/*
 * Copyright (c) 2010, Google, Inc.
 *
 * 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
 * VP8 encoder support via libvpx
 */

#define VPX_DISABLE_CTRL_TYPECHECKS 1
#define VPX_CODEC_DISABLE_COMPAT    1
#include <vpx/vpx_encoder.h>
#include <vpx/vp8cx.h>

#include "avcodec.h"
#include "internal.h"
#include "libavutil/avassert.h"
#include "libavutil/base64.h"
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"

/**
 * Portion of struct vpx_codec_cx_pkt from vpx_encoder.h.
 * One encoded frame returned from the library.
 */
struct FrameListData {
    void *buf;                       /**< compressed data buffer */
    size_t sz;                       /**< length of compressed data */
    void *buf_alpha;
    size_t sz_alpha;
    int64_t pts;                     /**< time stamp to show frame
                                          (in timebase units) */
    unsigned long duration;          /**< duration to show frame
                                          (in timebase units) */
    uint32_t flags;                  /**< flags for this frame */
    uint64_t sse[4];
    int have_sse;                    /**< true if we have pending sse[] */
    uint64_t frame_number;
    struct FrameListData *next;
};

typedef struct VP8EncoderContext {
    AVClass *class;
    struct vpx_codec_ctx encoder;
    struct vpx_image rawimg;
    struct vpx_codec_ctx encoder_alpha;
    struct vpx_image rawimg_alpha;
    uint8_t is_alpha;
    struct vpx_fixed_buf twopass_stats;
    int deadline; //i.e., RT/GOOD/BEST
    uint64_t sse[4];
    int have_sse; /**< true if we have pending sse[] */
    uint64_t frame_number;
    struct FrameListData *coded_frame_list;

    int cpu_used;
    /**
     * VP8 specific flags, see VP8F_* below.
     */
    int flags;
#define VP8F_ERROR_RESILIENT 0x00000001 ///< Enable measures appropriate for streaming over lossy links
#define VP8F_AUTO_ALT_REF    0x00000002 ///< Enable automatic alternate reference frame generation

    int auto_alt_ref;

    int arnr_max_frames;
    int arnr_strength;
    int arnr_type;

    int lag_in_frames;
    int error_resilient;
    int crf;
    int max_intra_rate;
} VP8Context;

/** String mappings for enum vp8e_enc_control_id */
static const char *const ctlidstr[] = {
    [VP8E_UPD_ENTROPY]           = "VP8E_UPD_ENTROPY",
    [VP8E_UPD_REFERENCE]         = "VP8E_UPD_REFERENCE",
    [VP8E_USE_REFERENCE]         = "VP8E_USE_REFERENCE",
    [VP8E_SET_ROI_MAP]           = "VP8E_SET_ROI_MAP",
    [VP8E_SET_ACTIVEMAP]         = "VP8E_SET_ACTIVEMAP",
    [VP8E_SET_SCALEMODE]         = "VP8E_SET_SCALEMODE",
    [VP8E_SET_CPUUSED]           = "VP8E_SET_CPUUSED",
    [VP8E_SET_ENABLEAUTOALTREF]  = "VP8E_SET_ENABLEAUTOALTREF",
    [VP8E_SET_NOISE_SENSITIVITY] = "VP8E_SET_NOISE_SENSITIVITY",
    [VP8E_SET_SHARPNESS]         = "VP8E_SET_SHARPNESS",
    [VP8E_SET_STATIC_THRESHOLD]  = "VP8E_SET_STATIC_THRESHOLD",
    [VP8E_SET_TOKEN_PARTITIONS]  = "VP8E_SET_TOKEN_PARTITIONS",
    [VP8E_GET_LAST_QUANTIZER]    = "VP8E_GET_LAST_QUANTIZER",
    [VP8E_SET_ARNR_MAXFRAMES]    = "VP8E_SET_ARNR_MAXFRAMES",
    [VP8E_SET_ARNR_STRENGTH]     = "VP8E_SET_ARNR_STRENGTH",
    [VP8E_SET_ARNR_TYPE]         = "VP8E_SET_ARNR_TYPE",
    [VP8E_SET_CQ_LEVEL]          = "VP8E_SET_CQ_LEVEL",
    [VP8E_SET_MAX_INTRA_BITRATE_PCT] = "VP8E_SET_MAX_INTRA_BITRATE_PCT",
};

static av_cold void log_encoder_error(AVCodecContext *avctx, const char *desc)
{
    VP8Context *ctx = avctx->priv_data;
    const char *error  = vpx_codec_error(&ctx->encoder);
    const char *detail = vpx_codec_error_detail(&ctx->encoder);

    av_log(avctx, AV_LOG_ERROR, "%s: %s\n", desc, error);
    if (detail)
        av_log(avctx, AV_LOG_ERROR, "  Additional information: %s\n", detail);
}

