart; // all empty
    gBuf.pReadVideo = gBuf.pReadAudio = gBuf.pBufStart;

    read_now = gBuf.low_water - 1; // less than low water, so loading will continue
    read_now -= read_now % gBuf.granularity; // round down to granularity
    got_now = rb->read(fd, gBuf.pBufFill, read_now);
    gBuf.bEOF = (read_now != got_now);
    gBuf.pBufFill += got_now;

    if (nPos == 0)
    {   // we seeked to the start
        if (gPlay.bHasVideo)
            gBuf.pReadVideo += gFileHdr.video_1st_frame;

        if (gPlay.bHasAudio)
            gBuf.pReadAudio += gFileHdr.audio_1st_frame;
    }
    else
    {   // we have to search for the positions
        if (gPlay.bHasAudio) // prepare audio playback, if contained
        {
            // search for audio frame
            while (((tAudioFrameHeader*)(gBuf.pReadAudio))->magic != AUDIO_MAGIC)
                gBuf.pReadAudio += gFileHdr.blocksize;
            
            if (gPlay.bHasVideo)
                SyncVideo(); // pick the right video for that
        }
    }

    // synchronous start
    gPlay.state = playing;
    if (gPlay.bHasAudio)
    {
        gPlay.bAudioUnderrun = false;
        rb->mp3_play_data(gBuf.pReadAudio + gFileHdr.audio_headersize,
                gFileHdr.blocksize - gFileHdr.audio_headersize, GetMoreMp3);
        rb->mp3_play_pause(true); // kickoff audio
    }
    if (gPlay.bHasVideo)
    {
        gPlay.bVideoUnderrun = false;
        // start display interrupt
        rb->plugin_register_timer(gFileHdr.video_frametime, 1, timer4_isr);
    }

    return 0;
}


// returns >0 if continue, =0 to stop, <0 to abort (USB)
int PlayTick(int fd)
{
    int button;
    int avail_audio = -1, avail_video = -1;
    int retval = 1;
    int filepos;

    // check buffer level
    
    if (gPlay.bHasAudio)
        avail_audio = Available(gBuf.pReadAudio);
    if (gPlay.bHasVideo)
        avail_video = Available(gBuf.pReadVideo);

    if ((gPlay.bHasAudio && avail_audio < gBuf.low_water)
     || (gPlay.bHasVideo && avail_video < gBuf.low_water))
    {
        gPlay.bRefilling = true; /* go to refill mode */
    }

    if ((!gPlay.bHasAudio || gPlay.bAudioUnderrun)
     && (!gPlay.bHasVideo || gPlay.bVideoUnderrun)
     && gBuf.bEOF)
    {
        if (gFileHdr.resume_pos)
        {   // we played til the end, clear resume position
            gFileHdr.resume_pos = 0;
            rb->lseek(fd, 0, SEEK_SET); // save resume position
            rb->write(fd, &gFileHdr, sizeof(gFileHdr));
        }
        return 0; // all expired
    }

    if (!gPlay.bRefilling || gBuf.bEOF)
    {   // nothing to do
        button = rb->button_get_w_tmo(HZ/10);
    }
    else
    {   // refill buffer
        int read_now, got_now;
        int buf_free;
        long spinup; // measure the spinup time
        
        // how much can we reload, don't fill completely, would appear empty
        buf_free = gBuf.bufsize - MAX(avail_audio, avail_video) - gBuf.high_water;
        if (buf_free < 0)
            buf_free = 0; // just for safety
        buf_free -= buf_free % gBuf.granularity; // round down to granularity

        // in one piece max. up to buffer end (wrap after that)
        read_now = MIN(buf_free, gBuf.pBufEnd - gBuf.pBufFill);

        // load piecewise, to stay responsive
        read_now = MIN(read_now, gBuf.nReadChunk);

        if (read_now == buf_free)
            gPlay.bRefilling = false; // last piece requested

        spinup = *rb->current_tick; // in case this is interesting below
        
        got_now = rb->read(fd, gBuf.pBufFill, read_now);
        if (got_now != read_now || read_now == 0)
        {
            gBuf.bEOF = true;
            gPlay.bRefilling = false;
        }

        if (gPlay.bDiskSleep) // statistics about the spinup time
        {
            spinup = *rb->current_tick - spinup;
            gPlay.bDiskSleep = false;
            if (spinup > gStats.maxSpinup)
                gStats.maxSpinup = spinup;
            if (spinup < gStats.minSpinup)
                gStats.minSpinup = spinup;

