text: /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * Frame multithreading support functions
   * @see doc/multithreading.txt
   */
  
  #include "config.h"
  
  #include <stdint.h>
  
  #include "avcodec.h"
  #include "internal.h"
  #include "pthread_internal.h"
  #include "thread.h"
  #include "version.h"
  
  #include "libavutil/avassert.h"
  #include "libavutil/buffer.h"
  #include "libavutil/common.h"
  #include "libavutil/cpu.h"
  #include "libavutil/frame.h"
  #include "libavutil/internal.h"
  #include "libavutil/log.h"
  #include "libavutil/mem.h"
  #include "libavutil/opt.h"
  #include "libavutil/thread.h"
  
  /**
   * Context used by codec threads and stored in their AVCodecInternal thread_ctx.
   */
  typedef struct PerThreadContext {
      struct FrameThreadContext *parent;
  
      pthread_t      thread;
      int            thread_init;
      pthread_cond_t input_cond;      ///< Used to wait for a new packet from the main thread.
      pthread_cond_t progress_cond;   ///< Used by child threads to wait for progress to change.
      pthread_cond_t output_cond;     ///< Used by the main thread to wait for frames to finish.
  
      pthread_mutex_t mutex;          ///< Mutex used to protect the contents of the PerThreadContext.
      pthread_mutex_t progress_mutex; ///< Mutex used to protect frame progress values and progress_cond.
  
      AVCodecContext *avctx;          ///< Context used to decode packets passed to this thread.
  
      AVPacket       avpkt;           ///< Input packet (for decoding) or output (for encoding).
  
      AVFrame *frame;                 ///< Output frame (for decoding) or input (for encoding).
      int     got_frame;              ///< The output of got_picture_ptr from the last avcodec_decode_video() call.
      int     result;                 ///< The result of the last codec decode/encode() call.
  
      enum {
          STATE_INPUT_READY,          ///< Set when the thread is awaiting a packet.
          STATE_SETTING_UP,           ///< Set before the codec has called ff_thread_finish_setup().
          STATE_GET_BUFFER,           /**<
                                       * Set when the codec calls get_buffer().
                                       * State is returned to STATE_SETTING_UP afterwards.
                                       */
          STATE_GET_FORMAT,           /**<
                                       * Set when the codec calls get_format().
                                       * State is returned to STATE_SETTING_UP afterwards.
                                       */
          STATE_SETUP_FINISHED        ///< Set after the codec has called ff_thread_finish_setup().
      } state;
  
      /**
       * Array of frames passed to ff_thread_release_buffer().
       * Frames are released after all threads referencing them are finished.
       */
      AVFrame *released_buffers;
      int  num_released_buffers;
      int      released_buffers_allocated;
  
      AVFrame *requested_frame;       ///< AVFrame the codec passed to get_buffer()
      int      requested_flags;       ///< flags passed to get_buffer() for requested_frame
  
      const enum AVPixelFormat *available_formats; ///< Format array for get_format()
      enum AVPixelFormat result_format;            ///< get_format() result
  } PerThreadContext;
  
  /**
   * Context stored in the client AVCodecInternal thread_ctx.
   */
  typedef struct FrameThreadContext {
      PerThreadContext *threads;     ///< The contexts for each thread.
      PerThreadContext *prev_thread; ///< The last thread submit_packet() was called on.
  
      pthread_mutex_t buffer_mutex;  ///< Mutex used to protect get/release_buffer().
  
      int next_decoding;             ///< The next context to submit a packet to.
      int next_finished;             ///< The next context to return output from.
  
      int delaying;                  /**<
                                      * Set for the first N packets, where N is the number of threads.
                                      * While it is set, ff_thread_en/decode_frame won't return any results.
                                      */
  
      int die;                       ///< Set when threads should exit.
  } FrameThreadContext;
  
  #define THREAD_SAFE_CALLBACKS(avctx) \
  ((avctx)->thread_safe_callbacks || (avctx)->get_buffer2 == avcodec_default_get_buffer2)
  
