/*
  * Videotoolbox hardware acceleration
  *
  * copyright (c) 2012 Sebastien Zwickert
  *
  * 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
  */
 
 #include "config.h"
 #if CONFIG_VIDEOTOOLBOX
 #  include "videotoolbox.h"
 #else
 #  include "vda.h"
 #endif
 #include "vda_vt_internal.h"
 #include "libavutil/avutil.h"
 #include "bytestream.h"

 #include "h264dec.h"

 #include "mpegvideo.h"

 #include <TargetConditionals.h>

 #ifndef kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder
 #  define kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder CFSTR("RequireHardwareAcceleratedVideoDecoder")

 #endif
 
 #define VIDEOTOOLBOX_ESDS_EXTRADATA_PADDING  12
 
 static void videotoolbox_buffer_release(void *opaque, uint8_t *data)
 {
     CVPixelBufferRef cv_buffer = (CVImageBufferRef)data;
     CVPixelBufferRelease(cv_buffer);
 }
 
 static int videotoolbox_buffer_copy(VTContext *vtctx,
                                     const uint8_t *buffer,
                                     uint32_t size)
 {
     void *tmp;
 
     tmp = av_fast_realloc(vtctx->bitstream,
                          &vtctx->allocated_size,
                          size);
 
     if (!tmp)
         return AVERROR(ENOMEM);
 
     vtctx->bitstream = tmp;
     memcpy(vtctx->bitstream, buffer, size);
     vtctx->bitstream_size = size;
 
     return 0;
 }
 
 int ff_videotoolbox_alloc_frame(AVCodecContext *avctx, AVFrame *frame)
 {
     frame->width  = avctx->width;
     frame->height = avctx->height;
     frame->format = avctx->pix_fmt;
     frame->buf[0] = av_buffer_alloc(1);
 
     if (!frame->buf[0])
         return AVERROR(ENOMEM);
 
     return 0;
 }
 

 #define AV_W8(p, v) *(p) = (v)
 

 CFDataRef ff_videotoolbox_avcc_extradata_create(AVCodecContext *avctx)
 {

     H264Context *h     = avctx->priv_data;

     CFDataRef data = NULL;

     uint8_t *p;

     int vt_extradata_size = 6 + 2 + h->ps.sps->data_size + 3 + h->ps.pps->data_size;

     uint8_t *vt_extradata = av_malloc(vt_extradata_size);
     if (!vt_extradata)
         return NULL;
 
     p = vt_extradata;
 
     AV_W8(p + 0, 1); /* version */

     AV_W8(p + 1, h->ps.sps->data[1]); /* profile */
     AV_W8(p + 2, h->ps.sps->data[2]); /* profile compat */
     AV_W8(p + 3, h->ps.sps->data[3]); /* level */

     AV_W8(p + 4, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 3 (11) */
     AV_W8(p + 5, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */

     AV_WB16(p + 6, h->ps.sps->data_size);
     memcpy(p + 8, h->ps.sps->data, h->ps.sps->data_size);
     p += 8 + h->ps.sps->data_size;

     AV_W8(p + 0, 1); /* number of pps */

     AV_WB16(p + 1, h->ps.pps->data_size);
     memcpy(p + 3, h->ps.pps->data, h->ps.pps->data_size);

     p += 3 + h->ps.pps->data_size;

     av_assert0(p - vt_extradata == vt_extradata_size);
 
     data = CFDataCreate(kCFAllocatorDefault, vt_extradata, vt_extradata_size);
     av_free(vt_extradata);

     return data;
 }
 
 int ff_videotoolbox_buffer_create(VTContext *vtctx, AVFrame *frame)
 {
     av_buffer_unref(&frame->buf[0]);
 
     frame->buf[0] = av_buffer_create((uint8_t*)vtctx->frame,
                                      sizeof(vtctx->frame),
                                      videotoolbox_buffer_release,
                                      NULL,
                                      AV_BUFFER_FLAG_READONLY);
     if (!frame->buf[0]) {
         return AVERROR(ENOMEM);
     }
 
     frame->data[3] = (uint8_t*)vtctx->frame;
     vtctx->frame = NULL;
 
     return 0;
 }
 
 int ff_videotoolbox_h264_start_frame(AVCodecContext *avctx,
                                      const uint8_t *buffer,
                                      uint32_t size)
 {
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
     H264Context *h  = avctx->priv_data;
 
