/*
  * MMAL Video Decoder
  * Copyright (c) 2015 Rodger Combs
  *

  * 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
  * MMAL Video Decoder
  */
 

 #include <bcm_host.h>
 #include <interface/mmal/mmal.h>

 #include <interface/mmal/mmal_parameters_video.h>

 #include <interface/mmal/util/mmal_util.h>
 #include <interface/mmal/util/mmal_util_params.h>
 #include <interface/mmal/util/mmal_default_components.h>

 #include <interface/mmal/vc/mmal_vc_api.h>

 #include <stdatomic.h>

 #include "avcodec.h"

 #include "hwaccel.h"

 #include "internal.h"
 #include "libavutil/avassert.h"
 #include "libavutil/buffer.h"
 #include "libavutil/common.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"
 #include "libavutil/log.h"
 
 typedef struct FFBufferEntry {
     AVBufferRef *ref;
     void *data;
     size_t length;
     int64_t pts, dts;
     int flags;
     struct FFBufferEntry *next;
 } FFBufferEntry;
 
 // MMAL_POOL_T destroys all of its MMAL_BUFFER_HEADER_Ts. If we want correct
 // refcounting for AVFrames, we can free the MMAL_POOL_T only after all AVFrames
 // have been unreferenced.
 typedef struct FFPoolRef {

     atomic_int refcount;

     MMAL_POOL_T *pool;
 } FFPoolRef;
 
 typedef struct FFBufferRef {
     MMAL_BUFFER_HEADER_T *buffer;
     FFPoolRef *pool;
 } FFBufferRef;
 
 typedef struct MMALDecodeContext {
     AVClass *av_class;
     int extra_buffers;

     int extra_decoder_buffers;

 
     MMAL_COMPONENT_T *decoder;
     MMAL_QUEUE_T *queue_decoded_frames;
     MMAL_POOL_T *pool_in;
     FFPoolRef *pool_out;
 
     // Waiting input packets. Because the libavcodec API requires decoding and
     // returning packets in lockstep, it can happen that queue_decoded_frames
     // contains almost all surfaces - then the decoder input queue can quickly
     // fill up and won't accept new input either. Without consuming input, the
     // libavcodec API can't return new frames, and we have a logical deadlock.
     // This is avoided by queuing such buffers here.
     FFBufferEntry *waiting_buffers, *waiting_buffers_tail;
 
     int64_t packets_sent;

     atomic_int packets_buffered;

     int64_t frames_output;
     int eos_received;
     int eos_sent;

     int extradata_sent;

     int interlaced_frame;
     int top_field_first;

 } MMALDecodeContext;
 
 // Assume decoder is guaranteed to produce output after at least this many
 // packets (where each packet contains 1 frame).
 #define MAX_DELAYED_FRAMES 16
 
 static void ffmmal_poolref_unref(FFPoolRef *ref)
 {

     if (ref &&
         atomic_fetch_add_explicit(&ref->refcount, -1, memory_order_acq_rel) == 1) {

         mmal_pool_destroy(ref->pool);
         av_free(ref);
     }
 }
 
 static void ffmmal_release_frame(void *opaque, uint8_t *data)
 {
     FFBufferRef *ref = (void *)data;
 
     mmal_buffer_header_release(ref->buffer);
     ffmmal_poolref_unref(ref->pool);
 
     av_free(ref);
 }
 
 // Setup frame with a new reference to buffer. The buffer must have been
 // allocated from the given pool.
 static int ffmmal_set_ref(AVFrame *frame, FFPoolRef *pool,
                           MMAL_BUFFER_HEADER_T *buffer)
 {
     FFBufferRef *ref = av_mallocz(sizeof(*ref));
     if (!ref)
         return AVERROR(ENOMEM);
 
     ref->pool = pool;
     ref->buffer = buffer;
 
     frame->buf[0] = av_buffer_create((void *)ref, sizeof(*ref),
                                      ffmmal_release_frame, NULL,
                                      AV_BUFFER_FLAG_READONLY);
     if (!frame->buf[0]) {
         av_free(ref);
         return AVERROR(ENOMEM);
     }
 