  /**
   * Codec worker thread.
   *
   * Automatically calls ff_thread_finish_setup() if the codec does
   * not provide an update_thread_context method, or if the codec returns
   * before calling it.
   */
  static attribute_align_arg void *frame_worker_thread(void *arg)
  {
      PerThreadContext *p = arg;
      FrameThreadContext *fctx = p->parent;
      AVCodecContext *avctx = p->avctx;
      const AVCodec *codec = avctx->codec;
  
      pthread_mutex_lock(&p->mutex);
      while (1) {
              while (p->state == STATE_INPUT_READY && !fctx->die)
                  pthread_cond_wait(&p->input_cond, &p->mutex);
  
          if (fctx->die) break;
  
          if (!codec->update_thread_context && THREAD_SAFE_CALLBACKS(avctx))
              ff_thread_finish_setup(avctx);
  
          av_frame_unref(p->frame);
          p->got_frame = 0;
          p->result = codec->decode(avctx, p->frame, &p->got_frame, &p->avpkt);
  
          if ((p->result < 0 || !p->got_frame) && p->frame->buf[0]) {
              if (avctx->internal->allocate_progress)
                  av_log(avctx, AV_LOG_ERROR, "A frame threaded decoder did not "
                         "free the frame on failure. This is a bug, please report it.\n");
              av_frame_unref(p->frame);
          }
  
          if (p->state == STATE_SETTING_UP) ff_thread_finish_setup(avctx);
  
          pthread_mutex_lock(&p->progress_mutex);
  #if 0 //BUFREF-FIXME
          for (i = 0; i < MAX_BUFFERS; i++)
              if (p->progress_used[i] && (p->got_frame || p->result<0 || avctx->codec_id != AV_CODEC_ID_H264)) {
                  p->progress[i][0] = INT_MAX;
                  p->progress[i][1] = INT_MAX;
              }
  #endif
          p->state = STATE_INPUT_READY;
  
          pthread_cond_broadcast(&p->progress_cond);
          pthread_cond_signal(&p->output_cond);
          pthread_mutex_unlock(&p->progress_mutex);
      }
      pthread_mutex_unlock(&p->mutex);
  
      return NULL;
  }
  
  /**
   * Update the next thread's AVCodecContext with values from the reference thread's context.
   *
   * @param dst The destination context.
   * @param src The source context.
   * @param for_user 0 if the destination is a codec thread, 1 if the destination is the user's thread
   * @return 0 on success, negative error code on failure
   */
  static int update_context_from_thread(AVCodecContext *dst, AVCodecContext *src, int for_user)
  {
      int err = 0;
  
      if (dst != src) {
          dst->time_base = src->time_base;
          dst->framerate = src->framerate;
          dst->width     = src->width;
          dst->height    = src->height;
          dst->pix_fmt   = src->pix_fmt;
  
          dst->coded_width  = src->coded_width;
          dst->coded_height = src->coded_height;
  
          dst->has_b_frames = src->has_b_frames;
          dst->idct_algo    = src->idct_algo;
  
          dst->bits_per_coded_sample = src->bits_per_coded_sample;
          dst->sample_aspect_ratio   = src->sample_aspect_ratio;
  #if FF_API_AFD
  FF_DISABLE_DEPRECATION_WARNINGS
          dst->dtg_active_format     = src->dtg_active_format;
  FF_ENABLE_DEPRECATION_WARNINGS
  #endif /* FF_API_AFD */
  
          dst->profile = src->profile;
          dst->level   = src->level;
  
          dst->bits_per_raw_sample = src->bits_per_raw_sample;
          dst->ticks_per_frame     = src->ticks_per_frame;
          dst->color_primaries     = src->color_primaries;
  
          dst->color_trc   = src->color_trc;
          dst->colorspace  = src->colorspace;
          dst->color_range = src->color_range;
          dst->chroma_sample_location = src->chroma_sample_location;
  