static av_cold void dump_enc_cfg(AVCodecContext *avctx,
                                 const struct vpx_codec_enc_cfg *cfg)
{
    int width = -30;
    int level = AV_LOG_DEBUG;

    av_log(avctx, level, "vpx_codec_enc_cfg\n");
    av_log(avctx, level, "generic settings\n"
           "  %*s%u\n  %*s%u\n  %*s%u\n  %*s%u\n  %*s%u\n"
           "  %*s{%u/%u}\n  %*s%u\n  %*s%d\n  %*s%u\n",
           width, "g_usage:",           cfg->g_usage,
           width, "g_threads:",         cfg->g_threads,
           width, "g_profile:",         cfg->g_profile,
           width, "g_w:",               cfg->g_w,
           width, "g_h:",               cfg->g_h,
           width, "g_timebase:",        cfg->g_timebase.num, cfg->g_timebase.den,
           width, "g_error_resilient:", cfg->g_error_resilient,
           width, "g_pass:",            cfg->g_pass,
           width, "g_lag_in_frames:",   cfg->g_lag_in_frames);
    av_log(avctx, level, "rate control settings\n"
           "  %*s%u\n  %*s%u\n  %*s%u\n  %*s%u\n"
           "  %*s%d\n  %*s%p(%zu)\n  %*s%u\n",
           width, "rc_dropframe_thresh:",   cfg->rc_dropframe_thresh,
           width, "rc_resize_allowed:",     cfg->rc_resize_allowed,
           width, "rc_resize_up_thresh:",   cfg->rc_resize_up_thresh,
           width, "rc_resize_down_thresh:", cfg->rc_resize_down_thresh,
           width, "rc_end_usage:",          cfg->rc_end_usage,
           width, "rc_twopass_stats_in:",   cfg->rc_twopass_stats_in.buf, cfg->rc_twopass_stats_in.sz,
           width, "rc_target_bitrate:",     cfg->rc_target_bitrate);
    av_log(avctx, level, "quantizer settings\n"
           "  %*s%u\n  %*s%u\n",
           width, "rc_min_quantizer:", cfg->rc_min_quantizer,
           width, "rc_max_quantizer:", cfg->rc_max_quantizer);
    av_log(avctx, level, "bitrate tolerance\n"
           "  %*s%u\n  %*s%u\n",
           width, "rc_undershoot_pct:", cfg->rc_undershoot_pct,
           width, "rc_overshoot_pct:",  cfg->rc_overshoot_pct);
    av_log(avctx, level, "decoder buffer model\n"
            "  %*s%u\n  %*s%u\n  %*s%u\n",
            width, "rc_buf_sz:",         cfg->rc_buf_sz,
            width, "rc_buf_initial_sz:", cfg->rc_buf_initial_sz,
            width, "rc_buf_optimal_sz:", cfg->rc_buf_optimal_sz);
    av_log(avctx, level, "2 pass rate control settings\n"
           "  %*s%u\n  %*s%u\n  %*s%u\n",
           width, "rc_2pass_vbr_bias_pct:",       cfg->rc_2pass_vbr_bias_pct,
           width, "rc_2pass_vbr_minsection_pct:", cfg->rc_2pass_vbr_minsection_pct,
           width, "rc_2pass_vbr_maxsection_pct:", cfg->rc_2pass_vbr_maxsection_pct);
    av_log(avctx, level, "keyframing settings\n"
           "  %*s%d\n  %*s%u\n  %*s%u\n",
           width, "kf_mode:",     cfg->kf_mode,
           width, "kf_min_dist:", cfg->kf_min_dist,
           width, "kf_max_dist:", cfg->kf_max_dist);
    av_log(avctx, level, "\n");
}

static void coded_frame_add(void *list, struct FrameListData *cx_frame)
{
    struct FrameListData **p = list;

    while (*p != NULL)
        p = &(*p)->next;
    *p = cx_frame;
    cx_frame->next = NULL;
}

static av_cold void free_coded_frame(struct FrameListData *cx_frame)
{
    av_freep(&cx_frame->buf);
    if (cx_frame->buf_alpha)
        av_freep(&cx_frame->buf_alpha);
    av_freep(&cx_frame);
}

static av_cold void free_frame_list(struct FrameListData *list)
{
    struct FrameListData *p = list;

    while (p) {
        list = list->next;
        free_coded_frame(p);
        p = list;
    }
}

static av_cold int codecctl_int(AVCodecContext *avctx,
                                enum vp8e_enc_control_id id, int val)
{
    VP8Context *ctx = avctx->priv_data;
    char buf[80];
    int width = -30;
    int res;

    snprintf(buf, sizeof(buf), "%s:", ctlidstr[id]);
    av_log(avctx, AV_LOG_DEBUG, "  %*s%d\n", width, buf, val);

    res = vpx_codec_control(&ctx->encoder, id, val);
    if (res != VPX_CODEC_OK) {
        snprintf(buf, sizeof(buf), "Failed to set %s codec control",
                 ctlidstr[id]);
        log_encoder_error(avctx, buf);
    }