     atomic_fetch_add_explicit(&ref->pool->refcount, 1, memory_order_relaxed);

     mmal_buffer_header_acquire(buffer);
 
     frame->format = AV_PIX_FMT_MMAL;
     frame->data[3] = (uint8_t *)ref->buffer;
     return 0;
 }
 
 static void ffmmal_stop_decoder(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_COMPONENT_T *decoder = ctx->decoder;
     MMAL_BUFFER_HEADER_T *buffer;
 
     mmal_port_disable(decoder->input[0]);
     mmal_port_disable(decoder->output[0]);
     mmal_port_disable(decoder->control);
 
     mmal_port_flush(decoder->input[0]);
     mmal_port_flush(decoder->output[0]);
     mmal_port_flush(decoder->control);
 
     while ((buffer = mmal_queue_get(ctx->queue_decoded_frames)))
         mmal_buffer_header_release(buffer);
 
     while (ctx->waiting_buffers) {
         FFBufferEntry *buffer = ctx->waiting_buffers;
 
         ctx->waiting_buffers = buffer->next;
 

         if (buffer->flags & MMAL_BUFFER_HEADER_FLAG_FRAME_END)

             atomic_fetch_add(&ctx->packets_buffered, -1);

         av_buffer_unref(&buffer->ref);
         av_free(buffer);
     }
     ctx->waiting_buffers_tail = NULL;
 

     av_assert0(atomic_load(&ctx->packets_buffered) == 0);

     ctx->frames_output = ctx->eos_received = ctx->eos_sent = ctx->packets_sent = ctx->extradata_sent = 0;

 }
 
 static av_cold int ffmmal_close_decoder(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
 
     if (ctx->decoder)
         ffmmal_stop_decoder(avctx);
 
     mmal_component_destroy(ctx->decoder);
     ctx->decoder = NULL;
     mmal_queue_destroy(ctx->queue_decoded_frames);
     mmal_pool_destroy(ctx->pool_in);
     ffmmal_poolref_unref(ctx->pool_out);
 

     mmal_vc_deinit();
 

     return 0;
 }
 
 static void input_callback(MMAL_PORT_T *port, MMAL_BUFFER_HEADER_T *buffer)
 {

     AVCodecContext *avctx = (AVCodecContext*)port->userdata;
     MMALDecodeContext *ctx = avctx->priv_data;
 

     if (!buffer->cmd) {

         FFBufferEntry *entry = buffer->user_data;
         av_buffer_unref(&entry->ref);

         if (entry->flags & MMAL_BUFFER_HEADER_FLAG_FRAME_END)

             atomic_fetch_add(&ctx->packets_buffered, -1);

         av_free(entry);

     }
     mmal_buffer_header_release(buffer);
 }
 
 static void output_callback(MMAL_PORT_T *port, MMAL_BUFFER_HEADER_T *buffer)
 {
     AVCodecContext *avctx = (AVCodecContext*)port->userdata;
     MMALDecodeContext *ctx = avctx->priv_data;
 
     mmal_queue_put(ctx->queue_decoded_frames, buffer);
 }
 
 static void control_port_cb(MMAL_PORT_T *port, MMAL_BUFFER_HEADER_T *buffer)
 {
     AVCodecContext *avctx = (AVCodecContext*)port->userdata;
     MMAL_STATUS_T status;
 
     if (buffer->cmd == MMAL_EVENT_ERROR) {
         status = *(uint32_t *)buffer->data;
         av_log(avctx, AV_LOG_ERROR, "MMAL error %d on control port\n", (int)status);
     } else {

         av_log(avctx, AV_LOG_WARNING, "Unknown MMAL event %s on control port\n",
                av_fourcc2str(buffer->cmd));

