aboutsummaryrefslogtreecommitdiffstats
path: root/Game/Code/Classes/UVideo.pas
blob: fbe3ec32374ac0049fde5823a46b7076fb8d3602 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
{##############################################################################
 #                    FFmpeg support for UltraStar deluxe                     #
 #                                                                            #
 #    Created by b1indy                                                       #
 #    based on 'An ffmpeg and SDL Tutorial' (http://www.dranger.com/ffmpeg/)  #
 #    with modifications by Jay Binks <jaybinks@gmail.com>                    #
 #                                                                            #
 # http://www.mail-archive.com/fpc-pascal@lists.freepascal.org/msg09949.html  #
 # http://www.nabble.com/file/p11795857/mpegpas01.zip                         #
 #                                                                            #
 ##############################################################################}

unit UVideo;

//{$define DebugDisplay}  // uncomment if u want to see the debug stuff
//{$define DebugFrames}
//{$define VideoBenchmark}
//{$define Info}

interface

{$IFDEF FPC}
  {$MODE Delphi}
{$ENDIF}

{$I switches.inc}

(*
  TODO: look into av_read_play
*)

// use BGR-format for accelerated colorspace conversion with swscale 
{.$DEFINE PIXEL_FMT_BGR}

implementation

uses
  SDL,
  textgl,
  avcodec,
  avformat,
  avutil,
  avio,
  rational,
  {$IFDEF UseSWScale}
  swscale,
  {$ENDIF}
  math,
  gl,
  SysUtils,
  UCommon,
  UConfig,
  ULog,
  UMusic,
  UGraphicClasses,
  UGraphic;

const
{$IFDEF PIXEL_FMT_BGR}
  PIXEL_FMT_OPENGL = GL_BGR;
  PIXEL_FMT_FFMPEG = PIX_FMT_BGR24;
{$ELSE}
  PIXEL_FMT_OPENGL = GL_RGB;
  PIXEL_FMT_FFMPEG = PIX_FMT_RGB24;
{$ENDIF}

type
  TVideoPlayback_ffmpeg = class( TInterfacedObject, IVideoPlayback )
  private
    fVideoOpened,
    fVideoPaused: Boolean;

    VideoStream: PAVStream;
    VideoStreamIndex : Integer;
    VideoFormatContext: PAVFormatContext;
    VideoCodecContext: PAVCodecContext;
    VideoCodec: PAVCodec;

    AVFrame: PAVFrame;
    AVFrameRGB: PAVFrame;
    FrameBuffer: PByte;

    {$IFDEF UseSWScale}
    SoftwareScaleContext: PSwsContext;
    {$ENDIF}

    fVideoTex: GLuint;
    TexWidth, TexHeight: Cardinal;
    ScaledVideoWidth, ScaledVideoHeight: Real;
    
    VideoAspect: Real;
    VideoTimeBase, VideoTime: Extended;
    fLoopTime: Extended;

    EOF: boolean;
    Loop: boolean;

    procedure Reset();
    function DecodeFrame(var AVPacket: TAVPacket; out pts: double): boolean;
    function FindStreamIDs( const aFormatCtx : PAVFormatContext; out aFirstVideoStream, aFirstAudioStream : integer ): boolean;
    procedure SynchronizeVideo(pFrame: PAVFrame; var pts: double);
  public
    constructor Create();
    function    GetName: String;
    procedure   Init();

    function    Open(const aFileName : string): boolean; // true if succeed
    procedure   Close;

    procedure   Play;
    procedure   Pause;
    procedure   Stop;

    procedure   SetPosition(Time: real);
    function    GetPosition: real;

    procedure   GetFrame(Time: Extended);
    procedure   DrawGL(Screen: integer);

  end;

var
  singleton_VideoFFMpeg : IVideoPlayback;



function FFMpegErrorString(Errnum: integer): string;
begin
  case Errnum of
    AVERROR_IO:      Result := 'AVERROR_IO';
    AVERROR_NUMEXPECTED: Result := 'AVERROR_NUMEXPECTED';
    AVERROR_INVALIDDATA: Result := 'AVERROR_INVALIDDATA';
    AVERROR_NOMEM:   Result := 'AVERROR_NOMEM';
    AVERROR_NOFMT:   Result := 'AVERROR_NOFMT';
    AVERROR_NOTSUPP: Result := 'AVERROR_NOTSUPP';
    AVERROR_NOENT:   Result := 'AVERROR_NOENT';
    else Result := 'AVERROR_#'+inttostr(Errnum);
  end;
end;