     vtctx->bitstream_size = 0;
 
     if (h->is_avc == 1) {
         return videotoolbox_buffer_copy(vtctx, buffer, size);
     }
 
     return 0;
 }
 
 int ff_videotoolbox_h264_decode_slice(AVCodecContext *avctx,
                                       const uint8_t *buffer,
                                       uint32_t size)
 {
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
     H264Context *h  = avctx->priv_data;
     void *tmp;
 
     if (h->is_avc == 1)
         return 0;
 
     tmp = av_fast_realloc(vtctx->bitstream,
                           &vtctx->allocated_size,
                           vtctx->bitstream_size+size+4);
     if (!tmp)
         return AVERROR(ENOMEM);
 
     vtctx->bitstream = tmp;
 
     AV_WB32(vtctx->bitstream + vtctx->bitstream_size, size);
     memcpy(vtctx->bitstream + vtctx->bitstream_size + 4, buffer, size);
 
     vtctx->bitstream_size += size + 4;
 
     return 0;
 }
 
 int ff_videotoolbox_uninit(AVCodecContext *avctx)
 {
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
     if (vtctx) {
         av_freep(&vtctx->bitstream);
         if (vtctx->frame)
             CVPixelBufferRelease(vtctx->frame);
     }
 
     return 0;
 }
 
 #if CONFIG_VIDEOTOOLBOX
 static void videotoolbox_write_mp4_descr_length(PutByteContext *pb, int length)
 {
     int i;
     uint8_t b;
 
     for (i = 3; i >= 0; i--) {
         b = (length >> (i * 7)) & 0x7F;
         if (i != 0)
             b |= 0x80;
 
         bytestream2_put_byteu(pb, b);
     }
 }
 
 static CFDataRef videotoolbox_esds_extradata_create(AVCodecContext *avctx)
 {
     CFDataRef data;
     uint8_t *rw_extradata;
     PutByteContext pb;
     int full_size = 3 + 5 + 13 + 5 + avctx->extradata_size + 3;
     // ES_DescrTag data + DecoderConfigDescrTag + data + DecSpecificInfoTag + size + SLConfigDescriptor
     int config_size = 13 + 5 + avctx->extradata_size;
     int s;
 
     if (!(rw_extradata = av_mallocz(full_size + VIDEOTOOLBOX_ESDS_EXTRADATA_PADDING)))
         return NULL;
 
     bytestream2_init_writer(&pb, rw_extradata, full_size + VIDEOTOOLBOX_ESDS_EXTRADATA_PADDING);
     bytestream2_put_byteu(&pb, 0);        // version
     bytestream2_put_ne24(&pb, 0);         // flags
 
     // elementary stream descriptor
     bytestream2_put_byteu(&pb, 0x03);     // ES_DescrTag
     videotoolbox_write_mp4_descr_length(&pb, full_size);
     bytestream2_put_ne16(&pb, 0);         // esid
     bytestream2_put_byteu(&pb, 0);        // stream priority (0-32)
 
     // decoder configuration descriptor
     bytestream2_put_byteu(&pb, 0x04);     // DecoderConfigDescrTag
     videotoolbox_write_mp4_descr_length(&pb, config_size);

     bytestream2_put_byteu(&pb, 32);       // object type indication. 32 = AV_CODEC_ID_MPEG4

     bytestream2_put_byteu(&pb, 0x11);     // stream type
     bytestream2_put_ne24(&pb, 0);         // buffer size
     bytestream2_put_ne32(&pb, 0);         // max bitrate
     bytestream2_put_ne32(&pb, 0);         // avg bitrate
 
     // decoder specific descriptor
     bytestream2_put_byteu(&pb, 0x05);     ///< DecSpecificInfoTag
     videotoolbox_write_mp4_descr_length(&pb, avctx->extradata_size);
 
     bytestream2_put_buffer(&pb, avctx->extradata, avctx->extradata_size);
 
