utils.c

/*
 * utils for libavcodec
 * 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
 * utils.
 */

#include "config.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/crc.h"
#include "libavutil/frame.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/samplefmt.h"
#include "libavutil/dict.h"
#include "avcodec.h"
#include "dsputil.h"
#include "libavutil/opt.h"
#include "thread.h"
#include "internal.h"
#include "bytestream.h"
#include <stdlib.h>
#include <stdarg.h>
#include <limits.h>
#include <float.h>

static int volatile entangled_thread_counter = 0;
static int (*ff_lockmgr_cb)(void **mutex, enum AVLockOp op);
static void *codec_mutex;
static void *avformat_mutex;

void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
{
    if (min_size < *size)
        return ptr;

    min_size = FFMAX(17 * min_size / 16 + 32, min_size);

    ptr = av_realloc(ptr, min_size);
    /* we could set this to the unmodified min_size but this is safer
     * if the user lost the ptr and uses NULL now
     */
    if (!ptr)
        min_size = 0;

    *size = min_size;

    return ptr;
}

void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
{
    void **p = ptr;
    if (min_size < *size)
        return;
    min_size = FFMAX(17 * min_size / 16 + 32, min_size);
    av_free(*p);
    *p = av_malloc(min_size);
    if (!*p)
        min_size = 0;
    *size = min_size;
}

void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size)
{
    void **p = ptr;
    if (min_size > SIZE_MAX - FF_INPUT_BUFFER_PADDING_SIZE) {
        av_freep(p);
        *size = 0;
        return;
    }
    av_fast_malloc(p, size, min_size + FF_INPUT_BUFFER_PADDING_SIZE);
    if (*size)
        memset((uint8_t *)*p + min_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
}

/* encoder management */
static AVCodec *first_avcodec = NULL;

AVCodec *av_codec_next(const AVCodec *c)
{
    if (c)
        return c->next;
    else
        return first_avcodec;
}

static void avcodec_init(void)
{
    static int initialized = 0;

    if (initialized != 0)
        return;
    initialized = 1;

    ff_dsputil_static_init();
}

int av_codec_is_encoder(const AVCodec *codec)
{
    return codec && (codec->encode_sub || codec->encode2);
}

int av_codec_is_decoder(const AVCodec *codec)
{
    return codec && codec->decode;
}

void avcodec_register(AVCodec *codec)
{
    AVCodec **p;
    avcodec_init();
    p = &first_avcodec;
    while (*p != NULL)
        p = &(*p)->next;
    *p          = codec;
    codec->next = NULL;

    if (codec->init_static_data)
        codec->init_static_data(codec);
}

unsigned avcodec_get_edge_width(void)
{
    return EDGE_WIDTH;
}

void avcodec_set_dimensions(AVCodecContext *s, int width, int height)
{
    s->coded_width  = width;
    s->coded_height = height;
    s->width        = width;
    s->height       = height;
}

#if (ARCH_ARM && HAVE_NEON) || ARCH_PPC || HAVE_MMX
#   define STRIDE_ALIGN 16
#else
#   define STRIDE_ALIGN 8
#endif

void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
                               int linesize_align[AV_NUM_DATA_POINTERS])
{
    int i;
    int w_align = 1;
    int h_align = 1;