// These are called whenever we allocate a frame buffer.
// We use this to store the global_pts in a frame at the time it is allocated.
function PtsGetBuffer(pCodecCtx: PAVCodecContext; pFrame: PAVFrame): integer; cdecl;
var
  pts: Pint64;
  VideoPktPts: Pint64;
begin
  Result := avcodec_default_get_buffer(pCodecCtx, pFrame);
  VideoPktPts := pCodecCtx^.opaque;
  if (VideoPktPts <> nil) then
  begin
    // Note: we must copy the pts instead of passing a pointer, because the packet
    // (and with it the pts) might change before a frame is returned by av_decode_video.
    pts := av_malloc(sizeof(int64));
    pts^ := VideoPktPts^;
    pFrame^.opaque := pts;
  end;
end;

procedure PtsReleaseBuffer(pCodecCtx: PAVCodecContext; pFrame: PAVFrame); cdecl;
begin
  if (pFrame <> nil) then
    av_freep(@pFrame^.opaque);
  avcodec_default_release_buffer(pCodecCtx, pFrame);
end;


{*------------------------------------------------------------------------------
 * TVideoPlayback_ffmpeg
 *------------------------------------------------------------------------------}

function  TVideoPlayback_ffmpeg.GetName: String;
begin
  result := 'FFMpeg_Video';
end;

{
  @param(aFormatCtx is a PAVFormatContext returned from av_open_input_file )
  @param(aFirstVideoStream is an OUT value of type integer, this is the index of the video stream)
  @param(aFirstAudioStream is an OUT value of type integer, this is the index of the audio stream)
  @returns(@true on success, @false otherwise)
}
function TVideoPlayback_ffmpeg.FindStreamIDs(const aFormatCtx: PAVFormatContext; out aFirstVideoStream, aFirstAudioStream: integer): boolean;
var
  i : integer;
  st : PAVStream;
begin
  // Find the first video stream
  aFirstAudioStream := -1;
  aFirstVideoStream := -1;

  {$IFDEF DebugDisplay}
  debugwriteln('aFormatCtx.nb_streams : ' + inttostr(aFormatCtx.nb_streams));
  {$ENDIF}

  for i := 0 to aFormatCtx.nb_streams-1 do
  begin
    st := aFormatCtx.streams[i];

    if (st.codec.codec_type = CODEC_TYPE_VIDEO) and
       (aFirstVideoStream < 0) then
    begin
      aFirstVideoStream := i;
    end;

    if (st.codec.codec_type = CODEC_TYPE_AUDIO) and
       (aFirstAudioStream < 0) then
    begin
      aFirstAudioStream := i;
    end;
  end;

  // return true if either an audio- or video-stream was found
  result := (aFirstAudioStream > -1) or
            (aFirstVideoStream > -1) ;
end;

procedure TVideoPlayback_ffmpeg.SynchronizeVideo(pFrame: PAVFrame; var pts: double);
var
  FrameDelay: double;
begin
  if (pts <> 0) then
  begin
    // if we have pts, set video clock to it
    VideoTime := pts;
  end else
  begin
    // if we aren't given a pts, set it to the clock
    pts := VideoTime;
  end;
  // update the video clock
  FrameDelay := av_q2d(VideoCodecContext^.time_base);
  // if we are repeating a frame, adjust clock accordingly
  FrameDelay := FrameDelay + pFrame^.repeat_pict * (FrameDelay * 0.5);
  VideoTime := VideoTime + FrameDelay;
end;

function TVideoPlayback_ffmpeg.DecodeFrame(var AVPacket: TAVPacket; out pts: double): boolean;
var
  FrameFinished: Integer;
  VideoPktPts: int64;
  pbIOCtx: PByteIOContext;
  errnum: integer;
begin
  Result := false;
  FrameFinished := 0;

  if EOF then
    Exit;

  // read packets until we have a finished frame (or there are no more packets)
  while (FrameFinished = 0) do
  begin
    errnum := av_read_frame(VideoFormatContext, AVPacket);
    if (errnum < 0) then
    begin
      // failed to read a frame, check reason