          dst->hwaccel = src->hwaccel;
          dst->hwaccel_context = src->hwaccel_context;
  
          dst->channels       = src->channels;
          dst->sample_rate    = src->sample_rate;
          dst->sample_fmt     = src->sample_fmt;
          dst->channel_layout = src->channel_layout;
          dst->internal->hwaccel_priv_data = src->internal->hwaccel_priv_data;
      }
  
      if (for_user) {
          dst->delay       = src->thread_count - 1;
  #if FF_API_CODED_FRAME
  FF_DISABLE_DEPRECATION_WARNINGS
          dst->coded_frame = src->coded_frame;
  FF_ENABLE_DEPRECATION_WARNINGS
  #endif
      } else {
          if (dst->codec->update_thread_context)
              err = dst->codec->update_thread_context(dst, src);
      }
  
      return err;
  }
  
  /**
   * Update the next thread's AVCodecContext with values set by the user.
   *
   * @param dst The destination context.
   * @param src The source context.
   * @return 0 on success, negative error code on failure
   */
  static int update_context_from_user(AVCodecContext *dst, AVCodecContext *src)
  {
  #define copy_fields(s, e) memcpy(&dst->s, &src->s, (char*)&dst->e - (char*)&dst->s);
      dst->flags          = src->flags;
  
      dst->draw_horiz_band= src->draw_horiz_band;
      dst->get_buffer2    = src->get_buffer2;
  
      dst->opaque   = src->opaque;
      dst->debug    = src->debug;
      dst->debug_mv = src->debug_mv;
  
      dst->slice_flags = src->slice_flags;
      dst->flags2      = src->flags2;
  
      copy_fields(skip_loop_filter, subtitle_header);
  
      dst->frame_number     = src->frame_number;
      dst->reordered_opaque = src->reordered_opaque;
      dst->thread_safe_callbacks = src->thread_safe_callbacks;
  
      if (src->slice_count && src->slice_offset) {
          if (dst->slice_count < src->slice_count) {
              int err = av_reallocp_array(&dst->slice_offset, src->slice_count,
                                          sizeof(*dst->slice_offset));
              if (err < 0)
                  return err;
          }
          memcpy(dst->slice_offset, src->slice_offset,
                 src->slice_count * sizeof(*dst->slice_offset));
      }
      dst->slice_count = src->slice_count;
      return 0;
  #undef copy_fields
  }
  
  /// Releases the buffers that this decoding thread was the last user of.
  static void release_delayed_buffers(PerThreadContext *p)
  {
      FrameThreadContext *fctx = p->parent;
  
      while (p->num_released_buffers > 0) {
          AVFrame *f;
  
          pthread_mutex_lock(&fctx->buffer_mutex);
  
          // fix extended data in case the caller screwed it up
          av_assert0(p->avctx->codec_type == AVMEDIA_TYPE_VIDEO ||
                     p->avctx->codec_type == AVMEDIA_TYPE_AUDIO);
          f = &p->released_buffers[--p->num_released_buffers];
          f->extended_data = f->data;
          av_frame_unref(f);
  
          pthread_mutex_unlock(&fctx->buffer_mutex);
      }
  }
  
  static int submit_packet(PerThreadContext *p, AVPacket *avpkt)
  {
      FrameThreadContext *fctx = p->parent;
      PerThreadContext *prev_thread = fctx->prev_thread;
      const AVCodec *codec = p->avctx->codec;
  
      if (!avpkt->size && !(codec->capabilities & AV_CODEC_CAP_DELAY))
          return 0;
  
      pthread_mutex_lock(&p->mutex);
  
      release_delayed_buffers(p);
  
      if (prev_thread) {
          int err;
          if (prev_thread->state == STATE_SETTING_UP) {
              pthread_mutex_lock(&prev_thread->progress_mutex);
              while (prev_thread->state == STATE_SETTING_UP)
                  pthread_cond_wait(&prev_thread->progress_cond, &prev_thread->progress_mutex);
              pthread_mutex_unlock(&prev_thread->progress_mutex);
          }
  