    switch (s->pix_fmt) {
    case AV_PIX_FMT_YUV420P:
    case AV_PIX_FMT_YUYV422:
    case AV_PIX_FMT_UYVY422:
    case AV_PIX_FMT_YUV422P:
    case AV_PIX_FMT_YUV440P:
    case AV_PIX_FMT_YUV444P:
    case AV_PIX_FMT_GBRP:
    case AV_PIX_FMT_GRAY8:
    case AV_PIX_FMT_GRAY16BE:
    case AV_PIX_FMT_GRAY16LE:
    case AV_PIX_FMT_YUVJ420P:
    case AV_PIX_FMT_YUVJ422P:
    case AV_PIX_FMT_YUVJ440P:
    case AV_PIX_FMT_YUVJ444P:
    case AV_PIX_FMT_YUVA420P:
    case AV_PIX_FMT_YUVA422P:
    case AV_PIX_FMT_YUVA444P:
    case AV_PIX_FMT_YUV420P9LE:
    case AV_PIX_FMT_YUV420P9BE:
    case AV_PIX_FMT_YUV420P10LE:
    case AV_PIX_FMT_YUV420P10BE:
    case AV_PIX_FMT_YUV422P9LE:
    case AV_PIX_FMT_YUV422P9BE:
    case AV_PIX_FMT_YUV422P10LE:
    case AV_PIX_FMT_YUV422P10BE:
    case AV_PIX_FMT_YUV444P9LE:
    case AV_PIX_FMT_YUV444P9BE:
    case AV_PIX_FMT_YUV444P10LE:
    case AV_PIX_FMT_YUV444P10BE:
    case AV_PIX_FMT_GBRP9LE:
    case AV_PIX_FMT_GBRP9BE:
    case AV_PIX_FMT_GBRP10LE:
    case AV_PIX_FMT_GBRP10BE:
        w_align = 16; //FIXME assume 16 pixel per macroblock
        h_align = 16 * 2; // interlaced needs 2 macroblocks height
        break;
    case AV_PIX_FMT_YUV411P:
    case AV_PIX_FMT_UYYVYY411:
        w_align = 32;
        h_align = 8;
        break;
    case AV_PIX_FMT_YUV410P:
        if (s->codec_id == AV_CODEC_ID_SVQ1) {
            w_align = 64;
            h_align = 64;
        }
    case AV_PIX_FMT_RGB555:
        if (s->codec_id == AV_CODEC_ID_RPZA) {
            w_align = 4;
            h_align = 4;
        }
    case AV_PIX_FMT_PAL8:
    case AV_PIX_FMT_BGR8:
    case AV_PIX_FMT_RGB8:
        if (s->codec_id == AV_CODEC_ID_SMC) {
            w_align = 4;
            h_align = 4;
        }
        break;
    case AV_PIX_FMT_BGR24:
        if ((s->codec_id == AV_CODEC_ID_MSZH) ||
            (s->codec_id == AV_CODEC_ID_ZLIB)) {
            w_align = 4;
            h_align = 4;
        }
        break;
    default:
        w_align = 1;
        h_align = 1;
        break;
    }

    *width  = FFALIGN(*width, w_align);
    *height = FFALIGN(*height, h_align);
    if (s->codec_id == AV_CODEC_ID_H264)
        // some of the optimized chroma MC reads one line too much
        *height += 2;

    for (i = 0; i < 4; i++)
        linesize_align[i] = STRIDE_ALIGN;
}

void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->pix_fmt);
    int chroma_shift = desc->log2_chroma_w;
    int linesize_align[AV_NUM_DATA_POINTERS];
    int align;

    avcodec_align_dimensions2(s, width, height, linesize_align);
    align               = FFMAX(linesize_align[0], linesize_align[3]);
    linesize_align[1] <<= chroma_shift;
    linesize_align[2] <<= chroma_shift;
    align               = FFMAX3(align, linesize_align[1], linesize_align[2]);
    *width              = FFALIGN(*width, align);
}

int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
                             enum AVSampleFormat sample_fmt, const uint8_t *buf,
                             int buf_size, int align)
{
    int ch, planar, needed_size, ret = 0;

    needed_size = av_samples_get_buffer_size(NULL, nb_channels,
                                             frame->nb_samples, sample_fmt,
                                             align);
    if (buf_size < needed_size)
        return AVERROR(EINVAL);

    planar = av_sample_fmt_is_planar(sample_fmt);
    if (planar && nb_channels > AV_NUM_DATA_POINTERS) {
        if (!(frame->extended_data = av_mallocz(nb_channels *
                                                sizeof(*frame->extended_data))))
            return AVERROR(ENOMEM);
    } else {
        frame->extended_data = frame->data;
    }