      {$IF (LIBAVFORMAT_VERSION_MAJOR >= 52)}
      pbIOCtx := VideoFormatContext^.pb;
      {$ELSE}
      pbIOCtx := @VideoFormatContext^.pb;
      {$IFEND}

      // check for end-of-file (eof is not an error)
      if (url_feof(pbIOCtx) <> 0) then
      begin
        EOF := true;
        Exit;
      end;

      // check for errors
      if (url_ferror(pbIOCtx) <> 0) then
        Exit;

      // url_feof() does not detect an EOF for some mov-files (e.g. deluxe.mov)
      // so we have to do it this way.
      if ((VideoFormatContext^.file_size <> 0) and
          (pbIOCtx^.pos >= VideoFormatContext^.file_size)) then
      begin
        EOF := true;
        Exit;
      end;

      // no error -> wait for user input
      SDL_Delay(100);
      continue;
    end;

    // if we got a packet from the video stream, then decode it
    if (AVPacket.stream_index = VideoStreamIndex) then
    begin
      // save pts to be stored in pFrame in first call of PtsGetBuffer()
      VideoPktPts := AVPacket.pts;
      VideoCodecContext^.opaque := @VideoPktPts;

      // decode packet
      avcodec_decode_video(VideoCodecContext, AVFrame,
          frameFinished, AVPacket.data, AVPacket.size);

      // reset opaque data
      VideoCodecContext^.opaque := nil;

      // update pts
      if (AVPacket.dts <> AV_NOPTS_VALUE) then
      begin
        pts := AVPacket.dts;
      end
      else if ((AVFrame^.opaque <> nil) and
               (Pint64(AVFrame^.opaque)^ <> AV_NOPTS_VALUE)) then
      begin
        pts := Pint64(AVFrame^.opaque)^;
      end
      else
      begin
        pts := 0;
      end;
      pts := pts * av_q2d(VideoStream^.time_base);

      // synchronize on each complete frame
      if (frameFinished <> 0) then
        SynchronizeVideo(AVFrame, pts);
    end;

    // free the packet from av_read_frame
    av_free_packet( @AVPacket );
  end;

  Result := true;
end;

procedure TVideoPlayback_ffmpeg.GetFrame(Time: Extended);
var
  AVPacket: TAVPacket;
  errnum: Integer;
  myTime: Extended;
  TimeDifference: Extended;
  DropFrameCount: Integer;
  pts: double;
  i: Integer;
const
  FRAME_DROPCOUNT = 3;
begin
  if not fVideoOpened then
    Exit;

  if fVideoPaused then
    Exit;

  // current time, relative to last loop (if any)
  myTime := Time - fLoopTime;
  // time since the last frame was returned
  TimeDifference := myTime - VideoTime;

  {$IFDEF DebugDisplay}
  DebugWriteln('Time:      '+inttostr(floor(Time*1000)) + sLineBreak +
               'VideoTime: '+inttostr(floor(VideoTime*1000)) + sLineBreak +
               'TimeBase:  '+inttostr(floor(VideoTimeBase*1000)) + sLineBreak +
               'TimeDiff:  '+inttostr(floor(TimeDifference*1000)));
  {$endif}

  // check if a new frame is needed
  if (VideoTime <> 0) and (TimeDifference < VideoTimeBase) then
  begin
    {$ifdef DebugFrames}
    // frame delay debug display
    GoldenRec.Spawn(200,15,1,16,0,-1,ColoredStar,$00ff00);
    {$endif}

    {$IFDEF DebugDisplay}
    DebugWriteln('not getting new frame' + sLineBreak +
        'Time:      '+inttostr(floor(Time*1000)) + sLineBreak +
        'VideoTime: '+inttostr(floor(VideoTime*1000)) + sLineBreak +
        'TimeBase:  '+inttostr(floor(VideoTimeBase*1000)) + sLineBreak +
        'TimeDiff:  '+inttostr(floor(TimeDifference*1000)));
    {$endif}

    // we do not need a new frame now
    Exit;
  end;

  // update video-time to the next frame
  VideoTime := VideoTime + VideoTimeBase;
  TimeDifference := myTime - VideoTime;