          err = update_context_from_thread(p->avctx, prev_thread->avctx, 0);
          if (err) {
              pthread_mutex_unlock(&p->mutex);
              return err;
          }
      }
  
      av_packet_unref(&p->avpkt);
      av_packet_ref(&p->avpkt, avpkt);
  
      p->state = STATE_SETTING_UP;
      pthread_cond_signal(&p->input_cond);
      pthread_mutex_unlock(&p->mutex);
  
      /*
       * If the client doesn't have a thread-safe get_buffer(),
       * then decoding threads call back to the main thread,
       * and it calls back to the client here.
       */
  
      if (!p->avctx->thread_safe_callbacks && (
           p->avctx->get_format != avcodec_default_get_format ||
           p->avctx->get_buffer2 != avcodec_default_get_buffer2)) {
          while (p->state != STATE_SETUP_FINISHED && p->state != STATE_INPUT_READY) {
              int call_done = 1;
              pthread_mutex_lock(&p->progress_mutex);
              while (p->state == STATE_SETTING_UP)
                  pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
  
              switch (p->state) {
              case STATE_GET_BUFFER:
                  p->result = ff_get_buffer(p->avctx, p->requested_frame, p->requested_flags);
                  break;
              case STATE_GET_FORMAT:
                  p->result_format = ff_get_format(p->avctx, p->available_formats);
                  break;
              default:
                  call_done = 0;
                  break;
              }
              if (call_done) {
                  p->state  = STATE_SETTING_UP;
                  pthread_cond_signal(&p->progress_cond);
              }
              pthread_mutex_unlock(&p->progress_mutex);
          }
      }
  
      fctx->prev_thread = p;
      fctx->next_decoding++;
  
      return 0;
  }
  
  int ff_thread_decode_frame(AVCodecContext *avctx,
                             AVFrame *picture, int *got_picture_ptr,
                             AVPacket *avpkt)
  {
      FrameThreadContext *fctx = avctx->internal->thread_ctx;
      int finished = fctx->next_finished;
      PerThreadContext *p;
      int err;
  
      /*
       * Submit a packet to the next decoding thread.
       */
  
      p = &fctx->threads[fctx->next_decoding];
      err = update_context_from_user(p->avctx, avctx);
      if (err) return err;
      err = submit_packet(p, avpkt);
      if (err) return err;
  
      /*
       * If we're still receiving the initial packets, don't return a frame.
       */
  
      if (fctx->next_decoding > (avctx->thread_count-1-(avctx->codec_id == AV_CODEC_ID_FFV1)))
          fctx->delaying = 0;
  
      if (fctx->delaying) {
          *got_picture_ptr=0;
          if (avpkt->size)
              return avpkt->size;
      }
  
      /*
       * Return the next available frame from the oldest thread.
       * If we're at the end of the stream, then we have to skip threads that
       * didn't output a frame, because we don't want to accidentally signal
       * EOF (avpkt->size == 0 && *got_picture_ptr == 0).
       */
  
      do {
          p = &fctx->threads[finished++];
  
          if (p->state != STATE_INPUT_READY) {
              pthread_mutex_lock(&p->progress_mutex);
              while (p->state != STATE_INPUT_READY)
                  pthread_cond_wait(&p->output_cond, &p->progress_mutex);
              pthread_mutex_unlock(&p->progress_mutex);
          }
  
          av_frame_move_ref(picture, p->frame);
          *got_picture_ptr = p->got_frame;
          picture->pkt_dts = p->avpkt.dts;
  
          if (p->result < 0)
              err = p->result;
  
