Function av_exif_write

libavcodec/exif.c:752–879

}

int av_exif_write(void *logctx, const AVExifMetadata *ifd, AVBufferRef **buffer, enum AVExifHeaderMode header_mode)
{
    AVBufferRef *buf = NULL;
    size_t size, headsize = 8;
    PutByteContext pb;
    int ret = 0, off = 0, next;
    AVExifMetadata *ifd_new = NULL;
    AVExifMetadata extra_ifds[16] = { 0 };

    int le = 1;

    if (*buffer) {
        ret = AVERROR(EINVAL);
        goto end;
    }

    size = exif_get_ifd_size(ifd);
    switch (header_mode) {
        case AV_EXIF_EXIF00:
            off = 6;
            break;
        case AV_EXIF_T_OFF:
            off = 4;
            break;
        case AV_EXIF_ASSUME_BE:
            le = 0;
            headsize = 0;
            break;
        case AV_EXIF_ASSUME_LE:
            le = 1;
            headsize = 0;
            break;
    }

    ret = av_buffer_realloc(&buf, size + off + headsize);
    if (ret < 0)
        goto end;

    if (header_mode == AV_EXIF_EXIF00) {
        AV_WL32(buf->data, MKTAG('E','x','i','f'));
        AV_WN16(buf->data + 4, 0);
    } else if (header_mode == AV_EXIF_T_OFF) {
        AV_WN32(buf->data, 0);
    }

    bytestream2_init_writer(&pb, buf->data + off, buf->size - off);

    if (header_mode != AV_EXIF_ASSUME_BE && header_mode != AV_EXIF_ASSUME_LE) {
        /* these constants are be32 in both cases */
        /* le == 1 always in this case */
        bytestream2_put_be32(&pb, EXIF_II_LONG);
        tput32(&pb, le, 8);
    }

    int extras = 0;
    for (int i = 0; i < FF_ARRAY_ELEMS(extra_ifds); i++) {
        AVExifEntry *extra_entry = NULL;
        uint16_t extra_tag = 0xFFFCu - i;