     // SLConfigDescriptor
     bytestream2_put_byteu(&pb, 0x06);     // SLConfigDescrTag
     bytestream2_put_byteu(&pb, 0x01);     // length
     bytestream2_put_byteu(&pb, 0x02);     //
 
     s = bytestream2_size_p(&pb);
 
     data = CFDataCreate(kCFAllocatorDefault, rw_extradata, s);
 
     av_freep(&rw_extradata);
     return data;
 }
 
 static CMSampleBufferRef videotoolbox_sample_buffer_create(CMFormatDescriptionRef fmt_desc,
                                                            void *buffer,
                                                            int size)
 {
     OSStatus status;
     CMBlockBufferRef  block_buf;
     CMSampleBufferRef sample_buf;
 
     block_buf  = NULL;
     sample_buf = NULL;
 
     status = CMBlockBufferCreateWithMemoryBlock(kCFAllocatorDefault,// structureAllocator
                                                 buffer,             // memoryBlock
                                                 size,               // blockLength
                                                 kCFAllocatorNull,   // blockAllocator
                                                 NULL,               // customBlockSource
                                                 0,                  // offsetToData
                                                 size,               // dataLength
                                                 0,                  // flags
                                                 &block_buf);
 
     if (!status) {
         status = CMSampleBufferCreate(kCFAllocatorDefault,  // allocator
                                       block_buf,            // dataBuffer
                                       TRUE,                 // dataReady
                                       0,                    // makeDataReadyCallback
                                       0,                    // makeDataReadyRefcon
                                       fmt_desc,             // formatDescription
                                       1,                    // numSamples
                                       0,                    // numSampleTimingEntries
                                       NULL,                 // sampleTimingArray
                                       0,                    // numSampleSizeEntries
                                       NULL,                 // sampleSizeArray
                                       &sample_buf);
     }
 
     if (block_buf)
         CFRelease(block_buf);
 
     return sample_buf;
 }
 
 static void videotoolbox_decoder_callback(void *opaque,
                                           void *sourceFrameRefCon,
                                           OSStatus status,
                                           VTDecodeInfoFlags flags,
                                           CVImageBufferRef image_buffer,
                                           CMTime pts,
                                           CMTime duration)
 {
     AVCodecContext *avctx = opaque;
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
 
     if (vtctx->frame) {
         CVPixelBufferRelease(vtctx->frame);
         vtctx->frame = NULL;
     }
 
     if (!image_buffer) {
         av_log(NULL, AV_LOG_DEBUG, "vt decoder cb: output image buffer is null\n");
         return;
     }
 
     vtctx->frame = CVPixelBufferRetain(image_buffer);
 }
 
 static OSStatus videotoolbox_session_decode_frame(AVCodecContext *avctx)
 {
     OSStatus status;
     CMSampleBufferRef sample_buf;
     AVVideotoolboxContext *videotoolbox = avctx->hwaccel_context;
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
 
     sample_buf = videotoolbox_sample_buffer_create(videotoolbox->cm_fmt_desc,
                                                    vtctx->bitstream,
                                                    vtctx->bitstream_size);
 
     if (!sample_buf)
         return -1;
 
     status = VTDecompressionSessionDecodeFrame(videotoolbox->session,
                                                sample_buf,
                                                0,       // decodeFlags
                                                NULL,    // sourceFrameRefCon
                                                0);      // infoFlagsOut
     if (status == noErr)
         status = VTDecompressionSessionWaitForAsynchronousFrames(videotoolbox->session);
 
     CFRelease(sample_buf);
 
     return status;
 }
 
 static int videotoolbox_common_end_frame(AVCodecContext *avctx, AVFrame *frame)
 {
     int status;
     AVVideotoolboxContext *videotoolbox = avctx->hwaccel_context;
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
 
     if (!videotoolbox->session || !vtctx->bitstream)
         return AVERROR_INVALIDDATA;
 
     status = videotoolbox_session_decode_frame(avctx);
 
     if (status) {
         av_log(avctx, AV_LOG_ERROR, "Failed to decode frame (%d)\n", status);
         return AVERROR_UNKNOWN;
     }
 
     if (!vtctx->frame)
         return AVERROR_UNKNOWN;
 
     return ff_videotoolbox_buffer_create(vtctx, frame);
 }
 
 static int videotoolbox_h264_end_frame(AVCodecContext *avctx)
 {
     H264Context *h = avctx->priv_data;
     AVFrame *frame = h->cur_pic_ptr->f;
 