     }
 
     mmal_buffer_header_release(buffer);
 }
 
 // Feed free output buffers to the decoder.
 static int ffmmal_fill_output_port(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_BUFFER_HEADER_T *buffer;
     MMAL_STATUS_T status;
 
     if (!ctx->pool_out)
         return AVERROR_UNKNOWN; // format change code failed with OOM previously
 
     while ((buffer = mmal_queue_get(ctx->pool_out->pool->queue))) {
         if ((status = mmal_port_send_buffer(ctx->decoder->output[0], buffer))) {
             mmal_buffer_header_release(buffer);
             av_log(avctx, AV_LOG_ERROR, "MMAL error %d when sending output buffer.\n", (int)status);
             return AVERROR_UNKNOWN;
         }
     }
 
     return 0;
 }
 
 static enum AVColorSpace ffmmal_csp_to_av_csp(MMAL_FOURCC_T fourcc)
 {
     switch (fourcc) {
     case MMAL_COLOR_SPACE_BT470_2_BG:
     case MMAL_COLOR_SPACE_BT470_2_M:
     case MMAL_COLOR_SPACE_ITUR_BT601:   return AVCOL_SPC_BT470BG;
     case MMAL_COLOR_SPACE_ITUR_BT709:   return AVCOL_SPC_BT709;
     case MMAL_COLOR_SPACE_FCC:          return AVCOL_SPC_FCC;
     case MMAL_COLOR_SPACE_SMPTE240M:    return AVCOL_SPC_SMPTE240M;
     default:                            return AVCOL_SPC_UNSPECIFIED;
     }
 }
 
 static int ffmal_update_format(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_STATUS_T status;
     int ret = 0;
     MMAL_COMPONENT_T *decoder = ctx->decoder;
     MMAL_ES_FORMAT_T *format_out = decoder->output[0]->format;

     MMAL_PARAMETER_VIDEO_INTERLACE_TYPE_T interlace_type;

 
     ffmmal_poolref_unref(ctx->pool_out);
     if (!(ctx->pool_out = av_mallocz(sizeof(*ctx->pool_out)))) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }

     atomic_init(&ctx->pool_out->refcount, 1);

 
     if (!format_out)
         goto fail;
 
     if ((status = mmal_port_parameter_set_uint32(decoder->output[0], MMAL_PARAMETER_EXTRA_BUFFERS, ctx->extra_buffers)))
         goto fail;
 

     if ((status = mmal_port_parameter_set_boolean(decoder->output[0], MMAL_PARAMETER_VIDEO_INTERPOLATE_TIMESTAMPS, 0)))
         goto fail;
 

     if (avctx->pix_fmt == AV_PIX_FMT_MMAL) {
         format_out->encoding = MMAL_ENCODING_OPAQUE;
     } else {
         format_out->encoding_variant = format_out->encoding = MMAL_ENCODING_I420;
     }
 
     if ((status = mmal_port_format_commit(decoder->output[0])))
         goto fail;
 

     interlace_type.hdr.id = MMAL_PARAMETER_VIDEO_INTERLACE_TYPE;
     interlace_type.hdr.size = sizeof(MMAL_PARAMETER_VIDEO_INTERLACE_TYPE_T);
     status = mmal_port_parameter_get(decoder->output[0], &interlace_type.hdr);
     if (status != MMAL_SUCCESS) {
         av_log(avctx, AV_LOG_ERROR, "Cannot read MMAL interlace information!\n");
     } else {
         ctx->interlaced_frame = (interlace_type.eMode != MMAL_InterlaceProgressive);
         ctx->top_field_first = (interlace_type.eMode == MMAL_InterlaceFieldsInterleavedUpperFirst);
     }
 

     if ((ret = ff_set_dimensions(avctx, format_out->es->video.crop.x + format_out->es->video.crop.width,
                                         format_out->es->video.crop.y + format_out->es->video.crop.height)) < 0)
         goto fail;
 
     if (format_out->es->video.par.num && format_out->es->video.par.den) {
         avctx->sample_aspect_ratio.num = format_out->es->video.par.num;
         avctx->sample_aspect_ratio.den = format_out->es->video.par.den;
     }