  // check if we have to skip frames
  if (TimeDifference >= FRAME_DROPCOUNT*VideoTimeBase) then
  begin
    {$IFDEF DebugFrames}
    //frame drop debug display
    GoldenRec.Spawn(200,55,1,16,0,-1,ColoredStar,$ff0000);
    {$ENDIF}
    {$IFDEF DebugDisplay}
    DebugWriteln('skipping frames' + sLineBreak +
        'TimeBase:  '+inttostr(floor(VideoTimeBase*1000)) + sLineBreak +
        'TimeDiff:  '+inttostr(floor(TimeDifference*1000)));
    {$endif}

    // update video-time
    DropFrameCount := Trunc(TimeDifference / VideoTimeBase);
    VideoTime := VideoTime + DropFrameCount*VideoTimeBase;

    // skip half of the frames, this is much smoother than to skip all at once
    for i := 1 to DropFrameCount (*div 2*) do
      DecodeFrame(AVPacket, pts);
  end;

  {$IFDEF VideoBenchmark}
  Log.BenchmarkStart(15);
  {$ENDIF}

  if (not DecodeFrame(AVPacket, pts)) then
  begin
    if Loop then
    begin
      // Record the time we looped. This is used to keep the loops in time. otherwise they speed
      SetPosition(0);
      fLoopTime := Time;
    end;
    Exit;
  end;

  // otherwise we convert the pixeldata from YUV to RGB
  {$IFDEF UseSWScale}
  errnum := sws_scale(SoftwareScaleContext, @(AVFrame.data), @(AVFrame.linesize),
          0, VideoCodecContext^.Height,
          @(AVFrameRGB.data), @(AVFrameRGB.linesize));
  {$ELSE}
  errnum := img_convert(PAVPicture(AVFrameRGB), PIXEL_FMT_FFMPEG,
            PAVPicture(AVFrame), VideoCodecContext^.pix_fmt,
			      VideoCodecContext^.width, VideoCodecContext^.height);
  {$ENDIF}
  
  if (errnum < 0) then
  begin
    Log.LogError('Image conversion failed', 'TVideoPlayback_ffmpeg.GetFrame');
    Exit;
  end;

  {$IFDEF VideoBenchmark}
  Log.BenchmarkEnd(15);
  Log.BenchmarkStart(16);
  {$ENDIF}

  // TODO: data is not padded, so we will need to tell OpenGL.
  //   Or should we add padding with avpicture_fill? (check which one is faster)
  //glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

  glBindTexture(GL_TEXTURE_2D, fVideoTex);
  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0,
      VideoCodecContext^.width, VideoCodecContext^.height,
      PIXEL_FMT_OPENGL, GL_UNSIGNED_BYTE, AVFrameRGB^.data[0]);

  {$ifdef DebugFrames}
  //frame decode debug display
  GoldenRec.Spawn(200, 35, 1, 16, 0, -1, ColoredStar, $ffff00);
  {$endif}

  {$IFDEF VideoBenchmark}
  Log.BenchmarkEnd(16);
  Log.LogBenchmark('FFmpeg', 15);
  Log.LogBenchmark('Texture', 16);
  {$ENDIF}
end;

procedure TVideoPlayback_ffmpeg.DrawGL(Screen: integer);
var
  TexVideoRightPos, TexVideoLowerPos: Single;
  ScreenLeftPos,  ScreenRightPos: Single;
  ScreenUpperPos, ScreenLowerPos: Single;
const
  ScreenMidPosX = 400.0;
  ScreenMidPosY = 300.0;
begin
  // have a nice black background to draw on (even if there were errors opening the vid)
  if (Screen = 1) then
  begin
    glClearColor(0, 0, 0, 0);
    glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
  end;

  // exit if there's nothing to draw
  if (not fVideoOpened) then
    Exit;

  {$IFDEF VideoBenchmark}
  Log.BenchmarkStart(15);
  {$ENDIF}

  TexVideoRightPos := VideoCodecContext^.width  / TexWidth;
  TexVideoLowerPos := VideoCodecContext^.height / TexHeight;
  ScreenLeftPos  := ScreenMidPosX - ScaledVideoWidth/2;
  ScreenRightPos := ScreenMidPosX + ScaledVideoWidth/2;
  ScreenUpperPos := ScreenMidPosY - ScaledVideoHeight/2;
  ScreenLowerPos := ScreenMidPosY + ScaledVideoHeight/2;