    if ((ret = av_samples_fill_arrays(frame->extended_data, &frame->linesize[0],
                                      buf, nb_channels, frame->nb_samples,
                                      sample_fmt, align)) < 0) {
        if (frame->extended_data != frame->data)
            av_free(frame->extended_data);
        return ret;
    }
    if (frame->extended_data != frame->data) {
        for (ch = 0; ch < AV_NUM_DATA_POINTERS; ch++)
            frame->data[ch] = frame->extended_data[ch];
    }

    return ret;
}

static int update_frame_pool(AVCodecContext *avctx, AVFrame *frame)
{
    FramePool *pool = avctx->internal->pool;
    int i, ret;

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO: {
        AVPicture picture;
        int size[4] = { 0 };
        int w = frame->width;
        int h = frame->height;
        int tmpsize, unaligned;

        if (pool->format == frame->format &&
            pool->width == frame->width && pool->height == frame->height)
            return 0;

        avcodec_align_dimensions2(avctx, &w, &h, pool->stride_align);

        if (!(avctx->flags & CODEC_FLAG_EMU_EDGE)) {
            w += EDGE_WIDTH * 2;
            h += EDGE_WIDTH * 2;
        }

        do {
            // NOTE: do not align linesizes individually, this breaks e.g. assumptions
            // that linesize[0] == 2*linesize[1] in the MPEG-encoder for 4:2:2
            av_image_fill_linesizes(picture.linesize, avctx->pix_fmt, w);
            // increase alignment of w for next try (rhs gives the lowest bit set in w)
            w += w & ~(w - 1);

            unaligned = 0;
            for (i = 0; i < 4; i++)
                unaligned |= picture.linesize[i] % pool->stride_align[i];
        } while (unaligned);

        tmpsize = av_image_fill_pointers(picture.data, avctx->pix_fmt, h,
                                         NULL, picture.linesize);
        if (tmpsize < 0)
            return -1;

        for (i = 0; i < 3 && picture.data[i + 1]; i++)
            size[i] = picture.data[i + 1] - picture.data[i];
        size[i] = tmpsize - (picture.data[i] - picture.data[0]);

        for (i = 0; i < 4; i++) {
            av_buffer_pool_uninit(&pool->pools[i]);
            pool->linesize[i] = picture.linesize[i];
            if (size[i]) {
                pool->pools[i] = av_buffer_pool_init(size[i] + 16, NULL);
                if (!pool->pools[i]) {
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
            }
        }
        pool->format = frame->format;
        pool->width  = frame->width;
        pool->height = frame->height;

        break;
        }
    case AVMEDIA_TYPE_AUDIO: {
        int ch     = av_get_channel_layout_nb_channels(frame->channel_layout);
        int planar = av_sample_fmt_is_planar(frame->format);
        int planes = planar ? ch : 1;

        if (pool->format == frame->format && pool->planes == planes &&
            pool->channels == ch && frame->nb_samples == pool->samples)
            return 0;

        av_buffer_pool_uninit(&pool->pools[0]);
        ret = av_samples_get_buffer_size(&pool->linesize[0], ch,
                                         frame->nb_samples, frame->format, 0);
        if (ret < 0)
            goto fail;

        pool->pools[0] = av_buffer_pool_init(pool->linesize[0], NULL);
        if (!pool->pools[0]) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

        pool->format     = frame->format;
        pool->planes     = planes;
        pool->channels   = ch;
        pool->samples = frame->nb_samples;
        break;
        }
    default: av_assert0(0);
    }
    return 0;
fail:
    for (i = 0; i < 4; i++)
        av_buffer_pool_uninit(&pool->pools[i]);
    pool->format = -1;
    pool->planes = pool->channels = pool->samples = 0;
    pool->width  = pool->height = 0;
    return ret;
}