    return res == VPX_CODEC_OK ? 0 : AVERROR(EINVAL);
}

static av_cold int vp8_free(AVCodecContext *avctx)
{
    VP8Context *ctx = avctx->priv_data;

    vpx_codec_destroy(&ctx->encoder);
    if (ctx->is_alpha)
        vpx_codec_destroy(&ctx->encoder_alpha);
    av_freep(&ctx->twopass_stats.buf);
    av_freep(&avctx->coded_frame);
    av_freep(&avctx->stats_out);
    free_frame_list(ctx->coded_frame_list);
    return 0;
}

static av_cold int vpx_init(AVCodecContext *avctx,
                            const struct vpx_codec_iface *iface)
{
    VP8Context *ctx = avctx->priv_data;
    struct vpx_codec_enc_cfg enccfg;
    struct vpx_codec_enc_cfg enccfg_alpha;
    vpx_codec_flags_t flags = (avctx->flags & CODEC_FLAG_PSNR) ? VPX_CODEC_USE_PSNR : 0;
    int res;

    av_log(avctx, AV_LOG_INFO, "%s\n", vpx_codec_version_str());
    av_log(avctx, AV_LOG_VERBOSE, "%s\n", vpx_codec_build_config());

    if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P)
        ctx->is_alpha = 1;

    if ((res = vpx_codec_enc_config_default(iface, &enccfg, 0)) != VPX_CODEC_OK) {
        av_log(avctx, AV_LOG_ERROR, "Failed to get config: %s\n",
               vpx_codec_err_to_string(res));
        return AVERROR(EINVAL);
    }

    if(!avctx->bit_rate)
        if(avctx->rc_max_rate || avctx->rc_buffer_size || avctx->rc_initial_buffer_occupancy) {
            av_log( avctx, AV_LOG_ERROR, "Rate control parameters set without a bitrate\n");
            return AVERROR(EINVAL);
        }

    dump_enc_cfg(avctx, &enccfg);

    enccfg.g_w            = avctx->width;
    enccfg.g_h            = avctx->height;
    enccfg.g_timebase.num = avctx->time_base.num;
    enccfg.g_timebase.den = avctx->time_base.den;
    enccfg.g_threads      = avctx->thread_count;
    enccfg.g_lag_in_frames= ctx->lag_in_frames;

    if (avctx->flags & CODEC_FLAG_PASS1)
        enccfg.g_pass = VPX_RC_FIRST_PASS;
    else if (avctx->flags & CODEC_FLAG_PASS2)
        enccfg.g_pass = VPX_RC_LAST_PASS;
    else
        enccfg.g_pass = VPX_RC_ONE_PASS;

    if (avctx->rc_min_rate == avctx->rc_max_rate &&
        avctx->rc_min_rate == avctx->bit_rate && avctx->bit_rate)
        enccfg.rc_end_usage = VPX_CBR;
    else if (ctx->crf)
        enccfg.rc_end_usage = VPX_CQ;

    if (avctx->bit_rate) {
        enccfg.rc_target_bitrate = av_rescale_rnd(avctx->bit_rate, 1, 1000,
                                                AV_ROUND_NEAR_INF);
    } else {
        if (enccfg.rc_end_usage == VPX_CQ) {
            enccfg.rc_target_bitrate = 1000000;
        } else {
            avctx->bit_rate = enccfg.rc_target_bitrate * 1000;
            av_log(avctx, AV_LOG_WARNING,
                   "Neither bitrate nor constrained quality specified, using default bitrate of %dkbit/sec\n",
                   enccfg.rc_target_bitrate);
        }
    }

    if (avctx->qmin >= 0)
        enccfg.rc_min_quantizer = avctx->qmin;
    if (avctx->qmax > 0)
        enccfg.rc_max_quantizer = avctx->qmax;

    if (enccfg.rc_end_usage == VPX_CQ) {
        if (ctx->crf < enccfg.rc_min_quantizer || ctx->crf > enccfg.rc_max_quantizer) {
                av_log(avctx, AV_LOG_ERROR,
                       "CQ level must be between minimum and maximum quantizer value (%d-%d)\n",
                       enccfg.rc_min_quantizer, enccfg.rc_max_quantizer);
                return AVERROR(EINVAL);
        }
    }

    enccfg.rc_dropframe_thresh = avctx->frame_skip_threshold;