     if (format_out->es->video.frame_rate.num && format_out->es->video.frame_rate.den) {
         avctx->framerate.num = format_out->es->video.frame_rate.num;
         avctx->framerate.den = format_out->es->video.frame_rate.den;
     }

 
     avctx->colorspace = ffmmal_csp_to_av_csp(format_out->es->video.color_space);
 
     decoder->output[0]->buffer_size =
         FFMAX(decoder->output[0]->buffer_size_min, decoder->output[0]->buffer_size_recommended);
     decoder->output[0]->buffer_num =
         FFMAX(decoder->output[0]->buffer_num_min, decoder->output[0]->buffer_num_recommended) + ctx->extra_buffers;
     ctx->pool_out->pool = mmal_pool_create(decoder->output[0]->buffer_num,
                                            decoder->output[0]->buffer_size);
     if (!ctx->pool_out->pool) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     return 0;
 
 fail:
     return ret < 0 ? ret : AVERROR_UNKNOWN;
 }
 
 static av_cold int ffmmal_init_decoder(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_STATUS_T status;
     MMAL_ES_FORMAT_T *format_in;
     MMAL_COMPONENT_T *decoder;
     int ret = 0;
 
     bcm_host_init();
 

     if (mmal_vc_init()) {
         av_log(avctx, AV_LOG_ERROR, "Cannot initialize MMAL VC driver!\n");
         return AVERROR(ENOSYS);
     }
 

     if ((ret = ff_get_format(avctx, avctx->codec->pix_fmts)) < 0)
         return ret;
 
     avctx->pix_fmt = ret;
 
     if ((status = mmal_component_create(MMAL_COMPONENT_DEFAULT_VIDEO_DECODER, &ctx->decoder)))
         goto fail;
 
     decoder = ctx->decoder;
 
     format_in = decoder->input[0]->format;
     format_in->type = MMAL_ES_TYPE_VIDEO;

     switch (avctx->codec_id) {

     case AV_CODEC_ID_MPEG2VIDEO:
         format_in->encoding = MMAL_ENCODING_MP2V;
         break;
     case AV_CODEC_ID_MPEG4:
         format_in->encoding = MMAL_ENCODING_MP4V;
         break;
     case AV_CODEC_ID_VC1:
         format_in->encoding = MMAL_ENCODING_WVC1;
         break;
     case AV_CODEC_ID_H264:
     default:
         format_in->encoding = MMAL_ENCODING_H264;
         break;

     }

     format_in->es->video.width = FFALIGN(avctx->width, 32);
     format_in->es->video.height = FFALIGN(avctx->height, 16);
     format_in->es->video.crop.width = avctx->width;
     format_in->es->video.crop.height = avctx->height;
     format_in->es->video.frame_rate.num = 24000;
     format_in->es->video.frame_rate.den = 1001;
     format_in->es->video.par.num = avctx->sample_aspect_ratio.num;
     format_in->es->video.par.den = avctx->sample_aspect_ratio.den;
     format_in->flags = MMAL_ES_FORMAT_FLAG_FRAMED;
 

     av_log(avctx, AV_LOG_DEBUG, "Using MMAL %s encoding.\n",
            av_fourcc2str(format_in->encoding));

 #if HAVE_MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS

     if (mmal_port_parameter_set_uint32(decoder->input[0], MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS,
                                        -1 - ctx->extra_decoder_buffers)) {
         av_log(avctx, AV_LOG_WARNING, "Could not set input buffering limit.\n");
     }