          /*
           * A later call with avkpt->size == 0 may loop over all threads,
           * including this one, searching for a frame to return before being
           * stopped by the "finished != fctx->next_finished" condition.
           * Make sure we don't mistakenly return the same frame again.
           */
          p->got_frame = 0;
  
          if (finished >= avctx->thread_count) finished = 0;
      } while (!avpkt->size && !*got_picture_ptr && finished != fctx->next_finished);
  
      update_context_from_thread(avctx, p->avctx, 1);
  
      if (fctx->next_decoding >= avctx->thread_count) fctx->next_decoding = 0;
  
      fctx->next_finished = finished;
  
      /*
       * When no frame was found while flushing, but an error occurred in
       * any thread, return it instead of 0.
       * Otherwise the error can get lost.
       */
      if (!avpkt->size && !*got_picture_ptr)
          return err;
  
      /* return the size of the consumed packet if no error occurred */
      return (p->result >= 0) ? avpkt->size : p->result;
  }
  
  void ff_thread_report_progress(ThreadFrame *f, int n, int field)
  {
      PerThreadContext *p;
      volatile int *progress = f->progress ? (int*)f->progress->data : NULL;
  
      if (!progress || progress[field] >= n) return;
  
      p = f->owner->internal->thread_ctx;
  
      if (f->owner->debug&FF_DEBUG_THREADS)
          av_log(f->owner, AV_LOG_DEBUG, "%p finished %d field %d\n", progress, n, field);
  
      pthread_mutex_lock(&p->progress_mutex);
      progress[field] = n;
      pthread_cond_broadcast(&p->progress_cond);
      pthread_mutex_unlock(&p->progress_mutex);
  }
  
  void ff_thread_await_progress(ThreadFrame *f, int n, int field)
  {
      PerThreadContext *p;
      volatile int *progress = f->progress ? (int*)f->progress->data : NULL;
  
      if (!progress || progress[field] >= n) return;
  
      p = f->owner->internal->thread_ctx;
  
      if (f->owner->debug&FF_DEBUG_THREADS)
          av_log(f->owner, AV_LOG_DEBUG, "thread awaiting %d field %d from %p\n", n, field, progress);
  
      pthread_mutex_lock(&p->progress_mutex);
      while (progress[field] < n)
          pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
      pthread_mutex_unlock(&p->progress_mutex);
  }
  
  void ff_thread_finish_setup(AVCodecContext *avctx) {
      PerThreadContext *p = avctx->internal->thread_ctx;
  
      if (!(avctx->active_thread_type&FF_THREAD_FRAME)) return;
  
      if(p->state == STATE_SETUP_FINISHED){
          av_log(avctx, AV_LOG_WARNING, "Multiple ff_thread_finish_setup() calls\n");
      }
  
      pthread_mutex_lock(&p->progress_mutex);
      p->state = STATE_SETUP_FINISHED;
      pthread_cond_broadcast(&p->progress_cond);
      pthread_mutex_unlock(&p->progress_mutex);
  }
  
  /// Waits for all threads to finish.
  static void park_frame_worker_threads(FrameThreadContext *fctx, int thread_count)
  {
      int i;
  
      for (i = 0; i < thread_count; i++) {
          PerThreadContext *p = &fctx->threads[i];
  
          if (p->state != STATE_INPUT_READY) {
              pthread_mutex_lock(&p->progress_mutex);
              while (p->state != STATE_INPUT_READY)
                  pthread_cond_wait(&p->output_cond, &p->progress_mutex);
              pthread_mutex_unlock(&p->progress_mutex);
          }
          p->got_frame = 0;
      }
  }
  
  void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
  {
      FrameThreadContext *fctx = avctx->internal->thread_ctx;
      const AVCodec *codec = avctx->codec;
      int i;
  
      park_frame_worker_threads(fctx, thread_count);
  
      if (fctx->prev_thread && fctx->prev_thread != fctx->threads)
          if (update_context_from_thread(fctx->threads->avctx, fctx->prev_thread->avctx, 0) < 0) {
              av_log(avctx, AV_LOG_ERROR, "Final thread update failed\n");
              fctx->prev_thread->avctx->internal->is_copy = fctx->threads->avctx->internal->is_copy;
              fctx->threads->avctx->internal->is_copy = 1;
          }
  