static int audio_get_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    FramePool *pool = avctx->internal->pool;
    int planes = pool->planes;
    int i;

    frame->linesize[0] = pool->linesize[0];

    if (planes > AV_NUM_DATA_POINTERS) {
        frame->extended_data = av_mallocz(planes * sizeof(*frame->extended_data));
        frame->nb_extended_buf = planes - AV_NUM_DATA_POINTERS;
        frame->extended_buf  = av_mallocz(frame->nb_extended_buf *
                                          sizeof(*frame->extended_buf));
        if (!frame->extended_data || !frame->extended_buf) {
            av_freep(&frame->extended_data);
            av_freep(&frame->extended_buf);
            return AVERROR(ENOMEM);
        }
    } else
        frame->extended_data = frame->data;

    for (i = 0; i < FFMIN(planes, AV_NUM_DATA_POINTERS); i++) {
        frame->buf[i] = av_buffer_pool_get(pool->pools[0]);
        if (!frame->buf[i])
            goto fail;
        frame->extended_data[i] = frame->data[i] = frame->buf[i]->data;
    }
    for (i = 0; i < frame->nb_extended_buf; i++) {
        frame->extended_buf[i] = av_buffer_pool_get(pool->pools[0]);
        if (!frame->extended_buf[i])
            goto fail;
        frame->extended_data[i + AV_NUM_DATA_POINTERS] = frame->extended_buf[i]->data;
    }

    if (avctx->debug & FF_DEBUG_BUFFERS)
        av_log(avctx, AV_LOG_DEBUG, "default_get_buffer called on frame %p", frame);

    return 0;
fail:
    av_frame_unref(frame);
    return AVERROR(ENOMEM);
}

static int video_get_buffer(AVCodecContext *s, AVFrame *pic)
{
    FramePool *pool = s->internal->pool;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pic->format);
    int pixel_size = desc->comp[0].step_minus1 + 1;
    int h_chroma_shift, v_chroma_shift;
    int i;

    if (pic->data[0] != NULL) {
        av_log(s, AV_LOG_ERROR, "pic->data[0]!=NULL in avcodec_default_get_buffer\n");
        return -1;
    }

    memset(pic->data, 0, sizeof(pic->data));
    pic->extended_data = pic->data;

    av_pix_fmt_get_chroma_sub_sample(s->pix_fmt, &h_chroma_shift, &v_chroma_shift);

    for (i = 0; i < 4 && pool->pools[i]; i++) {
        const int h_shift = i == 0 ? 0 : h_chroma_shift;
        const int v_shift = i == 0 ? 0 : v_chroma_shift;

        pic->linesize[i] = pool->linesize[i];

        pic->buf[i] = av_buffer_pool_get(pool->pools[i]);
        if (!pic->buf[i])
            goto fail;

        // no edge if EDGE EMU or not planar YUV
        if ((s->flags & CODEC_FLAG_EMU_EDGE) || !pool->pools[2])
            pic->data[i] = pic->buf[i]->data;
        else {
            pic->data[i] = pic->buf[i]->data +
                FFALIGN((pic->linesize[i] * EDGE_WIDTH >> v_shift) +
                        (pixel_size * EDGE_WIDTH >> h_shift), pool->stride_align[i]);
        }
    }
    for (; i < AV_NUM_DATA_POINTERS; i++) {
        pic->data[i] = NULL;
        pic->linesize[i] = 0;
    }
    if (pic->data[1] && !pic->data[2])
        avpriv_set_systematic_pal2((uint32_t *)pic->data[1], s->pix_fmt);

    if (s->debug & FF_DEBUG_BUFFERS)
        av_log(s, AV_LOG_DEBUG, "default_get_buffer called on pic %p\n", pic);

    return 0;
fail:
    av_frame_unref(pic);
    return AVERROR(ENOMEM);
}

int avcodec_default_get_buffer2(AVCodecContext *avctx, AVFrame *frame, int flags)
{
    int ret;

    if ((ret = update_frame_pool(avctx, frame)) < 0)
        return ret;