            // recalculate the low water mark from real measurements
            gBuf.low_water = (gStats.maxSpinup + gBuf.spinup_safety) 
                             * gFileHdr.bps_peak / 8 / HZ;
        }

        if (!gPlay.bRefilling 
            && rb->global_settings->disk_spindown < 20) // condition for test only
        {
            rb->ata_sleep(); // no point in leaving the disk run til timeout
            gPlay.bDiskSleep = true;
        }

        gBuf.pBufFill += got_now;
        if (gBuf.pBufFill >= gBuf.pBufEnd)
            gBuf.pBufFill = gBuf.pBufStart; // wrap

        rb->yield(); // have mercy with the other threads
        button = rb->button_get(false);
    }

    // check keypresses

    if (button != BUTTON_NONE)
    {
        filepos = rb->lseek(fd, 0, SEEK_CUR);

        if (gPlay.bHasVideo) // video position is more accurate
            filepos -= Available(gBuf.pReadVideo); // take video position
        else
            filepos -= Available(gBuf.pReadAudio); // else audio

        switch (button)
        {   // set exit conditions
        case BUTTON_OFF:
            if (gFileHdr.magic == HEADER_MAGIC // only if file has header
                && !(gFileHdr.flags & FLAG_LOOP)) // not for stills
            {
                gFileHdr.resume_pos = filepos;
                rb->lseek(fd, 0, SEEK_SET); // save resume position
                rb->write(fd, &gFileHdr, sizeof(gFileHdr));
            }
            retval = 0; // signal "stop" to caller
            break;
        case SYS_USB_CONNECTED:
            retval = -1; // signal "abort" to caller
            break;
        case BUTTON_PLAY:
            if (gPlay.bSeeking)
            {
                gPlay.bSeeking = false;
                gPlay.state = playing;
                SeekTo(fd, gPlay.nSeekPos);
            }
            else if (gPlay.state == playing)
            {
                gPlay.state = paused;
                if (gPlay.bHasAudio)
                    rb->mp3_play_pause(false); // pause audio
                if (gPlay.bHasVideo)
                    rb->plugin_unregister_timer(); // stop the timer
            }
            else if (gPlay.state == paused)
            {
                gPlay.state = playing;
                if (gPlay.bHasAudio)
                {
                    if (gPlay.bHasVideo)
                        SyncVideo();
                    rb->mp3_play_pause(true); // play audio
                }
                if (gPlay.bHasVideo)
                {   // start the video
                    rb->plugin_register_timer(
                        gFileHdr.video_frametime, 1, timer4_isr);
                }
            }
            break;
        case BUTTON_UP:
        case BUTTON_UP | BUTTON_REPEAT:
            if (gPlay.bHasAudio)
                ChangeVolume(1);
            break;
        case BUTTON_DOWN:
        case BUTTON_DOWN | BUTTON_REPEAT:
            if (gPlay.bHasAudio)
                ChangeVolume(-1);
            break;
        case BUTTON_LEFT:
        case BUTTON_LEFT | BUTTON_REPEAT:
            if (!gPlay.bSeeking) // prepare seek
            {
                gPlay.nSeekPos = filepos;
                gPlay.bSeeking = true;
                gPlay.nSeekAcc = 0;
            }
            else if (gPlay.nSeekAcc > 0) // other direction, stop sliding
                gPlay.nSeekAcc = 0;
            else
                gPlay.nSeekAcc--;
            break;
        case BUTTON_RIGHT:
        case BUTTON_RIGHT | BUTTON_REPEAT:
            if (!gPlay.bSeeking) // prepare seek
            {
                gPlay.nSeekPos = filepos;
                gPlay.bSeeking = true;
                gPlay.nSeekAcc = 0;
            }
            else if (gPlay.nSeekAcc < 0) // other direction, stop sliding
                gPlay.nSeekAcc = 0;
            else
                gPlay.nSeekAcc++;
            break;
        case BUTTON_F1: // debug key
        case BUTTON_F1 | BUTTON_REPEAT:
            DrawBuf(); // show buffer status
            gPlay.nTimeOSD = 30;
            gPlay.bDirtyOSD = true;
            break;
        case BUTTON_F2: // contrast down
        case BUTTON_F2 | BUTTON_REPEAT:
            if (gPlay.bHasVideo)
                ChangeContrast(-1);
            break;
        case BUTTON_F3: // contrast up
        case BUTTON_F3 | BUTTON_REPEAT:
            if (gPlay.bHasVideo)
                ChangeContrast(1);
            break;
        }
    } /*  if (button != BUTTON_NONE) */