      fctx->die = 1;
  
      for (i = 0; i < thread_count; i++) {
          PerThreadContext *p = &fctx->threads[i];
  
          pthread_mutex_lock(&p->mutex);
          pthread_cond_signal(&p->input_cond);
          pthread_mutex_unlock(&p->mutex);
  
          if (p->thread_init)
              pthread_join(p->thread, NULL);
          p->thread_init=0;
  
          if (codec->close && p->avctx)
              codec->close(p->avctx);
  
          release_delayed_buffers(p);
          av_frame_free(&p->frame);
      }
  
      for (i = 0; i < thread_count; i++) {
          PerThreadContext *p = &fctx->threads[i];
  
          pthread_mutex_destroy(&p->mutex);
          pthread_mutex_destroy(&p->progress_mutex);
          pthread_cond_destroy(&p->input_cond);
          pthread_cond_destroy(&p->progress_cond);
          pthread_cond_destroy(&p->output_cond);
          av_packet_unref(&p->avpkt);
          av_freep(&p->released_buffers);
  
          if (i && p->avctx) {
              av_freep(&p->avctx->priv_data);
              av_freep(&p->avctx->slice_offset);
          }
  
          if (p->avctx)
              av_freep(&p->avctx->internal);
          av_freep(&p->avctx);
      }
  
      av_freep(&fctx->threads);
      pthread_mutex_destroy(&fctx->buffer_mutex);
      av_freep(&avctx->internal->thread_ctx);
  
      if (avctx->priv_data && avctx->codec && avctx->codec->priv_class)
          av_opt_free(avctx->priv_data);
      avctx->codec = NULL;
  }
  
  int ff_frame_thread_init(AVCodecContext *avctx)
  {
      int thread_count = avctx->thread_count;
      const AVCodec *codec = avctx->codec;
      AVCodecContext *src = avctx;
      FrameThreadContext *fctx;
      int i, err = 0;
  
  #if HAVE_W32THREADS
      w32thread_init();
  #endif
  
      if (!thread_count) {
          int nb_cpus = av_cpu_count();
          if ((avctx->debug & (FF_DEBUG_VIS_QP | FF_DEBUG_VIS_MB_TYPE)) || avctx->debug_mv)
              nb_cpus = 1;
          // use number of cores + 1 as thread count if there is more than one
          if (nb_cpus > 1)
              thread_count = avctx->thread_count = FFMIN(nb_cpus + 1, MAX_AUTO_THREADS);
          else
              thread_count = avctx->thread_count = 1;
      }
  
      if (thread_count <= 1) {
          avctx->active_thread_type = 0;
          return 0;
      }
  
      avctx->internal->thread_ctx = fctx = av_mallocz(sizeof(FrameThreadContext));
      if (!fctx)
          return AVERROR(ENOMEM);
  
      fctx->threads = av_mallocz_array(thread_count, sizeof(PerThreadContext));
      if (!fctx->threads) {
          av_freep(&avctx->internal->thread_ctx);
          return AVERROR(ENOMEM);
      }
  
      pthread_mutex_init(&fctx->buffer_mutex, NULL);
      fctx->delaying = 1;
  
      for (i = 0; i < thread_count; i++) {
          AVCodecContext *copy = av_malloc(sizeof(AVCodecContext));
          PerThreadContext *p  = &fctx->threads[i];
  
          pthread_mutex_init(&p->mutex, NULL);
          pthread_mutex_init(&p->progress_mutex, NULL);
          pthread_cond_init(&p->input_cond, NULL);
          pthread_cond_init(&p->progress_cond, NULL);
          pthread_cond_init(&p->output_cond, NULL);
  
          p->frame = av_frame_alloc();
          if (!p->frame) {
              av_freep(&copy);
              err = AVERROR(ENOMEM);
              goto error;
          }
  
          p->parent = fctx;
          p->avctx  = copy;
  
          if (!copy) {
              err = AVERROR(ENOMEM);
              goto error;
          }
  