 #endif

     if ((status = mmal_port_format_commit(decoder->input[0])))
         goto fail;
 
     decoder->input[0]->buffer_num =
         FFMAX(decoder->input[0]->buffer_num_min, 20);
     decoder->input[0]->buffer_size =
         FFMAX(decoder->input[0]->buffer_size_min, 512 * 1024);
     ctx->pool_in = mmal_pool_create(decoder->input[0]->buffer_num, 0);
     if (!ctx->pool_in) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     if ((ret = ffmal_update_format(avctx)) < 0)
         goto fail;
 
     ctx->queue_decoded_frames = mmal_queue_create();
     if (!ctx->queue_decoded_frames)
         goto fail;
 
     decoder->input[0]->userdata = (void*)avctx;
     decoder->output[0]->userdata = (void*)avctx;
     decoder->control->userdata = (void*)avctx;
 
     if ((status = mmal_port_enable(decoder->control, control_port_cb)))
         goto fail;
     if ((status = mmal_port_enable(decoder->input[0], input_callback)))
         goto fail;
     if ((status = mmal_port_enable(decoder->output[0], output_callback)))
         goto fail;
 
     if ((status = mmal_component_enable(decoder)))
         goto fail;
 
     return 0;
 
 fail:
     ffmmal_close_decoder(avctx);
     return ret < 0 ? ret : AVERROR_UNKNOWN;
 }
 
 static void ffmmal_flush(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_COMPONENT_T *decoder = ctx->decoder;
     MMAL_STATUS_T status;
 
     ffmmal_stop_decoder(avctx);
 
     if ((status = mmal_port_enable(decoder->control, control_port_cb)))
         goto fail;
     if ((status = mmal_port_enable(decoder->input[0], input_callback)))
         goto fail;
     if ((status = mmal_port_enable(decoder->output[0], output_callback)))
         goto fail;
 
     return;
 
 fail:
     av_log(avctx, AV_LOG_ERROR, "MMAL flush error: %i\n", (int)status);
 }
 
 // Split packets and add them to the waiting_buffers list. We don't queue them
 // immediately, because it can happen that the decoder is temporarily blocked
 // (due to us not reading/returning enough output buffers) and won't accept
 // new input. (This wouldn't be an issue if MMAL input buffers always were
 // complete frames - then the input buffer just would have to be big enough.)

 // If is_extradata is set, send it as MMAL_BUFFER_HEADER_FLAG_CONFIG.
 static int ffmmal_add_packet(AVCodecContext *avctx, AVPacket *avpkt,
                              int is_extradata)

 {
     MMALDecodeContext *ctx = avctx->priv_data;
     AVBufferRef *buf = NULL;
     int size = 0;
     uint8_t *data = (uint8_t *)"";
     uint8_t *start;
     int ret = 0;
 
     if (avpkt->size) {

         if (avpkt->buf) {
             buf = av_buffer_ref(avpkt->buf);

             size = avpkt->size;
             data = avpkt->data;

         } else {

             buf = av_buffer_alloc(avpkt->size);

             if (buf) {

                 memcpy(buf->data, avpkt->data, avpkt->size);

                 size = buf->size;
                 data = buf->data;
             }

         }
         if (!buf) {
             ret = AVERROR(ENOMEM);
             goto done;
         }

         if (!is_extradata)
             ctx->packets_sent++;

     } else {

         if (ctx->eos_sent)
             goto done;

         if (!ctx->packets_sent) {
             // Short-cut the flush logic to avoid upsetting MMAL.
             ctx->eos_sent = 1;
             ctx->eos_received = 1;
             goto done;
         }

     }
 
     start = data;
 
     do {
         FFBufferEntry *buffer = av_mallocz(sizeof(*buffer));
         if (!buffer) {
             ret = AVERROR(ENOMEM);
             goto done;
         }
 
         buffer->data = data;
         buffer->length = FFMIN(size, ctx->decoder->input[0]->buffer_size);
 

         if (is_extradata)
             buffer->flags |= MMAL_BUFFER_HEADER_FLAG_CONFIG;
 

         if (data == start)
             buffer->flags |= MMAL_BUFFER_HEADER_FLAG_FRAME_START;
 
         data += buffer->length;
         size -= buffer->length;
 
         buffer->pts = avpkt->pts == AV_NOPTS_VALUE ? MMAL_TIME_UNKNOWN : avpkt->pts;
         buffer->dts = avpkt->dts == AV_NOPTS_VALUE ? MMAL_TIME_UNKNOWN : avpkt->dts;
 

         if (!size) {

             buffer->flags |= MMAL_BUFFER_HEADER_FLAG_FRAME_END;

             atomic_fetch_add(&ctx->packets_buffered, 1);

