static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { PNGDecContext *const s = avctx->priv_data; const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; AVFrame *p = data; uint8_t *crow_buf_base = NULL; uint32_t tag, length; int ret; /* check signature */ if (buf_size < 8 || memcmp(buf, ff_pngsig, 8) != 0 && memcmp(buf, ff_mngsig, 8) != 0) return -1; bytestream2_init(&s->gb, buf + 8, buf_size - 8); s->y = s->state = 0; /* init the zlib */ s->zstream.zalloc = ff_png_zalloc; s->zstream.zfree = ff_png_zfree; s->zstream.opaque = NULL; ret = inflateInit(&s->zstream); if (ret != Z_OK) return -1; for (;;) { if (bytestream2_get_bytes_left(&s->gb) <= 0) goto fail; length = bytestream2_get_be32(&s->gb); if (length > 0x7fffffff) goto fail; tag = bytestream2_get_le32(&s->gb); av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n", (tag & 0xff), ((tag >> 8) & 0xff), ((tag >> 16) & 0xff), ((tag >> 24) & 0xff), length); switch (tag) { case MKTAG('I', 'H', 'D', 'R'): if (length != 13) goto fail; s->width = bytestream2_get_be32(&s->gb); s->height = bytestream2_get_be32(&s->gb); if (av_image_check_size(s->width, s->height, 0, avctx)) { s->width = s->height = 0; goto fail; } s->bit_depth = bytestream2_get_byte(&s->gb); s->color_type = bytestream2_get_byte(&s->gb); s->compression_type = bytestream2_get_byte(&s->gb); s->filter_type = bytestream2_get_byte(&s->gb); s->interlace_type = bytestream2_get_byte(&s->gb); bytestream2_skip(&s->gb, 4); /* crc */ s->state |= PNG_IHDR; av_dlog(avctx, "width=%d height=%d depth=%d color_type=%d " "compression_type=%d filter_type=%d interlace_type=%d\n", s->width, s->height, s->bit_depth, s->color_type, s->compression_type, s->filter_type, s->interlace_type); break; case MKTAG('I', 'D', 'A', 'T'): if (!(s->state & PNG_IHDR)) goto fail; if (!(s->state & PNG_IDAT)) { /* init image info */ avctx->width = s->width; avctx->height = s->height; s->channels = ff_png_get_nb_channels(s->color_type); s->bits_per_pixel = s->bit_depth * s->channels; s->bpp = (s->bits_per_pixel + 7) >> 3; s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3; if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_RGB) { avctx->pix_fmt = AV_PIX_FMT_RGB24; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_RGB32; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_GRAY8; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_GRAY16BE; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_RGB) { avctx->pix_fmt = AV_PIX_FMT_RGB48BE; } else if (s->bit_depth == 1 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_MONOBLACK; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_PALETTE) { avctx->pix_fmt = AV_PIX_FMT_PAL8; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_YA8; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_YA16BE; } else { goto fail; } if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); goto fail; } p->pict_type = AV_PICTURE_TYPE_I; p->key_frame = 1; p->interlaced_frame = !!s->interlace_type; /* compute the compressed row size */ if (!s->interlace_type) { s->crow_size = s->row_size + 1; } else { s->pass = 0; s->pass_row_size = ff_png_pass_row_size(s->pass, s->bits_per_pixel, s->width); s->crow_size = s->pass_row_size + 1; } av_dlog(avctx, "row_size=%d crow_size =%d\n", s->row_size, s->crow_size); s->image_buf = p->data[0]; s->image_linesize = p->linesize[0]; /* copy the palette if needed */ if (s->color_type == PNG_COLOR_TYPE_PALETTE) memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t)); /* empty row is used if differencing to the first row */ s->last_row = av_mallocz(s->row_size); if (!s->last_row) goto fail; if (s->interlace_type || s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { s->tmp_row = av_malloc(s->row_size); if (!s->tmp_row) goto fail; } /* compressed row */ crow_buf_base = av_malloc(s->row_size + 16); if (!crow_buf_base) goto fail; /* we want crow_buf+1 to be 16-byte aligned */ s->crow_buf = crow_buf_base + 15; s->zstream.avail_out = s->crow_size; s->zstream.next_out = s->crow_buf; } s->state |= PNG_IDAT; if (png_decode_idat(s, length) < 0) goto fail; bytestream2_skip(&s->gb, 4); /* crc */ break; case MKTAG('P', 'L', 'T', 'E'): { int n, i, r, g, b; if ((length % 3) != 0 || length > 256 * 3) goto skip_tag; /* read the palette */ n = length / 3; for (i = 0; i < n; i++) { r = bytestream2_get_byte(&s->gb); g = bytestream2_get_byte(&s->gb); b = bytestream2_get_byte(&s->gb); s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b; } for (; i < 256; i++) s->palette[i] = (0xff << 24); s->state |= PNG_PLTE; bytestream2_skip(&s->gb, 4); /* crc */ } break; case MKTAG('t', 'R', 'N', 'S'): { int v, i; /* read the transparency. XXX: Only palette mode supported */ if (s->color_type != PNG_COLOR_TYPE_PALETTE || length > 256 || !(s->state & PNG_PLTE)) goto skip_tag; for (i = 0; i < length; i++) { v = bytestream2_get_byte(&s->gb); s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); } bytestream2_skip(&s->gb, 4); /* crc */ } break; case MKTAG('I', 'E', 'N', 'D'): if (!(s->state & PNG_ALLIMAGE)) goto fail; bytestream2_skip(&s->gb, 4); /* crc */ goto exit_loop; default: /* skip tag */ skip_tag: bytestream2_skip(&s->gb, length + 4); break; } } exit_loop: /* handle p-frames only if a predecessor frame is available */ if (s->prev->data[0]) { if (!(avpkt->flags & AV_PKT_FLAG_KEY)) { int i, j; uint8_t *pd = p->data[0]; uint8_t *pd_last = s->prev->data[0]; for (j = 0; j < s->height; j++) { for (i = 0; i < s->width * s->bpp; i++) pd[i] += pd_last[i]; pd += s->image_linesize; pd_last += s->image_linesize; } } } av_frame_unref(s->prev); if ((ret = av_frame_ref(s->prev, p)) < 0) goto fail; *got_frame = 1; ret = bytestream2_tell(&s->gb); the_end: inflateEnd(&s->zstream); av_free(crow_buf_base); s->crow_buf = NULL; av_freep(&s->last_row); av_freep(&s->tmp_row); return ret; fail: ret = -1; goto the_end; }