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6b77a10e43
This was predictably nightmarish, given how ridiculous mpeg4 is.
I had to stare at the cuvid parser output for a long time to work
out what each field was supposed to be, and even then, I still don't
fully understand some of them. Particularly:
vop_coded: If I'm reading the decoder correctly, this flag will always
be 1 as the decoder will not pass the hwaccel any frame
where it is not 1.
divx_flags: There's obviously no documentation on what the possible
flags are. I simply observed that this is '0' for a
normal bitstream and '5' for packed b-frames.
gmc_enabled: I had a number of guesses as to what this mapped to.
I picked the condition I did based on when the cuvid
parser was setting flag.
Also note that as with the vdpau hwaccel, the decoder needs to
consume the entire frame and not the slice.
122 lines
4.7 KiB
C
122 lines
4.7 KiB
C
/*
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* MPEG-4 Part 2 HW decode acceleration through NVDEC
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*
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* Copyright (c) 2017 Philip Langdale
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "mpeg4video.h"
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#include "nvdec.h"
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#include "decode.h"
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static int nvdec_mpeg4_start_frame(AVCodecContext *avctx, const uint8_t *buffer, uint32_t size)
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{
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Mpeg4DecContext *m = avctx->priv_data;
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MpegEncContext *s = &m->m;
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NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
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CUVIDPICPARAMS *pp = &ctx->pic_params;
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CUVIDMPEG4PICPARAMS *ppc = &pp->CodecSpecific.mpeg4;
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FrameDecodeData *fdd;
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NVDECFrame *cf;
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AVFrame *cur_frame = s->current_picture.f;
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int ret, i;
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ret = ff_nvdec_start_frame(avctx, cur_frame);
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if (ret < 0)
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return ret;
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fdd = (FrameDecodeData*)cur_frame->private_ref->data;
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cf = (NVDECFrame*)fdd->hwaccel_priv;
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*pp = (CUVIDPICPARAMS) {
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.PicWidthInMbs = (cur_frame->width + 15) / 16,
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.FrameHeightInMbs = (cur_frame->height + 15) / 16,
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.CurrPicIdx = cf->idx,
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.intra_pic_flag = s->pict_type == AV_PICTURE_TYPE_I,
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.ref_pic_flag = s->pict_type == AV_PICTURE_TYPE_I ||
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s->pict_type == AV_PICTURE_TYPE_P ||
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s->pict_type == AV_PICTURE_TYPE_S,
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.CodecSpecific.mpeg4 = {
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.ForwardRefIdx = ff_nvdec_get_ref_idx(s->last_picture.f),
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.BackwardRefIdx = ff_nvdec_get_ref_idx(s->next_picture.f),
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.video_object_layer_width = s->width,
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.video_object_layer_height = s->height,
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.vop_time_increment_bitcount = m->time_increment_bits,
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.top_field_first = s->top_field_first,
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.resync_marker_disable = !m->resync_marker,
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.quant_type = s->mpeg_quant,
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.quarter_sample = s->quarter_sample,
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.short_video_header = avctx->codec->id == AV_CODEC_ID_H263,
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.divx_flags = s->divx_packed ? 5 : 0,
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.vop_coding_type = s->pict_type - AV_PICTURE_TYPE_I,
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.vop_coded = 1,
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.vop_rounding_type = s->no_rounding,
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.alternate_vertical_scan_flag = s->alternate_scan,
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.interlaced = !s->progressive_sequence,
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.vop_fcode_forward = s->f_code,
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.vop_fcode_backward = s->b_code,
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.trd = { s->pp_time, s->pp_field_time >> 1 },
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.trb = { s->pb_time, s->pb_field_time >> 1 },
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.gmc_enabled = s->pict_type == AV_PICTURE_TYPE_S &&
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m->vol_sprite_usage == GMC_SPRITE,
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}
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};
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for (i = 0; i < 64; ++i) {
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ppc->QuantMatrixIntra[i] = s->intra_matrix[i];
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ppc->QuantMatrixInter[i] = s->inter_matrix[i];
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}
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// We need to pass the full frame buffer and not just the slice
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return ff_nvdec_simple_decode_slice(avctx, buffer, size);
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}
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static int nvdec_mpeg4_decode_slice(AVCodecContext *avctx, const uint8_t *buffer, uint32_t size)
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{
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return 0;
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}
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static int nvdec_mpeg4_frame_params(AVCodecContext *avctx,
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AVBufferRef *hw_frames_ctx)
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{
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// Each frame can at most have one P and one B reference
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return ff_nvdec_frame_params(avctx, hw_frames_ctx, 2);
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}
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AVHWAccel ff_mpeg4_nvdec_hwaccel = {
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.name = "mpeg4_nvdec",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_MPEG4,
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.pix_fmt = AV_PIX_FMT_CUDA,
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.start_frame = nvdec_mpeg4_start_frame,
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.end_frame = ff_nvdec_simple_end_frame,
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.decode_slice = nvdec_mpeg4_decode_slice,
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.frame_params = nvdec_mpeg4_frame_params,
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.init = ff_nvdec_decode_init,
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.uninit = ff_nvdec_decode_uninit,
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.priv_data_size = sizeof(NVDECContext),
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};
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