    
    // handle seeking
    
    if (gPlay.bSeeking) // seeking?
    {
        if (gPlay.nSeekAcc < -MAX_ACC)
            gPlay.nSeekAcc = -MAX_ACC;
        else if (gPlay.nSeekAcc > MAX_ACC)
            gPlay.nSeekAcc = MAX_ACC;
        
        gPlay.nSeekPos += gPlay.nSeekAcc * gBuf.nSeekChunk;
        if (gPlay.nSeekPos < 0)
            gPlay.nSeekPos = 0;
        if (gPlay.nSeekPos > rb->filesize(fd) - gBuf.granularity)
        {
            gPlay.nSeekPos = rb->filesize(fd);
            gPlay.nSeekPos -= gPlay.nSeekPos % gBuf.granularity;
        }
        DrawPosition(gPlay.nSeekPos, rb->filesize(fd));
    }


    // check + recover underruns
    
    if ((gPlay.bAudioUnderrun || gPlay.bVideoUnderrun) && !gBuf.bEOF)
    {
        gBuf.spinup_safety += HZ/2; // add extra spinup time for the future
        filepos = rb->lseek(fd, 0, SEEK_CUR);

        if (gPlay.bHasVideo && gPlay.bVideoUnderrun)
        {
            gStats.nVideoUnderruns++;
            filepos -= Available(gBuf.pReadVideo); // take video position
            SeekTo(fd, filepos);
        }
        else if (gPlay.bHasAudio && gPlay.bAudioUnderrun)
        {
            gStats.nAudioUnderruns++;
            filepos -= Available(gBuf.pReadAudio); // else audio
            SeekTo(fd, filepos);
        }
    }

    return retval;
}


int main(char* filename)
{
    int file_size;
    int fd; /* file descriptor handle */
    int read_now, got_now;
    int button = 0;
    int retval;

    // try to open the file
    fd = rb->open(filename, O_RDWR);
    if (fd < 0)
        return PLUGIN_ERROR;
    file_size =  rb->filesize(fd);

    // init statistics
    rb->memset(&gStats, 0, sizeof(gStats));
    gStats.minAudioAvail = gStats.minVideoAvail = INT_MAX;
    gStats.minSpinup = INT_MAX;

    // init playback state
    rb->memset(&gPlay, 0, sizeof(gPlay));

    // init buffer
    rb->memset(&gBuf, 0, sizeof(gBuf));
    gBuf.pOSD = rb->lcd_framebuffer + LCD_WIDTH*7; // last screen line
    gBuf.pBufStart = rb->plugin_get_mp3_buffer(&gBuf.bufsize);
    //gBuf.bufsize = 1700*1024; // test, like 2MB version!!!!
    gBuf.pBufFill = gBuf.pBufStart; // all empty

    // load file header
    read_now = sizeof(gFileHdr);
    got_now = rb->read(fd, &gFileHdr, read_now);
    rb->lseek(fd, 0, SEEK_SET); // rewind to restart sector-aligned
    if (got_now != read_now)
    {
        rb->close(fd);
        return (PLUGIN_ERROR);
    }

    // check header
    if (gFileHdr.magic != HEADER_MAGIC)
    {   // old file, use default info
        rb->memset(&gFileHdr, 0, sizeof(gFileHdr));
        gFileHdr.blocksize = SCREENSIZE;
        if (file_size < SCREENSIZE * FPS) // less than a second
            gFileHdr.flags |= FLAG_LOOP;
        gFileHdr.video_format = VIDEOFORMAT_RAW;
        gFileHdr.video_width = LCD_WIDTH;
        gFileHdr.video_height = LCD_HEIGHT;
        gFileHdr.video_frametime = FREQ / FPS;
        gFileHdr.bps_peak = gFileHdr.bps_average = LCD_WIDTH * LCD_HEIGHT * FPS;
    }
    
