FFmpeg/libavcodec/options.c

/*
 * Copyright (c) 2001 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Options definition for AVCodecContext.
 */

#include "avcodec.h"
#include "internal.h"
#include "libavutil/avassert.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include <float.h>              /* FLT_MIN, FLT_MAX */
#include <string.h>

#include "options_table.h"

static const char* context_to_name(void* ptr) {
    AVCodecContext *avc= ptr;

    if(avc && avc->codec && avc->codec->name)
        return avc->codec->name;
    else
        return "NULL";
}

static void *codec_child_next(void *obj, void *prev)
{
    AVCodecContext *s = obj;
    if (!prev && s->codec && s->codec->priv_class && s->priv_data)
        return s->priv_data;
    return NULL;
}

static const AVClass *codec_child_class_next(const AVClass *prev)
{
    AVCodec *c = NULL;

    /* find the codec that corresponds to prev */
    while (prev && (c = av_codec_next(c)))
        if (c->priv_class == prev)
            break;

    /* find next codec with priv options */
    while (c = av_codec_next(c))
        if (c->priv_class)
            return c->priv_class;
    return NULL;
}

static const AVClass av_codec_context_class = {
    .class_name              = "AVCodecContext",
    .item_name               = context_to_name,
    .option                  = avcodec_options,
    .version                 = LIBAVUTIL_VERSION_INT,
    .log_level_offset_offset = offsetof(AVCodecContext, log_level_offset),
    .child_next              = codec_child_next,
    .child_class_next        = codec_child_class_next,
};

int avcodec_get_context_defaults3(AVCodecContext *s, const AVCodec *codec)
{
    memset(s, 0, sizeof(AVCodecContext));

    s->av_class = &av_codec_context_class;

    s->codec_type = codec ? codec->type : AVMEDIA_TYPE_UNKNOWN;
    s->codec      = codec;
    av_opt_set_defaults(s);

    s->time_base           = (AVRational){0,1};
    s->get_buffer2         = avcodec_default_get_buffer2;
    s->get_format          = avcodec_default_get_format;
    s->execute             = avcodec_default_execute;
    s->execute2            = avcodec_default_execute2;
    s->sample_aspect_ratio = (AVRational){0,1};
    s->pix_fmt             = AV_PIX_FMT_NONE;
    s->sample_fmt          = AV_SAMPLE_FMT_NONE;

    s->reordered_opaque    = AV_NOPTS_VALUE;
    if(codec && codec->priv_data_size){
        if(!s->priv_data){
            s->priv_data= av_mallocz(codec->priv_data_size);
            if (!s->priv_data) {
                return AVERROR(ENOMEM);
            }
        }
        if(codec->priv_class){
            *(const AVClass**)s->priv_data = codec->priv_class;
            av_opt_set_defaults(s->priv_data);
        }
    }
    if (codec && codec->defaults) {
        int ret;
        const AVCodecDefault *d = codec->defaults;
        while (d->key) {
            ret = av_opt_set(s, d->key, d->value, 0);
            av_assert0(ret >= 0);
            d++;
        }
    }
    return 0;
}

AVCodecContext *avcodec_alloc_context3(const AVCodec *codec)
{
    AVCodecContext *avctx= av_malloc(sizeof(AVCodecContext));

    if(avctx==NULL) return NULL;

    if(avcodec_get_context_defaults3(avctx, codec) < 0){
        av_free(avctx);
        return NULL;
    }

    return avctx;
}

void avcodec_free_context(AVCodecContext **pavctx)
{
    AVCodecContext *avctx = *pavctx;

    if (!avctx)
        return;

    avcodec_close(avctx);

    av_freep(&avctx->extradata);
    av_freep(&avctx->subtitle_header);

    av_freep(pavctx);
}

int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src)
{
    const AVCodec *orig_codec = dest->codec;
    uint8_t *orig_priv_data = dest->priv_data;

    if (avcodec_is_open(dest)) { // check that the dest context is uninitialized
        av_log(dest, AV_LOG_ERROR,
               "Tried to copy AVCodecContext %p into already-initialized %p\n",
               src, dest);
        return AVERROR(EINVAL);
    }
    memcpy(dest, src, sizeof(*dest));

    dest->priv_data       = orig_priv_data;
    dest->codec           = orig_codec;

    /* set values specific to opened codecs back to their default state */
    dest->slice_offset    = NULL;
    dest->hwaccel         = NULL;
    dest->internal        = NULL;

    /* reallocate values that should be allocated separately */
    dest->rc_eq           = NULL;
    dest->extradata       = NULL;
    dest->intra_matrix    = NULL;
    dest->inter_matrix    = NULL;
    dest->rc_override     = NULL;
    dest->subtitle_header = NULL;
    if (src->rc_eq) {
        dest->rc_eq = av_strdup(src->rc_eq);
        if (!dest->rc_eq)
            return AVERROR(ENOMEM);
    }

#define alloc_and_copy_or_fail(obj, size, pad) \
    if (src->obj && size > 0) { \
        dest->obj = av_malloc(size + pad); \
        if (!dest->obj) \
            goto fail; \
        memcpy(dest->obj, src->obj, size); \
        if (pad) \
            memset(((uint8_t *) dest->obj) + size, 0, pad); \
    }
    alloc_and_copy_or_fail(extradata,    src->extradata_size,
                           FF_INPUT_BUFFER_PADDING_SIZE);
    alloc_and_copy_or_fail(intra_matrix, 64 * sizeof(int16_t), 0);
    alloc_and_copy_or_fail(inter_matrix, 64 * sizeof(int16_t), 0);
    alloc_and_copy_or_fail(rc_override,  src->rc_override_count * sizeof(*src->rc_override), 0);
    alloc_and_copy_or_fail(subtitle_header, src->subtitle_header_size, 0);
    dest->subtitle_header_size = src->subtitle_header_size;
#undef alloc_and_copy_or_fail

    return 0;

fail:
    av_freep(&dest->rc_override);
    av_freep(&dest->intra_matrix);
    av_freep(&dest->inter_matrix);
    av_freep(&dest->extradata);
    av_freep(&dest->rc_eq);
    return AVERROR(ENOMEM);
}

const AVClass *avcodec_get_class(void)
{
    return &av_codec_context_class;
}