    //0-100 (0 => CBR, 100 => VBR)
    enccfg.rc_2pass_vbr_bias_pct           = round(avctx->qcompress * 100);
    if (avctx->bit_rate)
        enccfg.rc_2pass_vbr_minsection_pct     =
            avctx->rc_min_rate * 100LL / avctx->bit_rate;
    if (avctx->rc_max_rate)
        enccfg.rc_2pass_vbr_maxsection_pct =
            avctx->rc_max_rate * 100LL / avctx->bit_rate;

    if (avctx->rc_buffer_size)
        enccfg.rc_buf_sz         =
            avctx->rc_buffer_size * 1000LL / avctx->bit_rate;
    if (avctx->rc_initial_buffer_occupancy)
        enccfg.rc_buf_initial_sz =
            avctx->rc_initial_buffer_occupancy * 1000LL / avctx->bit_rate;
    enccfg.rc_buf_optimal_sz     = enccfg.rc_buf_sz * 5 / 6;
    enccfg.rc_undershoot_pct     = round(avctx->rc_buffer_aggressivity * 100);

    //_enc_init() will balk if kf_min_dist differs from max w/VPX_KF_AUTO
    if (avctx->keyint_min >= 0 && avctx->keyint_min == avctx->gop_size)
        enccfg.kf_min_dist = avctx->keyint_min;
    if (avctx->gop_size >= 0)
        enccfg.kf_max_dist = avctx->gop_size;

    if (enccfg.g_pass == VPX_RC_FIRST_PASS)
        enccfg.g_lag_in_frames = 0;
    else if (enccfg.g_pass == VPX_RC_LAST_PASS) {
        int decode_size;

        if (!avctx->stats_in) {
            av_log(avctx, AV_LOG_ERROR, "No stats file for second pass\n");
            return AVERROR_INVALIDDATA;
        }

        ctx->twopass_stats.sz  = strlen(avctx->stats_in) * 3 / 4;
        ctx->twopass_stats.buf = av_malloc(ctx->twopass_stats.sz);
        if (!ctx->twopass_stats.buf) {
            av_log(avctx, AV_LOG_ERROR,
                   "Stat buffer alloc (%zu bytes) failed\n",
                   ctx->twopass_stats.sz);
            return AVERROR(ENOMEM);
        }
        decode_size = av_base64_decode(ctx->twopass_stats.buf, avctx->stats_in,
                                       ctx->twopass_stats.sz);
        if (decode_size < 0) {
            av_log(avctx, AV_LOG_ERROR, "Stat buffer decode failed\n");
            return AVERROR_INVALIDDATA;
        }

        ctx->twopass_stats.sz      = decode_size;
        enccfg.rc_twopass_stats_in = ctx->twopass_stats;
    }

    /* 0-3: For non-zero values the encoder increasingly optimizes for reduced
       complexity playback on low powered devices at the expense of encode
       quality. */
   if (avctx->profile != FF_PROFILE_UNKNOWN)
       enccfg.g_profile = avctx->profile;

    enccfg.g_error_resilient = ctx->error_resilient || ctx->flags & VP8F_ERROR_RESILIENT;

    dump_enc_cfg(avctx, &enccfg);
    /* Construct Encoder Context */
    res = vpx_codec_enc_init(&ctx->encoder, iface, &enccfg, flags);
    if (res != VPX_CODEC_OK) {
        log_encoder_error(avctx, "Failed to initialize encoder");
        return AVERROR(EINVAL);
    }

    if (ctx->is_alpha) {
        enccfg_alpha = enccfg;
        res = vpx_codec_enc_init(&ctx->encoder_alpha, iface, &enccfg_alpha, flags);
        if (res != VPX_CODEC_OK) {
            log_encoder_error(avctx, "Failed to initialize alpha encoder");
            return AVERROR(EINVAL);
        }
    }

    //codec control failures are currently treated only as warnings
    av_log(avctx, AV_LOG_DEBUG, "vpx_codec_control\n");
    if (ctx->cpu_used != INT_MIN)
        codecctl_int(avctx, VP8E_SET_CPUUSED,          ctx->cpu_used);
    if (ctx->flags & VP8F_AUTO_ALT_REF)
        ctx->auto_alt_ref = 1;
    if (ctx->auto_alt_ref >= 0)
        codecctl_int(avctx, VP8E_SET_ENABLEAUTOALTREF, ctx->auto_alt_ref);
    if (ctx->arnr_max_frames >= 0)
        codecctl_int(avctx, VP8E_SET_ARNR_MAXFRAMES,   ctx->arnr_max_frames);
    if (ctx->arnr_strength >= 0)
        codecctl_int(avctx, VP8E_SET_ARNR_STRENGTH,    ctx->arnr_strength);
    if (ctx->arnr_type >= 0)
        codecctl_int(avctx, VP8E_SET_ARNR_TYPE,        ctx->arnr_type);
    codecctl_int(avctx, VP8E_SET_NOISE_SENSITIVITY, avctx->noise_reduction);
    codecctl_int(avctx, VP8E_SET_TOKEN_PARTITIONS,  av_log2(avctx->slices));
    codecctl_int(avctx, VP8E_SET_STATIC_THRESHOLD,  avctx->mb_threshold);
    codecctl_int(avctx, VP8E_SET_CQ_LEVEL,          ctx->crf);
    if (ctx->max_intra_rate >= 0)
        codecctl_int(avctx, VP8E_SET_MAX_INTRA_BITRATE_PCT, ctx->max_intra_rate);

    av_log(avctx, AV_LOG_DEBUG, "Using deadline: %d\n", ctx->deadline);