#if FF_API_GET_BUFFER
    frame->type = FF_BUFFER_TYPE_INTERNAL;
#endif

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        return video_get_buffer(avctx, frame);
    case AVMEDIA_TYPE_AUDIO:
        return audio_get_buffer(avctx, frame);
    default:
        return -1;
    }
}

#if FF_API_GET_BUFFER
int avcodec_default_get_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    return avcodec_default_get_buffer2(avctx, frame, 0);
}

typedef struct CompatReleaseBufPriv {
    AVCodecContext avctx;
    AVFrame frame;
} CompatReleaseBufPriv;

static void compat_free_buffer(void *opaque, uint8_t *data)
{
    CompatReleaseBufPriv *priv = opaque;
    priv->avctx.release_buffer(&priv->avctx, &priv->frame);
    av_freep(&priv);
}

static void compat_release_buffer(void *opaque, uint8_t *data)
{
    AVBufferRef *buf = opaque;
    av_buffer_unref(&buf);
}
#endif

int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
{
    int ret;

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        frame->width               = avctx->width;
        frame->height              = avctx->height;
        frame->format              = avctx->pix_fmt;
        frame->sample_aspect_ratio = avctx->sample_aspect_ratio;

        if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
            return ret;
        break;
    case AVMEDIA_TYPE_AUDIO:
        frame->sample_rate    = avctx->sample_rate;
        frame->format         = avctx->sample_fmt;
        frame->channel_layout = avctx->channel_layout;
        break;
    default: return AVERROR(EINVAL);
    }

    frame->pkt_pts = avctx->pkt ? avctx->pkt->pts : AV_NOPTS_VALUE;
    frame->reordered_opaque = avctx->reordered_opaque;

#if FF_API_GET_BUFFER
    /*
     * Wrap an old get_buffer()-allocated buffer in an bunch of AVBuffers.
     * We wrap each plane in its own AVBuffer. Each of those has a reference to
     * a dummy AVBuffer as its private data, unreffing it on free.
     * When all the planes are freed, the dummy buffer's free callback calls
     * release_buffer().
     */
    if (avctx->get_buffer) {
        CompatReleaseBufPriv *priv = NULL;
        AVBufferRef *dummy_buf = NULL;
        int planes, i, ret;

        if (flags & AV_GET_BUFFER_FLAG_REF)
            frame->reference    = 1;

        ret = avctx->get_buffer(avctx, frame);
        if (ret < 0)
            return ret;

        /* return if the buffers are already set up
         * this would happen e.g. when a custom get_buffer() calls
         * avcodec_default_get_buffer
         */
        if (frame->buf[0])
            return 0;

        priv = av_mallocz(sizeof(*priv));
        if (!priv) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        priv->avctx = *avctx;
        priv->frame = *frame;

        dummy_buf = av_buffer_create(NULL, 0, compat_free_buffer, priv, 0);
        if (!dummy_buf) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

#define WRAP_PLANE(ref_out, data, data_size)                            \
do {                                                                    \
    AVBufferRef *dummy_ref = av_buffer_ref(dummy_buf);                  \
    if (!dummy_ref) {                                                   \
        ret = AVERROR(ENOMEM);                                          \
        goto fail;                                                      \
    }                                                                   \
    ref_out = av_buffer_create(data, data_size, compat_release_buffer,  \
                               dummy_ref, 0);                           \
    if (!ref_out) {                                                     \
        av_frame_unref(frame);                                          \
        ret = AVERROR(ENOMEM);                                          \
        goto fail;                                                      \
    }                                                                   \
} while (0)

        if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
            const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);

            if (!desc) {
                ret = AVERROR(EINVAL);
                goto fail;
            }
            planes = (desc->flags & PIX_FMT_PLANAR) ? desc->nb_components : 1;

            for (i = 0; i < planes; i++) {
                int h_shift    = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
                int plane_size = (frame->width >> h_shift) * frame->linesize[i];