         }

 
         if (!buffer->length) {
             buffer->flags |= MMAL_BUFFER_HEADER_FLAG_EOS;
             ctx->eos_sent = 1;
         }
 
         if (buf) {
             buffer->ref = av_buffer_ref(buf);
             if (!buffer->ref) {
                 av_free(buffer);
                 ret = AVERROR(ENOMEM);
                 goto done;
             }
         }
 
         // Insert at end of the list
         if (!ctx->waiting_buffers)
             ctx->waiting_buffers = buffer;
         if (ctx->waiting_buffers_tail)
             ctx->waiting_buffers_tail->next = buffer;
         ctx->waiting_buffers_tail = buffer;
     } while (size);
 
 done:
     av_buffer_unref(&buf);
     return ret;
 }
 
 // Move prepared/split packets from waiting_buffers to the MMAL decoder.
 static int ffmmal_fill_input_port(AVCodecContext *avctx)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
 
     while (ctx->waiting_buffers) {
         MMAL_BUFFER_HEADER_T *mbuffer;
         FFBufferEntry *buffer;
         MMAL_STATUS_T status;
 
         mbuffer = mmal_queue_get(ctx->pool_in->queue);
         if (!mbuffer)
             return 0;
 
         buffer = ctx->waiting_buffers;
 
         mmal_buffer_header_reset(mbuffer);
         mbuffer->cmd = 0;
         mbuffer->pts = buffer->pts;
         mbuffer->dts = buffer->dts;
         mbuffer->flags = buffer->flags;
         mbuffer->data = buffer->data;
         mbuffer->length = buffer->length;

         mbuffer->user_data = buffer;

         mbuffer->alloc_size = ctx->decoder->input[0]->buffer_size;
 
         // Remove from start of the list
         ctx->waiting_buffers = buffer->next;
         if (ctx->waiting_buffers_tail == buffer)
             ctx->waiting_buffers_tail = NULL;

 
         if ((status = mmal_port_send_buffer(ctx->decoder->input[0], mbuffer))) {
             mmal_buffer_header_release(mbuffer);
             av_buffer_unref(&buffer->ref);

             if (buffer->flags & MMAL_BUFFER_HEADER_FLAG_FRAME_END)

                 atomic_fetch_add(&ctx->packets_buffered, -1);

             av_free(buffer);
         }

 
         if (status) {
             av_log(avctx, AV_LOG_ERROR, "MMAL error %d when sending input\n", (int)status);
             return AVERROR_UNKNOWN;
         }
     }
 
     return 0;
 }
 
 static int ffmal_copy_frame(AVCodecContext *avctx,  AVFrame *frame,
                             MMAL_BUFFER_HEADER_T *buffer)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     int ret = 0;
 

     frame->interlaced_frame = ctx->interlaced_frame;
     frame->top_field_first = ctx->top_field_first;
 

     if (avctx->pix_fmt == AV_PIX_FMT_MMAL) {
         if (!ctx->pool_out)
             return AVERROR_UNKNOWN; // format change code failed with OOM previously
 
         if ((ret = ff_decode_frame_props(avctx, frame)) < 0)
             goto done;
 
         if ((ret = ffmmal_set_ref(frame, ctx->pool_out, buffer)) < 0)
             goto done;
     } else {
         int w = FFALIGN(avctx->width, 32);
         int h = FFALIGN(avctx->height, 16);

         uint8_t *src[4];
         int linesize[4];

 
         if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
             goto done;
 

         av_image_fill_arrays(src, linesize,
                              buffer->data + buffer->type->video.offset[0],
                              avctx->pix_fmt, w, h, 1);
         av_image_copy(frame->data, frame->linesize, src, linesize,
                       avctx->pix_fmt, avctx->width, avctx->height);