          *copy = *src;
  
          copy->internal = av_malloc(sizeof(AVCodecInternal));
          if (!copy->internal) {
              copy->priv_data = NULL;
              err = AVERROR(ENOMEM);
              goto error;
          }
          *copy->internal = *src->internal;
          copy->internal->thread_ctx = p;
          copy->internal->pkt = &p->avpkt;
  
          if (!i) {
              src = copy;
  
              if (codec->init)
                  err = codec->init(copy);
  
              update_context_from_thread(avctx, copy, 1);
          } else {
              copy->priv_data = av_malloc(codec->priv_data_size);
              if (!copy->priv_data) {
                  err = AVERROR(ENOMEM);
                  goto error;
              }
              memcpy(copy->priv_data, src->priv_data, codec->priv_data_size);
              copy->internal->is_copy = 1;
  
              if (codec->init_thread_copy)
                  err = codec->init_thread_copy(copy);
          }
  
          if (err) goto error;
  
          err = AVERROR(pthread_create(&p->thread, NULL, frame_worker_thread, p));
          p->thread_init= !err;
          if(!p->thread_init)
              goto error;
      }
  
      return 0;
  
  error:
      ff_frame_thread_free(avctx, i+1);
  
      return err;
  }
  
  void ff_thread_flush(AVCodecContext *avctx)
  {
      int i;
      FrameThreadContext *fctx = avctx->internal->thread_ctx;
  
      if (!fctx) return;
  
      park_frame_worker_threads(fctx, avctx->thread_count);
      if (fctx->prev_thread) {
          if (fctx->prev_thread != &fctx->threads[0])
              update_context_from_thread(fctx->threads[0].avctx, fctx->prev_thread->avctx, 0);
      }
  
      fctx->next_decoding = fctx->next_finished = 0;
      fctx->delaying = 1;
      fctx->prev_thread = NULL;
      for (i = 0; i < avctx->thread_count; i++) {
          PerThreadContext *p = &fctx->threads[i];
          // Make sure decode flush calls with size=0 won't return old frames
          p->got_frame = 0;
          av_frame_unref(p->frame);
  
          release_delayed_buffers(p);
  
          if (avctx->codec->flush)
              avctx->codec->flush(p->avctx);
      }
  }
  
  int ff_thread_can_start_frame(AVCodecContext *avctx)
  {
      PerThreadContext *p = avctx->internal->thread_ctx;
      if ((avctx->active_thread_type&FF_THREAD_FRAME) && p->state != STATE_SETTING_UP &&
          (avctx->codec->update_thread_context || !THREAD_SAFE_CALLBACKS(avctx))) {
          return 0;
      }
      return 1;
  }
  
  static int thread_get_buffer_internal(AVCodecContext *avctx, ThreadFrame *f, int flags)
  {
      PerThreadContext *p = avctx->internal->thread_ctx;
      int err;
  
      f->owner = avctx;
  
      ff_init_buffer_info(avctx, f->f);
  
      if (!(avctx->active_thread_type & FF_THREAD_FRAME))
          return ff_get_buffer(avctx, f->f, flags);
  
      if (p->state != STATE_SETTING_UP &&
          (avctx->codec->update_thread_context || !THREAD_SAFE_CALLBACKS(avctx))) {
          av_log(avctx, AV_LOG_ERROR, "get_buffer() cannot be called after ff_thread_finish_setup()\n");
          return -1;
      }
  
      if (avctx->internal->allocate_progress) {
          int *progress;
          f->progress = av_buffer_alloc(2 * sizeof(int));
          if (!f->progress) {
              return AVERROR(ENOMEM);
          }
          progress = (int*)f->progress->data;
  