     return videotoolbox_common_end_frame(avctx, frame);
 }
 
 static int videotoolbox_mpeg_start_frame(AVCodecContext *avctx,
                                          const uint8_t *buffer,
                                          uint32_t size)
 {
     VTContext *vtctx = avctx->internal->hwaccel_priv_data;
 
     return videotoolbox_buffer_copy(vtctx, buffer, size);
 }
 
 static int videotoolbox_mpeg_decode_slice(AVCodecContext *avctx,
                                           const uint8_t *buffer,
                                           uint32_t size)
 {
     return 0;
 }
 
 static int videotoolbox_mpeg_end_frame(AVCodecContext *avctx)
 {
     MpegEncContext *s = avctx->priv_data;
     AVFrame *frame = s->current_picture_ptr->f;
 
     return videotoolbox_common_end_frame(avctx, frame);
 }
 
 static CFDictionaryRef videotoolbox_decoder_config_create(CMVideoCodecType codec_type,
                                                           AVCodecContext *avctx)
 {
     CFMutableDictionaryRef config_info = CFDictionaryCreateMutable(kCFAllocatorDefault,

                                                                    0,

                                                                    &kCFTypeDictionaryKeyCallBacks,
                                                                    &kCFTypeDictionaryValueCallBacks);
 
     CFDictionarySetValue(config_info,

                          kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder,

                          kCFBooleanTrue);
 
     if (avctx->extradata_size) {
         CFMutableDictionaryRef avc_info;
         CFDataRef data = NULL;
 
         avc_info = CFDictionaryCreateMutable(kCFAllocatorDefault,
                                              1,
                                              &kCFTypeDictionaryKeyCallBacks,
                                              &kCFTypeDictionaryValueCallBacks);
 
         switch (codec_type) {
         case kCMVideoCodecType_MPEG4Video :
             data = videotoolbox_esds_extradata_create(avctx);
             if (data)
                 CFDictionarySetValue(avc_info, CFSTR("esds"), data);
             break;
         case kCMVideoCodecType_H264 :
             data = ff_videotoolbox_avcc_extradata_create(avctx);
             if (data)
                 CFDictionarySetValue(avc_info, CFSTR("avcC"), data);
             break;
         default:
             break;
         }
 
         CFDictionarySetValue(config_info,
                 kCMFormatDescriptionExtension_SampleDescriptionExtensionAtoms,
                 avc_info);
 
         if (data)
             CFRelease(data);
 
         CFRelease(avc_info);
     }
     return config_info;
 }
 
 static CFDictionaryRef videotoolbox_buffer_attributes_create(int width,
                                                              int height,
                                                              OSType pix_fmt)
 {
     CFMutableDictionaryRef buffer_attributes;
     CFMutableDictionaryRef io_surface_properties;
     CFNumberRef cv_pix_fmt;
     CFNumberRef w;
     CFNumberRef h;
 
     w = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &width);
     h = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &height);
     cv_pix_fmt = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &pix_fmt);
 
     buffer_attributes = CFDictionaryCreateMutable(kCFAllocatorDefault,
                                                   4,
                                                   &kCFTypeDictionaryKeyCallBacks,
                                                   &kCFTypeDictionaryValueCallBacks);
     io_surface_properties = CFDictionaryCreateMutable(kCFAllocatorDefault,
                                                       0,
                                                       &kCFTypeDictionaryKeyCallBacks,
                                                       &kCFTypeDictionaryValueCallBacks);
 

     if (pix_fmt)
         CFDictionarySetValue(buffer_attributes, kCVPixelBufferPixelFormatTypeKey, cv_pix_fmt);

     CFDictionarySetValue(buffer_attributes, kCVPixelBufferIOSurfacePropertiesKey, io_surface_properties);
     CFDictionarySetValue(buffer_attributes, kCVPixelBufferWidthKey, w);
     CFDictionarySetValue(buffer_attributes, kCVPixelBufferHeightKey, h);

 #if TARGET_OS_IPHONE
     CFDictionarySetValue(buffer_attributes, kCVPixelBufferOpenGLESCompatibilityKey, kCFBooleanTrue);
 #else

     CFDictionarySetValue(buffer_attributes, kCVPixelBufferIOSurfaceOpenGLTextureCompatibilityKey, kCFBooleanTrue);