     }
 

     frame->pts = buffer->pts == MMAL_TIME_UNKNOWN ? AV_NOPTS_VALUE : buffer->pts;
 #if FF_API_PKT_PTS
 FF_DISABLE_DEPRECATION_WARNINGS
     frame->pkt_pts = frame->pts;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif

     frame->pkt_dts = AV_NOPTS_VALUE;

 
 done:
     return ret;
 }
 
 // Fetch a decoded buffer and place it into the frame parameter.
 static int ffmmal_read_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame)
 {
     MMALDecodeContext *ctx = avctx->priv_data;
     MMAL_BUFFER_HEADER_T *buffer = NULL;
     MMAL_STATUS_T status = 0;
     int ret = 0;
 
     if (ctx->eos_received)
         goto done;
 
     while (1) {
         // To ensure decoding in lockstep with a constant delay between fed packets
         // and output frames, we always wait until an output buffer is available.
         // Except during start we don't know after how many input packets the decoder
         // is going to return the first buffer, and we can't distinguish decoder
         // being busy from decoder waiting for input. So just poll at the start and
         // keep feeding new data to the buffer.
         // We are pretty sure the decoder will produce output if we sent more input

         // frames than what a H.264 decoder could logically delay. This avoids too

         // excessive buffering.
         // We also wait if we sent eos, but didn't receive it yet (think of decoding
         // stream with a very low number of frames).

         if (atomic_load(&ctx->packets_buffered) > MAX_DELAYED_FRAMES ||

             (ctx->packets_sent && ctx->eos_sent)) {

             // MMAL will ignore broken input packets, which means the frame we
             // expect here may never arrive. Dealing with this correctly is
             // complicated, so here's a hack to avoid that it freezes forever
             // in this unlikely situation.
             buffer = mmal_queue_timedwait(ctx->queue_decoded_frames, 100);
             if (!buffer) {
                 av_log(avctx, AV_LOG_ERROR, "Did not get output frame from MMAL.\n");
                 ret = AVERROR_UNKNOWN;
                 goto done;
             }

         } else {
             buffer = mmal_queue_get(ctx->queue_decoded_frames);

             if (!buffer)
                 goto done;

         }
 
         ctx->eos_received |= !!(buffer->flags & MMAL_BUFFER_HEADER_FLAG_EOS);
         if (ctx->eos_received)
             goto done;
 
         if (buffer->cmd == MMAL_EVENT_FORMAT_CHANGED) {
             MMAL_COMPONENT_T *decoder = ctx->decoder;
             MMAL_EVENT_FORMAT_CHANGED_T *ev = mmal_event_format_changed_get(buffer);
             MMAL_BUFFER_HEADER_T *stale_buffer;
 
             av_log(avctx, AV_LOG_INFO, "Changing output format.\n");
 
             if ((status = mmal_port_disable(decoder->output[0])))
                 goto done;
 
             while ((stale_buffer = mmal_queue_get(ctx->queue_decoded_frames)))
                 mmal_buffer_header_release(stale_buffer);
 
             mmal_format_copy(decoder->output[0]->format, ev->format);
 
             if ((ret = ffmal_update_format(avctx)) < 0)
                 goto done;
 
             if ((status = mmal_port_enable(decoder->output[0], output_callback)))
                 goto done;
 
             if ((ret = ffmmal_fill_output_port(avctx)) < 0)
                 goto done;
 
             if ((ret = ffmmal_fill_input_port(avctx)) < 0)
                 goto done;
 
             mmal_buffer_header_release(buffer);
             continue;
         } else if (buffer->cmd) {

             av_log(avctx, AV_LOG_WARNING, "Unknown MMAL event %s on output port\n",
                    av_fourcc2str(buffer->cmd));

             goto done;
         } else if (buffer->length == 0) {
             // Unused output buffer that got drained after format change.
             mmal_buffer_header_release(buffer);
             continue;
         }
 
         ctx->frames_output++;
 
         if ((ret = ffmal_copy_frame(avctx, frame, buffer)) < 0)
             goto done;
 