  // we could use blending for brightness control, but do we need this?
  glDisable(GL_BLEND);

  // TODO: disable other stuff like lightning, etc. 

  glEnable(GL_TEXTURE_2D);
  glBindTexture(GL_TEXTURE_2D, fVideoTex);
  glColor3f(1, 1, 1);
  glBegin(GL_QUADS);
    // upper-left coord
    glTexCoord2f(0, 0);
    glVertex2f(ScreenLeftPos, ScreenUpperPos);
    // lower-left coord
    glTexCoord2f(0, TexVideoLowerPos);
    glVertex2f(ScreenLeftPos, ScreenLowerPos);
    // lower-right coord
    glTexCoord2f(TexVideoRightPos, TexVideoLowerPos);
    glVertex2f(ScreenRightPos, ScreenLowerPos);
    // upper-right coord
    glTexCoord2f(TexVideoRightPos, 0);
    glVertex2f(ScreenRightPos, ScreenUpperPos);
  glEnd;
  glDisable(GL_TEXTURE_2D);

  {$IFDEF VideoBenchmark}
  Log.BenchmarkEnd(15);
  Log.LogBenchmark('DrawGL', 15);
  {$ENDIF}

  {$IFDEF Info}
  if (fVideoSkipTime+VideoTime+VideoTimeBase < 0) then
  begin
    glColor4f(0.7, 1, 0.3, 1);
    SetFontStyle (1);
    SetFontItalic(False);
    SetFontSize(9);
    SetFontPos (300, 0);
    glPrint('Delay due to negative VideoGap');
    glColor4f(1, 1, 1, 1);
  end;
  {$ENDIF}

  {$IFDEF DebugFrames}
    glColor4f(0, 0, 0, 0.2);
    glbegin(GL_QUADS);
      glVertex2f(0, 0);
      glVertex2f(0, 70);
      glVertex2f(250, 70);
      glVertex2f(250, 0);
    glEnd;

    glColor4f(1, 1, 1, 1);
    SetFontStyle (1);
    SetFontItalic(False);
    SetFontSize(9);
    SetFontPos (5, 0);
    glPrint('delaying frame');
    SetFontPos (5, 20);
    glPrint('fetching frame');
    SetFontPos (5, 40);
    glPrint('dropping frame');
  {$ENDIF}
end;

constructor TVideoPlayback_ffmpeg.Create();
begin
  inherited;
  Reset();
  av_register_all();
end;

procedure TVideoPlayback_ffmpeg.Init();
begin
  glGenTextures(1, PGLuint(@fVideoTex));
end;

procedure TVideoPlayback_ffmpeg.Reset();
begin
  // close previously opened video
  Close();

  fVideoOpened       := False;
  fVideoPaused       := False;
  VideoTimeBase      := 0;
  VideoTime          := 0;
  VideoStream := nil;
  VideoFormatContext := nil;
  VideoCodecContext  := nil;
  VideoStreamIndex := -1;

  AVFrame     := nil;
  AVFrameRGB  := nil;
  FrameBuffer := nil;

  EOF := false;

  // TODO: do we really want this by default?
  Loop := true;
  fLoopTime := 0;
end;

function TVideoPlayback_ffmpeg.Open(const aFileName : string): boolean; // true if succeed
var
  errnum: Integer;
  err: GLenum;
  AudioStreamIndex: integer;

  procedure CleanOnError();
  begin
    if (VideoCodecContext <> nil) then
      avcodec_close(VideoCodecContext);
    if (VideoFormatContext <> nil) then
      av_close_input_file(VideoFormatContext);
    av_free(AVFrameRGB);
    av_free(AVFrame);
    av_free(FrameBuffer);
  end;

begin
  Result := false;

  Reset();

  errnum := av_open_input_file(VideoFormatContext, pchar( aFileName ), nil, 0, nil);
  if (errnum <> 0) then
  begin
    Log.LogError('Failed to open file "'+aFileName+'" ('+FFMpegErrorString(errnum)+')');
    Exit;
  end;