 #endif

 
     CFRelease(io_surface_properties);
     CFRelease(cv_pix_fmt);
     CFRelease(w);
     CFRelease(h);
 
     return buffer_attributes;
 }
 

 static CMVideoFormatDescriptionRef videotoolbox_format_desc_create(CMVideoCodecType codec_type,

                                                                    CFDictionaryRef decoder_spec,
                                                                    int width,
                                                                    int height)
 {

     CMFormatDescriptionRef cm_fmt_desc;
     OSStatus status;

     status = CMVideoFormatDescriptionCreate(kCFAllocatorDefault,
                                             codec_type,
                                             width,
                                             height,
                                             decoder_spec, // Dictionary of extension
                                             &cm_fmt_desc);

     if (status)
         return NULL;

 
     return cm_fmt_desc;
 }
 
 static int videotoolbox_default_init(AVCodecContext *avctx)
 {
     AVVideotoolboxContext *videotoolbox = avctx->hwaccel_context;
     OSStatus status;
     VTDecompressionOutputCallbackRecord decoder_cb;
     CFDictionaryRef decoder_spec;
     CFDictionaryRef buf_attr;
 
     if (!videotoolbox) {
         av_log(avctx, AV_LOG_ERROR, "hwaccel context is not set\n");
         return -1;
     }
 
     switch( avctx->codec_id ) {
     case AV_CODEC_ID_H263 :
         videotoolbox->cm_codec_type = kCMVideoCodecType_H263;
         break;
     case AV_CODEC_ID_H264 :
         videotoolbox->cm_codec_type = kCMVideoCodecType_H264;
         break;
     case AV_CODEC_ID_MPEG1VIDEO :
         videotoolbox->cm_codec_type = kCMVideoCodecType_MPEG1Video;
         break;
     case AV_CODEC_ID_MPEG2VIDEO :
         videotoolbox->cm_codec_type = kCMVideoCodecType_MPEG2Video;
         break;
     case AV_CODEC_ID_MPEG4 :
         videotoolbox->cm_codec_type = kCMVideoCodecType_MPEG4Video;
         break;
     default :
         break;
     }
 
     decoder_spec = videotoolbox_decoder_config_create(videotoolbox->cm_codec_type, avctx);
 

     videotoolbox->cm_fmt_desc = videotoolbox_format_desc_create(videotoolbox->cm_codec_type,

                                                                 decoder_spec,
                                                                 avctx->width,
                                                                 avctx->height);
     if (!videotoolbox->cm_fmt_desc) {
         if (decoder_spec)
             CFRelease(decoder_spec);
 
         av_log(avctx, AV_LOG_ERROR, "format description creation failed\n");
         return -1;
     }
 
     buf_attr = videotoolbox_buffer_attributes_create(avctx->width,
                                                      avctx->height,
                                                      videotoolbox->cv_pix_fmt_type);
 
     decoder_cb.decompressionOutputCallback = videotoolbox_decoder_callback;
     decoder_cb.decompressionOutputRefCon   = avctx;
 
     status = VTDecompressionSessionCreate(NULL,                      // allocator
                                           videotoolbox->cm_fmt_desc, // videoFormatDescription
                                           decoder_spec,              // videoDecoderSpecification
                                           buf_attr,                  // destinationImageBufferAttributes
                                           &decoder_cb,               // outputCallback
                                           &videotoolbox->session);   // decompressionSessionOut
 
     if (decoder_spec)
         CFRelease(decoder_spec);
     if (buf_attr)
         CFRelease(buf_attr);
 
     switch (status) {
     case kVTVideoDecoderNotAvailableNowErr:
     case kVTVideoDecoderUnsupportedDataFormatErr:
         return AVERROR(ENOSYS);
     case kVTVideoDecoderMalfunctionErr:
         return AVERROR(EINVAL);
     case kVTVideoDecoderBadDataErr :
         return AVERROR_INVALIDDATA;
     case 0:
         return 0;
     default:
         return AVERROR_UNKNOWN;
     }
 }
 
 static void videotoolbox_default_free(AVCodecContext *avctx)
 {
     AVVideotoolboxContext *videotoolbox = avctx->hwaccel_context;
 
     if (videotoolbox) {
         if (videotoolbox->cm_fmt_desc)
             CFRelease(videotoolbox->cm_fmt_desc);
 

         if (videotoolbox->session) {

             VTDecompressionSessionInvalidate(videotoolbox->session);