    //provide dummy value to initialize wrapper, values will be updated each _encode()
    vpx_img_wrap(&ctx->rawimg, VPX_IMG_FMT_I420, avctx->width, avctx->height, 1,
                 (unsigned char*)1);

    if (ctx->is_alpha)
        vpx_img_wrap(&ctx->rawimg_alpha, VPX_IMG_FMT_I420, avctx->width, avctx->height, 1,
                     (unsigned char*)1);

    avctx->coded_frame = avcodec_alloc_frame();
    if (!avctx->coded_frame) {
        av_log(avctx, AV_LOG_ERROR, "Error allocating coded frame\n");
        vp8_free(avctx);
        return AVERROR(ENOMEM);
    }
    return 0;
}

static inline void cx_pktcpy(struct FrameListData *dst,
                             const struct vpx_codec_cx_pkt *src,
                             const struct vpx_codec_cx_pkt *src_alpha,
                             VP8Context *ctx)
{
    dst->pts      = src->data.frame.pts;
    dst->duration = src->data.frame.duration;
    dst->flags    = src->data.frame.flags;
    dst->sz       = src->data.frame.sz;
    dst->buf      = src->data.frame.buf;
    dst->have_sse = 0;
    /* For alt-ref frame, don't store PSNR or increment frame_number */
    if (!(dst->flags & VPX_FRAME_IS_INVISIBLE)) {
        dst->frame_number = ++ctx->frame_number;
        dst->have_sse = ctx->have_sse;
        if (ctx->have_sse) {
            /* associate last-seen SSE to the frame. */
            /* Transfers ownership from ctx to dst. */
            /* WARNING! This makes the assumption that PSNR_PKT comes
               just before the frame it refers to! */
            memcpy(dst->sse, ctx->sse, sizeof(dst->sse));
            ctx->have_sse = 0;
        }
    } else {
        dst->frame_number = -1;   /* sanity marker */
    }
    if (src_alpha) {
        dst->buf_alpha = src_alpha->data.frame.buf;
        dst->sz_alpha = src_alpha->data.frame.sz;
    }
    else {
        dst->buf_alpha = NULL;
        dst->sz_alpha = 0;
    }
}

/**
 * Store coded frame information in format suitable for return from encode2().
 *
 * Write information from @a cx_frame to @a pkt
 * @return packet data size on success
 * @return a negative AVERROR on error
 */
static int storeframe(AVCodecContext *avctx, struct FrameListData *cx_frame,
                      AVPacket *pkt, AVFrame *coded_frame)
{
    int ret = ff_alloc_packet2(avctx, pkt, cx_frame->sz);
    uint8_t *side_data;
    if (ret >= 0) {
        memcpy(pkt->data, cx_frame->buf, pkt->size);
        pkt->pts = pkt->dts    = cx_frame->pts;
        coded_frame->pts       = cx_frame->pts;
        coded_frame->key_frame = !!(cx_frame->flags & VPX_FRAME_IS_KEY);

        if (coded_frame->key_frame) {
            coded_frame->pict_type = AV_PICTURE_TYPE_I;
            pkt->flags            |= AV_PKT_FLAG_KEY;
        } else
            coded_frame->pict_type = AV_PICTURE_TYPE_P;

        if (cx_frame->have_sse) {
            int i;
            /* Beware of the Y/U/V/all order! */
            coded_frame->error[0] = cx_frame->sse[1];
            coded_frame->error[1] = cx_frame->sse[2];
            coded_frame->error[2] = cx_frame->sse[3];
            coded_frame->error[3] = 0;    // alpha
            for (i = 0; i < 4; ++i) {
                avctx->error[i] += coded_frame->error[i];
            }
            cx_frame->have_sse = 0;
        }
        if (cx_frame->sz_alpha > 0) {
            side_data = av_packet_new_side_data(pkt,
                                                AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
                                                cx_frame->sz_alpha + 8);
            if(side_data == NULL) {
                av_free_packet(pkt);
                av_free(pkt);
                return AVERROR(ENOMEM);
            }
            AV_WB64(side_data, 1);
            memcpy(side_data + 8, cx_frame->buf_alpha, cx_frame->sz_alpha);
        }
    } else {
        return ret;
    }
    return pkt->size;
}