         *got_frame = 1;
         break;
     }
 
 done:
     if (buffer)
         mmal_buffer_header_release(buffer);
     if (status && ret >= 0)
         ret = AVERROR_UNKNOWN;
     return ret;
 }
 
 static int ffmmal_decode(AVCodecContext *avctx, void *data, int *got_frame,
                          AVPacket *avpkt)
 {

     MMALDecodeContext *ctx = avctx->priv_data;

     AVFrame *frame = data;
     int ret = 0;
 

     if (avctx->extradata_size && !ctx->extradata_sent) {
         AVPacket pkt = {0};
         av_init_packet(&pkt);
         pkt.data = avctx->extradata;
         pkt.size = avctx->extradata_size;
         ctx->extradata_sent = 1;
         if ((ret = ffmmal_add_packet(avctx, &pkt, 1)) < 0)
             return ret;
     }
 
     if ((ret = ffmmal_add_packet(avctx, avpkt, 0)) < 0)

         return ret;
 
     if ((ret = ffmmal_fill_input_port(avctx)) < 0)
         return ret;
 
     if ((ret = ffmmal_fill_output_port(avctx)) < 0)
         return ret;
 
     if ((ret = ffmmal_read_frame(avctx, frame, got_frame)) < 0)
         return ret;
 
     // ffmmal_read_frame() can block for a while. Since the decoder is
     // asynchronous, it's a good idea to fill the ports again.
 
     if ((ret = ffmmal_fill_output_port(avctx)) < 0)
         return ret;
 
     if ((ret = ffmmal_fill_input_port(avctx)) < 0)
         return ret;
 
     return ret;
 }
 

 static const AVCodecHWConfigInternal *mmal_hw_configs[] = {
     HW_CONFIG_INTERNAL(MMAL),
     NULL
 };
 

 static const AVOption options[]={
     {"extra_buffers", "extra buffers", offsetof(MMALDecodeContext, extra_buffers), AV_OPT_TYPE_INT, {.i64 = 10}, 0, 256, 0},

     {"extra_decoder_buffers", "extra MMAL internal buffered frames", offsetof(MMALDecodeContext, extra_decoder_buffers), AV_OPT_TYPE_INT, {.i64 = 10}, 0, 256, 0},

     {NULL}
 };
 

 #define FFMMAL_DEC_CLASS(NAME) \
     static const AVClass ffmmal_##NAME##_dec_class = { \
         .class_name = "mmal_" #NAME "_dec", \

         .item_name  = av_default_item_name, \

         .option     = options, \
         .version    = LIBAVUTIL_VERSION_INT, \
     };
 
 #define FFMMAL_DEC(NAME, ID) \
     FFMMAL_DEC_CLASS(NAME) \
     AVCodec ff_##NAME##_mmal_decoder = { \
         .name           = #NAME "_mmal", \
         .long_name      = NULL_IF_CONFIG_SMALL(#NAME " (mmal)"), \
         .type           = AVMEDIA_TYPE_VIDEO, \
         .id             = ID, \
         .priv_data_size = sizeof(MMALDecodeContext), \
         .init           = ffmmal_init_decoder, \
         .close          = ffmmal_close_decoder, \
         .decode         = ffmmal_decode, \
         .flush          = ffmmal_flush, \
         .priv_class     = &ffmmal_##NAME##_dec_class, \

         .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_HARDWARE, \

         .caps_internal  = FF_CODEC_CAP_SETS_PKT_DTS, \
         .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_MMAL, \
                                                          AV_PIX_FMT_YUV420P, \
                                                          AV_PIX_FMT_NONE}, \

         .hw_configs     = mmal_hw_configs, \

         .wrapper_name   = "mmal", \

     };
 
 FFMMAL_DEC(h264, AV_CODEC_ID_H264)
 FFMMAL_DEC(mpeg2, AV_CODEC_ID_MPEG2VIDEO)

 FFMMAL_DEC(mpeg4, AV_CODEC_ID_MPEG4)

 FFMMAL_DEC(vc1, AV_CODEC_ID_VC1)