    // continue buffer init: align the end, calc low water, read sizes
    gBuf.granularity = gFileHdr.blocksize;
    while (gBuf.granularity % 512) // common multiple of sector size
        gBuf.granularity *= 2;
    gBuf.bufsize -= gBuf.bufsize % gBuf.granularity; // round down
    gBuf.pBufEnd = gBuf.pBufStart + gBuf.bufsize;
    gBuf.low_water = SPINUP_INIT * gFileHdr.bps_peak / 8000;
    gBuf.spinup_safety = SPINUP_SAFETY * HZ / 1000; // in time ticks
    if (gFileHdr.audio_min_associated < 0)
        gBuf.high_water = 0 - gFileHdr.audio_min_associated;
    else
        gBuf.high_water = 1; // never fill buffer completely, would appear empty
    gBuf.nReadChunk = (CHUNK + gBuf.granularity - 1); // round up
    gBuf.nReadChunk -= gBuf.nReadChunk % gBuf.granularity;// and align
    gBuf.nSeekChunk = rb->filesize(fd) / FF_TICKS;
    gBuf.nSeekChunk += gBuf.granularity - 1; // round up
    gBuf.nSeekChunk -= gBuf.nSeekChunk % gBuf.granularity; // and align

    // prepare video playback, if contained
    if (gFileHdr.video_format == VIDEOFORMAT_RAW)
    {
        gPlay.bHasVideo = true;
        if (rb->global_settings->backlight_timeout > 0)
            rb->backlight_set_timeout(1); // keep the light on
    }

    // prepare audio playback, if contained
    if (gFileHdr.audio_format == AUDIOFORMAT_MP3_BITSWAPPED)
    {
        gPlay.bHasAudio = true;
    }

    // start playback by seeking to zero or resume position
    if (gFileHdr.resume_pos && WantResume(fd)) // ask the user
        SeekTo(fd, gFileHdr.resume_pos);
    else
        SeekTo(fd, 0);

    // all that's left to do is keep the buffer full
    do // the main loop
    {
        retval = PlayTick(fd);
    } while (retval > 0);

    rb->close(fd); // close the file

    if (gPlay.bHasVideo)
        rb->plugin_unregister_timer(); // stop video ISR, now I can use the display again

    if (gPlay.bHasAudio)
        rb->mp3_play_stop(); // stop audio ISR

    // restore normal backlight setting
    rb->backlight_set_timeout(rb->global_settings->backlight_timeout);

    // restore normal contrast
    rb->lcd_set_contrast(rb->global_settings->contrast);

    if (retval < 0) // aborted?
    {
        return PLUGIN_USB_CONNECTED;
    }

#ifndef DEBUG // for release compilations, only display the stats in case of error
    if (gStats.nAudioUnderruns || gStats.nVideoUnderruns)
#endif
    {
        // display statistics
        rb->lcd_clear_display();
        rb->snprintf(gPrint, sizeof(gPrint), "%d Audio Underruns", gStats.nAudioUnderruns);
        rb->lcd_puts(0, 0, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "%d Video Underruns", gStats.nVideoUnderruns);
        rb->lcd_puts(0, 1, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "%d MinAudio bytes", gStats.minAudioAvail);
        rb->lcd_puts(0, 2, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "%d MinVideo bytes", gStats.minVideoAvail);
        rb->lcd_puts(0, 3, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "MinSpinup %d.%02d", gStats.minSpinup/HZ, gStats.minSpinup%HZ);
        rb->lcd_puts(0, 4, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "MaxSpinup %d.%02d", gStats.maxSpinup/HZ, gStats.maxSpinup%HZ);
        rb->lcd_puts(0, 5, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "LowWater: %d", gBuf.low_water);
        rb->lcd_puts(0, 6, gPrint);
        rb->snprintf(gPrint, sizeof(gPrint), "HighWater: %d", gBuf.high_water);
        rb->lcd_puts(0, 7, gPrint);
 
        rb->lcd_update();
        button = WaitForButton();
    }
    return (button == SYS_USB_CONNECTED) ? PLUGIN_USB_CONNECTED : PLUGIN_OK;
}


/***************** Plugin Entry Point *****************/

enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
{
    int ret;
    /* this macro should be called as the first thing you do in the plugin.
    it test that the api version and model the plugin was compiled for
    matches the machine it is running on */
    TEST_PLUGIN_API(api);
    
    rb = api; // copy to global api pointer
    
    if (parameter == NULL)
    {
        rb->splash(HZ*2, true, "Play .rvf file!");
        return PLUGIN_ERROR;
    }

    // now go ahead and have fun!
    ret = main((char*) parameter);
    if (ret==PLUGIN_USB_CONNECTED)
        rb->usb_screen();
    return ret;
}

#endif // #ifdef HAVE_LCD_BITMAP
#endif // #ifndef SIMULATOR