/**
 * Queue multiple output frames from the encoder, returning the front-most.
 * In cases where vpx_codec_get_cx_data() returns more than 1 frame append
 * the frame queue. Return the head frame if available.
 * @return Stored frame size
 * @return AVERROR(EINVAL) on output size error
 * @return AVERROR(ENOMEM) on coded frame queue data allocation error
 */
static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
                        AVFrame *coded_frame)
{
    VP8Context *ctx = avctx->priv_data;
    const struct vpx_codec_cx_pkt *pkt;
    const struct vpx_codec_cx_pkt *pkt_alpha = NULL;
    const void *iter = NULL;
    const void *iter_alpha = NULL;
    int size = 0;

    if (ctx->coded_frame_list) {
        struct FrameListData *cx_frame = ctx->coded_frame_list;
        /* return the leading frame if we've already begun queueing */
        size = storeframe(avctx, cx_frame, pkt_out, coded_frame);
        if (size < 0)
            return size;
        ctx->coded_frame_list = cx_frame->next;
        free_coded_frame(cx_frame);
    }

    /* consume all available output from the encoder before returning. buffers
       are only good through the next vpx_codec call */
    while ((pkt = vpx_codec_get_cx_data(&ctx->encoder, &iter)) &&
            (!ctx->is_alpha ||
             (ctx->is_alpha && (pkt_alpha = vpx_codec_get_cx_data(&ctx->encoder_alpha, &iter_alpha))))) {
        switch (pkt->kind) {
        case VPX_CODEC_CX_FRAME_PKT:
            if (!size) {
                struct FrameListData cx_frame;

                /* avoid storing the frame when the list is empty and we haven't yet
                   provided a frame for output */
                av_assert0(!ctx->coded_frame_list);
                cx_pktcpy(&cx_frame, pkt, pkt_alpha, ctx);
                size = storeframe(avctx, &cx_frame, pkt_out, coded_frame);
                if (size < 0)
                    return size;
            } else {
                struct FrameListData *cx_frame =
                    av_malloc(sizeof(struct FrameListData));

                if (!cx_frame) {
                    av_log(avctx, AV_LOG_ERROR,
                           "Frame queue element alloc failed\n");
                    return AVERROR(ENOMEM);
                }
                cx_pktcpy(cx_frame, pkt, pkt_alpha, ctx);
                cx_frame->buf = av_malloc(cx_frame->sz);

                if (!cx_frame->buf) {
                    av_log(avctx, AV_LOG_ERROR,
                           "Data buffer alloc (%zu bytes) failed\n",
                           cx_frame->sz);
                    av_free(cx_frame);
                    return AVERROR(ENOMEM);
                }
                memcpy(cx_frame->buf, pkt->data.frame.buf, pkt->data.frame.sz);
                if (ctx->is_alpha) {
                    cx_frame->buf_alpha = av_malloc(cx_frame->sz_alpha);
                    if (!cx_frame->buf_alpha) {
                        av_log(avctx, AV_LOG_ERROR,
                               "Data buffer alloc (%zu bytes) failed\n",
                               cx_frame->sz_alpha);
                        av_free(cx_frame);
                        return AVERROR(ENOMEM);
                    }
                    memcpy(cx_frame->buf_alpha, pkt_alpha->data.frame.buf, pkt_alpha->data.frame.sz);
                }
                coded_frame_add(&ctx->coded_frame_list, cx_frame);
            }
            break;
        case VPX_CODEC_STATS_PKT: {
            struct vpx_fixed_buf *stats = &ctx->twopass_stats;
            stats->buf = av_realloc_f(stats->buf, 1,
                                      stats->sz + pkt->data.twopass_stats.sz);
            if (!stats->buf) {
                av_log(avctx, AV_LOG_ERROR, "Stat buffer realloc failed\n");
                return AVERROR(ENOMEM);
            }
            memcpy((uint8_t*)stats->buf + stats->sz,
                   pkt->data.twopass_stats.buf, pkt->data.twopass_stats.sz);
            stats->sz += pkt->data.twopass_stats.sz;
            break;
        }
        case VPX_CODEC_PSNR_PKT:
            av_assert0(!ctx->have_sse);
            ctx->sse[0] = pkt->data.psnr.sse[0];
            ctx->sse[1] = pkt->data.psnr.sse[1];
            ctx->sse[2] = pkt->data.psnr.sse[2];
            ctx->sse[3] = pkt->data.psnr.sse[3];
            ctx->have_sse = 1;
            break;
        case VPX_CODEC_CUSTOM_PKT:
            //ignore unsupported/unrecognized packet types
            break;
        }
    }

    return size;
}

static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
                      const AVFrame *frame, int *got_packet)
{
    VP8Context *ctx = avctx->priv_data;
    struct vpx_image *rawimg = NULL;
    struct vpx_image *rawimg_alpha = NULL;
    int64_t timestamp = 0;
    int res, coded_size;
    vpx_enc_frame_flags_t flags = 0;