          progress[0] = progress[1] = -1;
      }
  
      pthread_mutex_lock(&p->parent->buffer_mutex);
      if (avctx->thread_safe_callbacks ||
          avctx->get_buffer2 == avcodec_default_get_buffer2) {
          err = ff_get_buffer(avctx, f->f, flags);
      } else {
          pthread_mutex_lock(&p->progress_mutex);
          p->requested_frame = f->f;
          p->requested_flags = flags;
          p->state = STATE_GET_BUFFER;
          pthread_cond_broadcast(&p->progress_cond);
  
          while (p->state != STATE_SETTING_UP)
              pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
  
          err = p->result;
  
          pthread_mutex_unlock(&p->progress_mutex);
  
      }
      if (!THREAD_SAFE_CALLBACKS(avctx) && !avctx->codec->update_thread_context)
          ff_thread_finish_setup(avctx);
      if (err)
          av_buffer_unref(&f->progress);
  
      pthread_mutex_unlock(&p->parent->buffer_mutex);
  
      return err;
  }
  
  enum AVPixelFormat ff_thread_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
  {
      enum AVPixelFormat res;
      PerThreadContext *p = avctx->internal->thread_ctx;
      if (!(avctx->active_thread_type & FF_THREAD_FRAME) || avctx->thread_safe_callbacks ||
          avctx->get_format == avcodec_default_get_format)
          return ff_get_format(avctx, fmt);
      if (p->state != STATE_SETTING_UP) {
          av_log(avctx, AV_LOG_ERROR, "get_format() cannot be called after ff_thread_finish_setup()\n");
          return -1;
      }
      pthread_mutex_lock(&p->progress_mutex);
      p->available_formats = fmt;
      p->state = STATE_GET_FORMAT;
      pthread_cond_broadcast(&p->progress_cond);
  
      while (p->state != STATE_SETTING_UP)
          pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
  
      res = p->result_format;
  
      pthread_mutex_unlock(&p->progress_mutex);
  
      return res;
  }
  
  int ff_thread_get_buffer(AVCodecContext *avctx, ThreadFrame *f, int flags)
  {
      int ret = thread_get_buffer_internal(avctx, f, flags);
      if (ret < 0)
          av_log(avctx, AV_LOG_ERROR, "thread_get_buffer() failed\n");
      return ret;
  }
  
  void ff_thread_release_buffer(AVCodecContext *avctx, ThreadFrame *f)
  {
      PerThreadContext *p = avctx->internal->thread_ctx;
      FrameThreadContext *fctx;
      AVFrame *dst, *tmp;
      int can_direct_free = !(avctx->active_thread_type & FF_THREAD_FRAME) ||
                            avctx->thread_safe_callbacks                   ||
                            avctx->get_buffer2 == avcodec_default_get_buffer2;
  
      if (!f->f || !f->f->buf[0])
          return;
  
      if (avctx->debug & FF_DEBUG_BUFFERS)
          av_log(avctx, AV_LOG_DEBUG, "thread_release_buffer called on pic %p\n", f);
  
      av_buffer_unref(&f->progress);
      f->owner    = NULL;
  
      if (can_direct_free) {
          av_frame_unref(f->f);
          return;
      }
  
      fctx = p->parent;
      pthread_mutex_lock(&fctx->buffer_mutex);
  
      if (p->num_released_buffers + 1 >= INT_MAX / sizeof(*p->released_buffers))
          goto fail;
      tmp = av_fast_realloc(p->released_buffers, &p->released_buffers_allocated,
                            (p->num_released_buffers + 1) *
                            sizeof(*p->released_buffers));
      if (!tmp)
          goto fail;
      p->released_buffers = tmp;
  
      dst = &p->released_buffers[p->num_released_buffers];
      av_frame_move_ref(dst, f->f);
  
      p->num_released_buffers++;
  
  fail:
      pthread_mutex_unlock(&fctx->buffer_mutex);
  }
  