  // update video info
  if (av_find_stream_info(VideoFormatContext) < 0) then
  begin
    Log.LogError('No stream info found', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;
  Log.LogInfo('VideoStreamIndex : ' + inttostr(VideoStreamIndex), 'TVideoPlayback_ffmpeg.Open');

  // find video stream
  FindStreamIDs(VideoFormatContext, VideoStreamIndex, AudioStreamIndex);
  if (VideoStreamIndex < 0) then
  begin
    Log.LogError('No video stream found', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;

  VideoStream := VideoFormatContext^.streams[VideoStreamIndex];
  VideoCodecContext := VideoStream^.codec;

  VideoCodec := avcodec_find_decoder(VideoCodecContext^.codec_id);
  if (VideoCodec = nil) then
  begin
    Log.LogError('No matching codec found', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;

  // set debug options
  VideoCodecContext^.debug_mv := 0;
  VideoCodecContext^.debug := 0;

  // detect bug-workarounds automatically
  VideoCodecContext^.workaround_bugs := FF_BUG_AUTODETECT;
  // error resilience strategy (careful/compliant/agressive/very_aggressive)
  //VideoCodecContext^.error_resilience := FF_ER_CAREFUL; //FF_ER_COMPLIANT;
  // allow non spec compliant speedup tricks.
  //VideoCodecContext^.flags2 := VideoCodecContext^.flags2 or CODEC_FLAG2_FAST;

  errnum := avcodec_open(VideoCodecContext, VideoCodec);
  if (errnum < 0) then
  begin
    Log.LogError('No matching codec found', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;

  // register custom callbacks for pts-determination 
  VideoCodecContext^.get_buffer := PtsGetBuffer;
  VideoCodecContext^.release_buffer := PtsReleaseBuffer;

  {$ifdef DebugDisplay}
  DebugWriteln('Found a matching Codec: '+ VideoCodecContext^.Codec.Name + sLineBreak +
    sLineBreak +
    '  Width = '+inttostr(VideoCodecContext^.width) +
    ', Height='+inttostr(VideoCodecContext^.height) + sLineBreak +
    '  Aspect    : '+inttostr(VideoCodecContext^.sample_aspect_ratio.num) + '/' +
                     inttostr(VideoCodecContext^.sample_aspect_ratio.den) + sLineBreak +
    '  Framerate : '+inttostr(VideoCodecContext^.time_base.num) + '/' +
                     inttostr(VideoCodecContext^.time_base.den));
  {$endif}

  // allocate space for decoded frame and rgb frame
  AVFrame := avcodec_alloc_frame();
  AVFrameRGB := avcodec_alloc_frame();
  FrameBuffer := av_malloc(avpicture_get_size(PIXEL_FMT_FFMPEG,
      VideoCodecContext^.width, VideoCodecContext^.height));

  if ((AVFrame = nil) or (AVFrameRGB = nil) or (FrameBuffer = nil)) then
  begin
    Log.LogError('Failed to allocate buffers', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;

  // TODO: pad data for OpenGL to GL_UNPACK_ALIGNMENT
  // (otherwise video will be distorted if width/height is not a multiple of the alignment)
  errnum := avpicture_fill(PAVPicture(AVFrameRGB), FrameBuffer, PIXEL_FMT_FFMPEG,
      VideoCodecContext^.width, VideoCodecContext^.height);
  if (errnum < 0) then
  begin
    Log.LogError('avpicture_fill failed: ' + FFMpegErrorString(errnum), 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;

  // calculate some information for video display
  VideoAspect := av_q2d(VideoCodecContext^.sample_aspect_ratio);
  if (VideoAspect = 0) then
    VideoAspect := VideoCodecContext^.width /
                   VideoCodecContext^.height
  else
    VideoAspect := VideoAspect * VideoCodecContext^.width /
                                 VideoCodecContext^.height;

  ScaledVideoWidth := 800.0;
  ScaledVideoHeight := 800.0 / VideoAspect;

  VideoTimeBase := 1/av_q2d(VideoStream^.r_frame_rate);

  // hack to get reasonable timebase (for divx and others)
  if (VideoTimeBase < 0.02) then // 0.02 <-> 50 fps
  begin
    VideoTimeBase := av_q2d(VideoStream^.r_frame_rate);
    while (VideoTimeBase > 50) do
      VideoTimeBase := VideoTimeBase/10;
    VideoTimeBase := 1/VideoTimeBase;
  end;