             CFRelease(videotoolbox->session);
         }

     }
 }
 
 AVHWAccel ff_h263_videotoolbox_hwaccel = {
     .name           = "h263_videotoolbox",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_H263,
     .pix_fmt        = AV_PIX_FMT_VIDEOTOOLBOX,
     .alloc_frame    = ff_videotoolbox_alloc_frame,
     .start_frame    = videotoolbox_mpeg_start_frame,
     .decode_slice   = videotoolbox_mpeg_decode_slice,
     .end_frame      = videotoolbox_mpeg_end_frame,
     .uninit         = ff_videotoolbox_uninit,
     .priv_data_size = sizeof(VTContext),
 };
 
 AVHWAccel ff_h264_videotoolbox_hwaccel = {
     .name           = "h264_videotoolbox",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_H264,
     .pix_fmt        = AV_PIX_FMT_VIDEOTOOLBOX,
     .alloc_frame    = ff_videotoolbox_alloc_frame,
     .start_frame    = ff_videotoolbox_h264_start_frame,
     .decode_slice   = ff_videotoolbox_h264_decode_slice,
     .end_frame      = videotoolbox_h264_end_frame,
     .uninit         = ff_videotoolbox_uninit,
     .priv_data_size = sizeof(VTContext),
 };
 
 AVHWAccel ff_mpeg1_videotoolbox_hwaccel = {
     .name           = "mpeg1_videotoolbox",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_MPEG1VIDEO,
     .pix_fmt        = AV_PIX_FMT_VIDEOTOOLBOX,
     .alloc_frame    = ff_videotoolbox_alloc_frame,
     .start_frame    = videotoolbox_mpeg_start_frame,
     .decode_slice   = videotoolbox_mpeg_decode_slice,
     .end_frame      = videotoolbox_mpeg_end_frame,
     .uninit         = ff_videotoolbox_uninit,
     .priv_data_size = sizeof(VTContext),
 };
 
 AVHWAccel ff_mpeg2_videotoolbox_hwaccel = {
     .name           = "mpeg2_videotoolbox",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_MPEG2VIDEO,
     .pix_fmt        = AV_PIX_FMT_VIDEOTOOLBOX,
     .alloc_frame    = ff_videotoolbox_alloc_frame,
     .start_frame    = videotoolbox_mpeg_start_frame,
     .decode_slice   = videotoolbox_mpeg_decode_slice,
     .end_frame      = videotoolbox_mpeg_end_frame,
     .uninit         = ff_videotoolbox_uninit,
     .priv_data_size = sizeof(VTContext),
 };
 
 AVHWAccel ff_mpeg4_videotoolbox_hwaccel = {
     .name           = "mpeg4_videotoolbox",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_MPEG4,
     .pix_fmt        = AV_PIX_FMT_VIDEOTOOLBOX,
     .alloc_frame    = ff_videotoolbox_alloc_frame,
     .start_frame    = videotoolbox_mpeg_start_frame,
     .decode_slice   = videotoolbox_mpeg_decode_slice,
     .end_frame      = videotoolbox_mpeg_end_frame,
     .uninit         = ff_videotoolbox_uninit,
     .priv_data_size = sizeof(VTContext),
 };
 
 AVVideotoolboxContext *av_videotoolbox_alloc_context(void)
 {
     AVVideotoolboxContext *ret = av_mallocz(sizeof(*ret));
 
     if (ret) {
         ret->output_callback = videotoolbox_decoder_callback;
         ret->cv_pix_fmt_type = kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange;
     }
 
     return ret;
 }
 
 int av_videotoolbox_default_init(AVCodecContext *avctx)
 {
     return av_videotoolbox_default_init2(avctx, NULL);
 }
 
 int av_videotoolbox_default_init2(AVCodecContext *avctx, AVVideotoolboxContext *vtctx)
 {
     avctx->hwaccel_context = vtctx ?: av_videotoolbox_alloc_context();
     if (!avctx->hwaccel_context)
         return AVERROR(ENOMEM);
     return videotoolbox_default_init(avctx);
 }
 
 void av_videotoolbox_default_free(AVCodecContext *avctx)
 {
 
     videotoolbox_default_free(avctx);
     av_freep(&avctx->hwaccel_context);
 }
 #endif /* CONFIG_VIDEOTOOLBOX */