/*

 * bitpacked encoder

 *

 * Copyright (c) 2021 Limin Wang

 *

 * 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 "avcodec.h"

#include "codec_internal.h"

#include "encode.h"

#include "internal.h"

#include "put_bits.h"

#include "libavutil/pixdesc.h"

struct BitpackedContext {

    int (*encode)(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *frame);

};

static int encode_yuv422p10(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *frame)

{

    const int buf_size = avctx->height * avctx->width * avctx->bits_per_coded_sample / 8;

    int ret;

    uint8_t *dst;

    const uint16_t *y;

    const uint16_t *u;

    const uint16_t *v;

    PutBitContext pb;

    ret = ff_get_encode_buffer(avctx, pkt,  buf_size, 0);

    if (ret < 0) {

        av_log(avctx, AV_LOG_ERROR, "Error getting output packet.\n");

        return ret;

    }

    dst = pkt->data;

    init_put_bits(&pb, dst, buf_size);

    for (int i = 0; i < avctx->height; i++) {

        y = (uint16_t*)(frame->data[0] + i * frame->linesize[0]);

        u = (uint16_t*)(frame->data[1] + i * frame->linesize[1]);

        v = (uint16_t*)(frame->data[2] + i * frame->linesize[2]);

        for (int j = 0; j < avctx->width; j += 2) {

            /* u, y0, v, y1 */

            put_bits(&pb, 10, av_clip_uintp2(*u++, 10));

            put_bits(&pb, 10, av_clip_uintp2(*y++, 10));

            put_bits(&pb, 10, av_clip_uintp2(*v++, 10));

            put_bits(&pb, 10, av_clip_uintp2(*y++, 10));

        }

    }

    flush_put_bits(&pb);

    return 0;

}

static av_cold int encode_init(AVCodecContext *avctx)

{

    struct BitpackedContext *s = avctx->priv_data;

    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);

    if (avctx->width & 1) {

        av_log(avctx, AV_LOG_ERROR, "bitpacked needs even width\n");

        return AVERROR(EINVAL);

    }

    avctx->bits_per_coded_sample = av_get_bits_per_pixel(desc);

    avctx->bit_rate = ff_guess_coded_bitrate(avctx);

    if (avctx->pix_fmt == AV_PIX_FMT_YUV422P10)

        s->encode = encode_yuv422p10;

    else

        return AVERROR(EINVAL);

    return 0;

}

static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,

                        const AVFrame *frame, int *got_packet)

{

    struct BitpackedContext *s = avctx->priv_data;

    int ret;

    ret = s->encode(avctx, pkt, frame);

    if (ret)

        return ret;

    *got_packet = 1;

    return 0;

}

const FFCodec ff_bitpacked_encoder = {

    .p.name         = "bitpacked",

    CODEC_LONG_NAME("Bitpacked"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_BITPACKED,

    .priv_data_size = sizeof(struct BitpackedContext),

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |

                      AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,

    .init           = encode_init,

    FF_CODEC_ENCODE_CB(encode_frame),

    CODEC_PIXFMTS(AV_PIX_FMT_YUV422P10),

};