                WRAP_PLANE(frame->buf[i], frame->data[i], plane_size);
            }
        } else {
            int planar = av_sample_fmt_is_planar(frame->format);
            planes = planar ? avctx->channels : 1;

            if (planes > FF_ARRAY_ELEMS(frame->buf)) {
                frame->nb_extended_buf = planes - FF_ARRAY_ELEMS(frame->buf);
                frame->extended_buf = av_malloc(sizeof(*frame->extended_buf) *
                                                frame->nb_extended_buf);
                if (!frame->extended_buf) {
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
            }

            for (i = 0; i < FFMIN(planes, FF_ARRAY_ELEMS(frame->buf)); i++)
                WRAP_PLANE(frame->buf[i], frame->extended_data[i], frame->linesize[0]);

            for (i = 0; i < planes - FF_ARRAY_ELEMS(frame->buf); i++)
                WRAP_PLANE(frame->extended_buf[i],
                           frame->extended_data[i + FF_ARRAY_ELEMS(frame->buf)],
                           frame->linesize[0]);
        }

        av_buffer_unref(&dummy_buf);

        return 0;

fail:
        avctx->release_buffer(avctx, frame);
        av_freep(&priv);
        av_buffer_unref(&dummy_buf);
        return ret;
    }
#endif

    return avctx->get_buffer2(avctx, frame, flags);
}

int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    AVFrame tmp;
    int ret;

    av_assert0(avctx->codec_type == AVMEDIA_TYPE_VIDEO);

    if (!frame->data[0])
        return ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);

    if (av_frame_is_writable(frame))
        return 0;

    av_frame_move_ref(&tmp, frame);

    ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);
    if (ret < 0) {
        av_frame_unref(&tmp);
        return ret;
    }

    av_image_copy(frame->data, frame->linesize, tmp.data, tmp.linesize,
                  frame->format, frame->width, frame->height);

    av_frame_unref(&tmp);

    return 0;
}

#if FF_API_GET_BUFFER
void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic)
{
    av_frame_unref(pic);
}

int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic)
{
    av_assert0(0);
}
#endif

int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2), void *arg, int *ret, int count, int size)
{
    int i;

    for (i = 0; i < count; i++) {
        int r = func(c, (char *)arg + i * size);
        if (ret)
            ret[i] = r;
    }
    return 0;
}

int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int jobnr, int threadnr), void *arg, int *ret, int count)
{
    int i;

    for (i = 0; i < count; i++) {
        int r = func(c, arg, i, 0);
        if (ret)
            ret[i] = r;
    }
    return 0;
}

static int is_hwaccel_pix_fmt(enum AVPixelFormat pix_fmt)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    return desc->flags & PIX_FMT_HWACCEL;
}

enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat *fmt)
{
    while (*fmt != AV_PIX_FMT_NONE && is_hwaccel_pix_fmt(*fmt))
        ++fmt;
    return fmt[0];
}

void avcodec_get_frame_defaults(AVFrame *frame)
{
    if (frame->extended_data != frame->data)
        av_freep(&frame->extended_data);

    memset(frame, 0, sizeof(AVFrame));

    frame->pts                 = AV_NOPTS_VALUE;
    frame->key_frame           = 1;
    frame->sample_aspect_ratio = (AVRational) {0, 1 };
    frame->format              = -1; /* unknown */
    frame->extended_data       = frame->data;
}