    if (frame) {
        rawimg                      = &ctx->rawimg;
        rawimg->planes[VPX_PLANE_Y] = frame->data[0];
        rawimg->planes[VPX_PLANE_U] = frame->data[1];
        rawimg->planes[VPX_PLANE_V] = frame->data[2];
        rawimg->stride[VPX_PLANE_Y] = frame->linesize[0];
        rawimg->stride[VPX_PLANE_U] = frame->linesize[1];
        rawimg->stride[VPX_PLANE_V] = frame->linesize[2];
        if (ctx->is_alpha) {
            uint8_t *u_plane, *v_plane;
            rawimg_alpha = &ctx->rawimg_alpha;
            rawimg_alpha->planes[VPX_PLANE_Y] = frame->data[3];
            u_plane = av_malloc(frame->linesize[1] * frame->height);
            memset(u_plane, 0x80, frame->linesize[1] * frame->height);
            rawimg_alpha->planes[VPX_PLANE_U] = u_plane;
            v_plane = av_malloc(frame->linesize[2] * frame->height);
            memset(v_plane, 0x80, frame->linesize[2] * frame->height);
            rawimg_alpha->planes[VPX_PLANE_V] = v_plane;
        }
        timestamp                   = frame->pts;
        if (frame->pict_type == AV_PICTURE_TYPE_I)
            flags |= VPX_EFLAG_FORCE_KF;
    }

    res = vpx_codec_encode(&ctx->encoder, rawimg, timestamp,
                           avctx->ticks_per_frame, flags, ctx->deadline);
    if (res != VPX_CODEC_OK) {
        log_encoder_error(avctx, "Error encoding frame");
        return AVERROR_INVALIDDATA;
    }

    if (ctx->is_alpha) {
        res = vpx_codec_encode(&ctx->encoder_alpha, rawimg_alpha, timestamp,
                               avctx->ticks_per_frame, flags, ctx->deadline);
        if (res != VPX_CODEC_OK) {
            log_encoder_error(avctx, "Error encoding alpha frame");
            return AVERROR_INVALIDDATA;
        }
    }

    coded_size = queue_frames(avctx, pkt, avctx->coded_frame);

    if (!frame && avctx->flags & CODEC_FLAG_PASS1) {
        unsigned int b64_size = AV_BASE64_SIZE(ctx->twopass_stats.sz);

        avctx->stats_out = av_malloc(b64_size);
        if (!avctx->stats_out) {
            av_log(avctx, AV_LOG_ERROR, "Stat buffer alloc (%d bytes) failed\n",
                   b64_size);
            return AVERROR(ENOMEM);
        }
        av_base64_encode(avctx->stats_out, b64_size, ctx->twopass_stats.buf,
                         ctx->twopass_stats.sz);
    }

    if (rawimg_alpha) {
        av_free(rawimg_alpha->planes[VPX_PLANE_U]);
        av_free(rawimg_alpha->planes[VPX_PLANE_V]);
    }