  Log.LogInfo('VideoTimeBase: ' + floattostr(VideoTimeBase), 'TVideoPlayback_ffmpeg.Open');
  Log.LogInfo('Framerate: '+inttostr(floor(1/VideoTimeBase))+'fps', 'TVideoPlayback_ffmpeg.Open');

  {$IFDEF UseSWScale}
  // if available get a SWScale-context -> faster than the deprecated img_convert().
  // SWScale has accelerated support for PIX_FMT_RGB32/PIX_FMT_BGR24/PIX_FMT_BGR565/PIX_FMT_BGR555.
  // Note: PIX_FMT_RGB32 is a BGR- and not an RGB-format (maybe a bug)!!!
  // The BGR565-formats (GL_UNSIGNED_SHORT_5_6_5) is way too slow because of its
  // bad OpenGL support. The BGR formats have MMX(2) implementations but no speed-up
  // could be observed in comparison to the RGB versions.
  SoftwareScaleContext := sws_getContext(
      VideoCodecContext^.width, VideoCodecContext^.height,
      integer(VideoCodecContext^.pix_fmt),
      VideoCodecContext^.width, VideoCodecContext^.height,
      integer(PIXEL_FMT_FFMPEG),
      SWS_FAST_BILINEAR, nil, nil, nil);
  if (SoftwareScaleContext = nil) then
  begin
    Log.LogError('Failed to get swscale context', 'TVideoPlayback_ffmpeg.Open');
    CleanOnError();
    Exit;
  end;
  {$ENDIF}

  TexWidth   := Round(Power(2, Ceil(Log2(VideoCodecContext^.width))));
  TexHeight  := Round(Power(2, Ceil(Log2(VideoCodecContext^.height))));

  // we retrieve a texture just once with glTexImage2D and update it with glTexSubImage2D later.
  // Benefits: glTexSubImage2D is faster and supports non-power-of-two widths/height.
  glBindTexture(GL_TEXTURE_2D, fVideoTex);
  glTexEnvi(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_REPLACE);
  glTexImage2D(GL_TEXTURE_2D, 0, 3, TexWidth, TexHeight, 0,
      PIXEL_FMT_OPENGL, GL_UNSIGNED_BYTE, nil);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);


  fVideoOpened := True;

  Result := true;
end;

procedure TVideoPlayback_ffmpeg.Close;
begin
  if fVideoOpened then
  begin
    av_free(FrameBuffer);
    av_free(AVFrameRGB);
    av_free(AVFrame);

    avcodec_close(VideoCodecContext);
    av_close_input_file(VideoFormatContext);

    fVideoOpened := False;
  end;
end;

procedure TVideoPlayback_ffmpeg.Play;
begin
end;

procedure TVideoPlayback_ffmpeg.Pause;
begin
  fVideoPaused := not fVideoPaused;
end;

procedure TVideoPlayback_ffmpeg.Stop;
begin
end;

procedure TVideoPlayback_ffmpeg.SetPosition(Time: real);
var
  SeekFlags: integer;
begin
  if (Time < 0) then
    Time := 0;

  // TODO: handle loop-times
  //Time := Time mod VideoDuration;

  // backward seeking might fail without AVSEEK_FLAG_BACKWARD
  SeekFlags := AVSEEK_FLAG_ANY;
  if (Time < VideoTime) then
    SeekFlags := SeekFlags or AVSEEK_FLAG_BACKWARD;

  VideoTime := Time;
  EOF := false;

  if (av_seek_frame(VideoFormatContext, VideoStreamIndex, Floor(Time/VideoTimeBase), SeekFlags) < 0) then
  begin
    Log.LogError('av_seek_frame() failed', 'TVideoPlayback_ffmpeg.SetPosition');
  end;
end;

function  TVideoPlayback_ffmpeg.GetPosition: real;
begin
  // TODO: return video-position in seconds
  result := VideoTime;
end;

initialization
  singleton_VideoFFMpeg := TVideoPlayback_ffmpeg.create();
  AudioManager.add( singleton_VideoFFMpeg );

finalization
  AudioManager.Remove( singleton_VideoFFMpeg );

end.