vf_setpts.c 4.9 KB

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  1. /*
  2. * Copyright (c) 2010 Stefano Sabatini
  3. * Copyright (c) 2008 Victor Paesa
  4. *
  5. * This file is part of FFmpeg.
  6. *
  7. * FFmpeg is free software; you can redistribute it and/or
  8. * modify it under the terms of the GNU Lesser General Public
  9. * License as published by the Free Software Foundation; either
  10. * version 2.1 of the License, or (at your option) any later version.
  11. *
  12. * FFmpeg is distributed in the hope that it will be useful,
  13. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15. * Lesser General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU Lesser General Public
  18. * License along with FFmpeg; if not, write to the Free Software
  19. * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20. */
  21. /**
  22. * @file
  23. * video presentation timestamp (PTS) modification filter
  24. */
  25. /* #define DEBUG */
  26. #include "libavutil/eval.h"
  27. #include "libavutil/mathematics.h"
  28. #include "avfilter.h"
  29. static const char * const var_names[] = {
  30. "INTERLACED", ///< tell if the current frame is interlaced
  31. "N", ///< frame number (starting at zero)
  32. "POS", ///< original position in the file of the frame
  33. "PREV_INPTS", ///< previous input PTS
  34. "PREV_OUTPTS", ///< previous output PTS
  35. "PTS", ///< original pts in the file of the frame
  36. "STARTPTS", ///< PTS at start of movie
  37. "TB", ///< timebase
  38. NULL
  39. };
  40. enum var_name {
  41. VAR_INTERLACED,
  42. VAR_N,
  43. VAR_POS,
  44. VAR_PREV_INPTS,
  45. VAR_PREV_OUTPTS,
  46. VAR_PTS,
  47. VAR_STARTPTS,
  48. VAR_TB,
  49. VAR_VARS_NB
  50. };
  51. typedef struct {
  52. AVExpr *expr;
  53. double var_values[VAR_VARS_NB];
  54. } SetPTSContext;
  55. static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
  56. {
  57. SetPTSContext *setpts = ctx->priv;
  58. int ret;
  59. if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
  60. var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
  61. av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
  62. return ret;
  63. }
  64. setpts->var_values[VAR_N ] = 0.0;
  65. setpts->var_values[VAR_PREV_INPTS ] = NAN;
  66. setpts->var_values[VAR_PREV_OUTPTS] = NAN;
  67. setpts->var_values[VAR_STARTPTS ] = NAN;
  68. return 0;
  69. }
  70. static int config_input(AVFilterLink *inlink)
  71. {
  72. SetPTSContext *setpts = inlink->dst->priv;
  73. setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
  74. av_log(inlink->src, AV_LOG_INFO, "TB:%f\n", setpts->var_values[VAR_TB]);
  75. return 0;
  76. }
  77. #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
  78. #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
  79. static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
  80. {
  81. SetPTSContext *setpts = inlink->dst->priv;
  82. double d;
  83. AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
  84. if (isnan(setpts->var_values[VAR_STARTPTS]))
  85. setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
  86. setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
  87. setpts->var_values[VAR_PTS ] = TS2D(inpicref->pts);
  88. setpts->var_values[VAR_POS ] = inpicref->pos == -1 ? NAN : inpicref->pos;
  89. d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
  90. outpicref->pts = D2TS(d);
  91. #ifdef DEBUG
  92. av_log(inlink->dst, AV_LOG_DEBUG,
  93. "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
  94. (int64_t)setpts->var_values[VAR_N],
  95. (int)setpts->var_values[VAR_INTERLACED],
  96. inpicref ->pos,
  97. inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
  98. outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
  99. #endif
  100. setpts->var_values[VAR_N] += 1.0;
  101. setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
  102. setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
  103. avfilter_start_frame(inlink->dst->outputs[0], outpicref);
  104. }
  105. static av_cold void uninit(AVFilterContext *ctx)
  106. {
  107. SetPTSContext *setpts = ctx->priv;
  108. av_expr_free(setpts->expr);
  109. setpts->expr = NULL;
  110. }
  111. AVFilter avfilter_vf_setpts = {
  112. .name = "setpts",
  113. .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
  114. .init = init,
  115. .uninit = uninit,
  116. .priv_size = sizeof(SetPTSContext),
  117. .inputs = (const AVFilterPad[]) {{ .name = "default",
  118. .type = AVMEDIA_TYPE_VIDEO,
  119. .get_video_buffer = avfilter_null_get_video_buffer,
  120. .config_props = config_input,
  121. .start_frame = start_frame, },
  122. { .name = NULL }},
  123. .outputs = (const AVFilterPad[]) {{ .name = "default",
  124. .type = AVMEDIA_TYPE_VIDEO, },
  125. { .name = NULL}},
  126. };