    *got_packet = !!coded_size;
    return 0;
}

#define OFFSET(x) offsetof(VP8Context, x)
#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    { "cpu-used",        "Quality/Speed ratio modifier",           OFFSET(cpu_used),        AV_OPT_TYPE_INT, {.i64 = INT_MIN}, INT_MIN, INT_MAX, VE},
    { "auto-alt-ref",    "Enable use of alternate reference "
                         "frames (2-pass only)",                   OFFSET(auto_alt_ref),    AV_OPT_TYPE_INT, {.i64 = -1},      -1,      1,       VE},
    { "lag-in-frames",   "Number of frames to look ahead for "
                         "alternate reference frame selection",    OFFSET(lag_in_frames),   AV_OPT_TYPE_INT, {.i64 = -1},      -1,      INT_MAX, VE},
    { "arnr-maxframes",  "altref noise reduction max frame count", OFFSET(arnr_max_frames), AV_OPT_TYPE_INT, {.i64 = -1},      -1,      INT_MAX, VE},
    { "arnr-strength",   "altref noise reduction filter strength", OFFSET(arnr_strength),   AV_OPT_TYPE_INT, {.i64 = -1},      -1,      INT_MAX, VE},
    { "arnr-type",       "altref noise reduction filter type",     OFFSET(arnr_type),       AV_OPT_TYPE_INT, {.i64 = -1},      -1,      INT_MAX, VE, "arnr_type"},
    { "backward",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, VE, "arnr_type" },
    { "forward",         NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 2}, 0, 0, VE, "arnr_type" },
    { "centered",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 3}, 0, 0, VE, "arnr_type" },
    { "deadline",        "Time to spend encoding, in microseconds.", OFFSET(deadline),      AV_OPT_TYPE_INT, {.i64 = VPX_DL_GOOD_QUALITY}, INT_MIN, INT_MAX, VE, "quality"},
    { "best",            NULL, 0, AV_OPT_TYPE_CONST, {.i64 = VPX_DL_BEST_QUALITY}, 0, 0, VE, "quality"},
    { "good",            NULL, 0, AV_OPT_TYPE_CONST, {.i64 = VPX_DL_GOOD_QUALITY}, 0, 0, VE, "quality"},
    { "realtime",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = VPX_DL_REALTIME},     0, 0, VE, "quality"},
    { "error-resilient", "Error resilience configuration", OFFSET(error_resilient), AV_OPT_TYPE_FLAGS, {.i64 = 0}, INT_MIN, INT_MAX, VE, "er"},
    { "max-intra-rate",  "Maximum I-frame bitrate (pct) 0=unlimited",  OFFSET(max_intra_rate),  AV_OPT_TYPE_INT,  {.i64 = -1}, -1,      INT_MAX, VE},
#ifdef VPX_ERROR_RESILIENT_DEFAULT
    { "default",         "Improve resiliency against losses of whole frames", 0, AV_OPT_TYPE_CONST, {.i64 = VPX_ERROR_RESILIENT_DEFAULT}, 0, 0, VE, "er"},
    { "partitions",      "The frame partitions are independently decodable "
                         "by the bool decoder, meaning that partitions can be decoded even "
                         "though earlier partitions have been lost. Note that intra predicition"
                         " is still done over the partition boundary.",       0, AV_OPT_TYPE_CONST, {.i64 = VPX_ERROR_RESILIENT_PARTITIONS}, 0, 0, VE, "er"},
#endif
{"speed", "", offsetof(VP8Context, cpu_used), AV_OPT_TYPE_INT, {.i64 = 3}, -16, 16, VE},
{"quality", "", offsetof(VP8Context, deadline), AV_OPT_TYPE_INT, {.i64 = VPX_DL_GOOD_QUALITY}, INT_MIN, INT_MAX, VE, "quality"},
{"vp8flags", "", offsetof(VP8Context, flags), FF_OPT_TYPE_FLAGS, {.i64 = 0}, 0, UINT_MAX, VE, "flags"},
{"error_resilient", "enable error resilience", 0, FF_OPT_TYPE_CONST, {.dbl = VP8F_ERROR_RESILIENT}, INT_MIN, INT_MAX, VE, "flags"},
{"altref", "enable use of alternate reference frames (VP8/2-pass only)", 0, FF_OPT_TYPE_CONST, {.dbl = VP8F_AUTO_ALT_REF}, INT_MIN, INT_MAX, VE, "flags"},
{"arnr_max_frames", "altref noise reduction max frame count", offsetof(VP8Context, arnr_max_frames), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 15, VE},
{"arnr_strength", "altref noise reduction filter strength", offsetof(VP8Context, arnr_strength), AV_OPT_TYPE_INT, {.i64 = 3}, 0, 6, VE},
{"arnr_type", "altref noise reduction filter type", offsetof(VP8Context, arnr_type), AV_OPT_TYPE_INT, {.i64 = 3}, 1, 3, VE},
{"rc_lookahead", "Number of frames to look ahead for alternate reference frame selection", offsetof(VP8Context, lag_in_frames), AV_OPT_TYPE_INT, {.i64 = 25}, 0, 25, VE},
    { "crf",              "Select the quality for constant quality mode", offsetof(VP8Context, crf), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 63, VE },
    { NULL }
};

static const AVCodecDefault defaults[] = {
    { "qmin",             "-1" },
    { "qmax",             "-1" },
    { "g",                "-1" },
    { "keyint_min",       "-1" },
    { NULL },
};

#if CONFIG_LIBVPX_VP8_ENCODER
static av_cold int vp8_init(AVCodecContext *avctx)
{
    return vpx_init(avctx, &vpx_codec_vp8_cx_algo);
}

static const AVClass class_vp8 = {
    .class_name = "libvpx-vp8 encoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_libvpx_vp8_encoder = {
    .name           = "libvpx",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_VP8,
    .priv_data_size = sizeof(VP8Context),
    .init           = vp8_init,
    .encode2        = vp8_encode,
    .close          = vp8_free,
    .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_AUTO_THREADS,
    .pix_fmts       = (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_NONE },
    .long_name      = NULL_IF_CONFIG_SMALL("libvpx VP8"),
    .priv_class     = &class_vp8,
    .defaults       = defaults,
};
#endif /* CONFIG_LIBVPX_VP8_ENCODER */

#if CONFIG_LIBVPX_VP9_ENCODER
static av_cold int vp9_init(AVCodecContext *avctx)
{
    return vpx_init(avctx, &vpx_codec_vp9_cx_algo);
}

static const AVClass class_vp9 = {
    .class_name = "libvpx-vp9 encoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_libvpx_vp9_encoder = {
    .name           = "libvpx-vp9",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_VP9,
    .priv_data_size = sizeof(VP8Context),
    .init           = vp9_init,
    .encode2        = vp8_encode,
    .close          = vp8_free,
    .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_AUTO_THREADS | CODEC_CAP_EXPERIMENTAL,
    .pix_fmts       = (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE },
    .long_name      = NULL_IF_CONFIG_SMALL("libvpx VP9"),
    .priv_class     = &class_vp9,
    .defaults       = defaults,
};
#endif /* CONFIG_LIBVPX_VP9_ENCODER */