AVFrame *avcodec_alloc_frame(void)
{
    AVFrame *frame = av_mallocz(sizeof(AVFrame));

    if (frame == NULL)
        return NULL;

    avcodec_get_frame_defaults(frame);

    return frame;
}

void avcodec_free_frame(AVFrame **frame)
{
    AVFrame *f;

    if (!frame || !*frame)
        return;

    f = *frame;

    if (f->extended_data != f->data)
        av_freep(&f->extended_data);

    av_freep(frame);
}

int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
{
    int ret = 0;
    AVDictionary *tmp = NULL;

    if (avcodec_is_open(avctx))
        return 0;

    if ((!codec && !avctx->codec)) {
        av_log(avctx, AV_LOG_ERROR, "No codec provided to avcodec_open2().\n");
        return AVERROR(EINVAL);
    }
    if ((codec && avctx->codec && codec != avctx->codec)) {
        av_log(avctx, AV_LOG_ERROR, "This AVCodecContext was allocated for %s, "
                                    "but %s passed to avcodec_open2().\n", avctx->codec->name, codec->name);
        return AVERROR(EINVAL);
    }
    if (!codec)
        codec = avctx->codec;

    if (avctx->extradata_size < 0 || avctx->extradata_size >= FF_MAX_EXTRADATA_SIZE)
        return AVERROR(EINVAL);

    if (options)
        av_dict_copy(&tmp, *options, 0);

    /* If there is a user-supplied mutex locking routine, call it. */
    if (ff_lockmgr_cb) {
        if ((*ff_lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
            return -1;
    }

    entangled_thread_counter++;
    if (entangled_thread_counter != 1) {
        av_log(avctx, AV_LOG_ERROR, "insufficient thread locking around avcodec_open/close()\n");
        ret = -1;
        goto end;
    }

    avctx->internal = av_mallocz(sizeof(AVCodecInternal));
    if (!avctx->internal) {
        ret = AVERROR(ENOMEM);
        goto end;
    }

    avctx->internal->pool = av_mallocz(sizeof(*avctx->internal->pool));
    if (!avctx->internal->pool) {
        ret = AVERROR(ENOMEM);
        goto free_and_end;
    }

    if (codec->priv_data_size > 0) {
        if (!avctx->priv_data) {
            avctx->priv_data = av_mallocz(codec->priv_data_size);
            if (!avctx->priv_data) {
                ret = AVERROR(ENOMEM);
                goto end;
            }
            if (codec->priv_class) {
                *(const AVClass **)avctx->priv_data = codec->priv_class;
                av_opt_set_defaults(avctx->priv_data);
            }
        }
        if (codec->priv_class && (ret = av_opt_set_dict(avctx->priv_data, &tmp)) < 0)
            goto free_and_end;
    } else {
        avctx->priv_data = NULL;
    }
    if ((ret = av_opt_set_dict(avctx, &tmp)) < 0)
        goto free_and_end;

    if (avctx->coded_width && avctx->coded_height)
        avcodec_set_dimensions(avctx, avctx->coded_width, avctx->coded_height);
    else if (avctx->width && avctx->height)
        avcodec_set_dimensions(avctx, avctx->width, avctx->height);

    if ((avctx->coded_width || avctx->coded_height || avctx->width || avctx->height)
        && (  av_image_check_size(avctx->coded_width, avctx->coded_height, 0, avctx) < 0
           || av_image_check_size(avctx->width,       avctx->height,       0, avctx) < 0)) {
        av_log(avctx, AV_LOG_WARNING, "ignoring invalid width/height values\n");
        avcodec_set_dimensions(avctx, 0, 0);
    }

    /* if the decoder init function was already called previously,
     * free the already allocated subtitle_header before overwriting it */
    if (av_codec_is_decoder(codec))
        av_freep(&avctx->subtitle_header);

    if (avctx->channels > FF_SANE_NB_CHANNELS) {
        ret = AVERROR(EINVAL);
        goto free_and_end;
    }

    avctx->codec = codec;
    if ((avctx->codec_type == AVMEDIA_TYPE_UNKNOWN || avctx->codec_type == codec->type) &&
        avctx->codec_id == AV_CODEC_ID_NONE) {
        avctx->codec_type = codec->type;
        avctx->codec_id   = codec->id;
    }
    if (avctx->codec_id != codec->id || (avctx->codec_type != codec->type
                                         && avctx->codec_type != AVMEDIA_TYPE_ATTACHMENT)) {
        av_log(avctx, AV_LOG_ERROR, "codec type or id mismatches\n");
        ret = AVERROR(EINVAL);
        goto free_and_end;
    }
    avctx->frame_number = 0;

