libwebpenc.c

/*
 * WebP encoding support via libwebp
 * Copyright (c) 2013 Justin Ruggles <justin.ruggles@gmail.com>
 *
 * 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
 * WebP encoder using libwebp (WebPEncode API)
 */

#include "libwebpenc_common.h"

typedef LibWebPContextCommon LibWebPContext;

static av_cold int libwebp_encode_init(AVCodecContext *avctx)
{
    return ff_libwebp_encode_init_common(avctx);
}

static int libwebp_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                                const AVFrame *frame, int *got_packet)
{
    LibWebPContext *s  = avctx->priv_data;
    WebPPicture *pic = NULL;
    AVFrame *alt_frame = NULL;
    WebPMemoryWriter mw = { 0 };

    int ret = ff_libwebp_get_frame(avctx, s, frame, &alt_frame, &pic);
    if (ret < 0)
        goto end;

    WebPMemoryWriterInit(&mw);
    pic->custom_ptr = &mw;
    pic->writer     = WebPMemoryWrite;

    ret = WebPEncode(&s->config, pic);
    if (!ret) {
        av_log(avctx, AV_LOG_ERROR, "WebPEncode() failed with error: %d\n",
               pic->error_code);
        ret = ff_libwebp_error_to_averror(pic->error_code);
        goto end;
    }

    ret = ff_alloc_packet2(avctx, pkt, mw.size, mw.size);
    if (ret < 0)
        goto end;
    memcpy(pkt->data, mw.mem, mw.size);

    pkt->flags |= AV_PKT_FLAG_KEY;
    *got_packet = 1;

end:
#if (WEBP_ENCODER_ABI_VERSION > 0x0203)
    WebPMemoryWriterClear(&mw);
#else
    free(mw.mem); /* must use free() according to libwebp documentation */
#endif
    WebPPictureFree(pic);
    av_freep(&pic);
    av_frame_free(&alt_frame);

    return ret;
}

static int libwebp_encode_close(AVCodecContext *avctx)
{
    LibWebPContextCommon *s  = avctx->priv_data;
    av_frame_free(&s->ref);

    return 0;
}

static const AVClass class = {
    .class_name = "libwebp",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_libwebp_encoder = {
    .name           = "libwebp",
    .long_name      = NULL_IF_CONFIG_SMALL("libwebp WebP image"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_WEBP,
    .priv_data_size = sizeof(LibWebPContext),
    .init           = libwebp_encode_init,
    .encode2        = libwebp_encode_frame,
    .close          = libwebp_encode_close,
    .pix_fmts       = (const enum AVPixelFormat[]) {
        AV_PIX_FMT_RGB32,
        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVA420P,
        AV_PIX_FMT_NONE
    },
    .priv_class     = &class,
    .defaults       = libwebp_defaults,
    .wrapper_name   = "libwebp",
};