    if (avctx->codec->capabilities & CODEC_CAP_EXPERIMENTAL &&
        avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
        ret = AVERROR_EXPERIMENTAL;
        goto free_and_end;
    }

    if (avctx->codec_type == AVMEDIA_TYPE_AUDIO &&
        (!avctx->time_base.num || !avctx->time_base.den)) {
        avctx->time_base.num = 1;
        avctx->time_base.den = avctx->sample_rate;
    }

    if (HAVE_THREADS && !avctx->thread_opaque) {
        ret = ff_thread_init(avctx);
        if (ret < 0) {
            goto free_and_end;
        }
    }
    if (!HAVE_THREADS && !(codec->capabilities & CODEC_CAP_AUTO_THREADS))
        avctx->thread_count = 1;

    if (av_codec_is_encoder(avctx->codec)) {
        int i;
        if (avctx->codec->sample_fmts) {
            for (i = 0; avctx->codec->sample_fmts[i] != AV_SAMPLE_FMT_NONE; i++) {
                if (avctx->sample_fmt == avctx->codec->sample_fmts[i])
                    break;
                if (avctx->channels == 1 &&
                    av_get_planar_sample_fmt(avctx->sample_fmt) ==
                    av_get_planar_sample_fmt(avctx->codec->sample_fmts[i])) {
                    avctx->sample_fmt = avctx->codec->sample_fmts[i];
                    break;
                }
            }
            if (avctx->codec->sample_fmts[i] == AV_SAMPLE_FMT_NONE) {
                av_log(avctx, AV_LOG_ERROR, "Specified sample_fmt is not supported.\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->pix_fmts) {
            for (i = 0; avctx->codec->pix_fmts[i] != AV_PIX_FMT_NONE; i++)
                if (avctx->pix_fmt == avctx->codec->pix_fmts[i])
                    break;
            if (avctx->codec->pix_fmts[i] == AV_PIX_FMT_NONE) {
                av_log(avctx, AV_LOG_ERROR, "Specified pix_fmt is not supported\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->supported_samplerates) {
            for (i = 0; avctx->codec->supported_samplerates[i] != 0; i++)
                if (avctx->sample_rate == avctx->codec->supported_samplerates[i])
                    break;
            if (avctx->codec->supported_samplerates[i] == 0) {
                av_log(avctx, AV_LOG_ERROR, "Specified sample_rate is not supported\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->channel_layouts) {
            if (!avctx->channel_layout) {
                av_log(avctx, AV_LOG_WARNING, "channel_layout not specified\n");
            } else {
                for (i = 0; avctx->codec->channel_layouts[i] != 0; i++)
                    if (avctx->channel_layout == avctx->codec->channel_layouts[i])
                        break;
                if (avctx->codec->channel_layouts[i] == 0) {
                    av_log(avctx, AV_LOG_ERROR, "Specified channel_layout is not supported\n");
                    ret = AVERROR(EINVAL);
                    goto free_and_end;
                }
            }
        }
        if (avctx->channel_layout && avctx->channels) {
            if (av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels) {
                av_log(avctx, AV_LOG_ERROR, "channel layout does not match number of channels\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        } else if (avctx->channel_layout) {
            avctx->channels = av_get_channel_layout_nb_channels(avctx->channel_layout);
        }

        if (!avctx->rc_initial_buffer_occupancy)
            avctx->rc_initial_buffer_occupancy = avctx->rc_buffer_size * 3 / 4;
    }

    if (avctx->codec->init && !(avctx->active_thread_type & FF_THREAD_FRAME)) {
        ret = avctx->codec->init(avctx);
        if (ret < 0) {