From 3a5b857d4c455f20d811cad81c7251af2f82fba2 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Sun, 14 Feb 2021 15:50:10 +0100 Subject: lavc: split LSCR decoder out of PNG decoder It shares very little code with pngdec, so keeping them together only makes the code harder to read. --- libavcodec/lscrdec.c | 279 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 279 insertions(+) create mode 100644 libavcodec/lscrdec.c (limited to 'libavcodec/lscrdec.c') diff --git a/libavcodec/lscrdec.c b/libavcodec/lscrdec.c new file mode 100644 index 0000000000..5ad0431534 --- /dev/null +++ b/libavcodec/lscrdec.c @@ -0,0 +1,279 @@ +/* + * 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 + */ + +#include +#include + +#include "libavutil/frame.h" +#include "libavutil/error.h" +#include "libavutil/log.h" + +#include "avcodec.h" +#include "bytestream.h" +#include "codec.h" +#include "internal.h" +#include "packet.h" +#include "png.h" +#include "pngdsp.h" + +typedef struct LSCRContext { + PNGDSPContext dsp; + AVCodecContext *avctx; + + AVFrame *last_picture; + uint8_t *buffer; + int buffer_size; + uint8_t *crow_buf; + int crow_size; + uint8_t *last_row; + unsigned int last_row_size; + + GetByteContext gb; + uint8_t *image_buf; + int image_linesize; + int row_size; + int cur_h; + int y; + + z_stream zstream; +} LSCRContext; + +static void handle_row(LSCRContext *s) +{ + uint8_t *ptr, *last_row; + + ptr = s->image_buf + s->image_linesize * s->y; + if (s->y == 0) + last_row = s->last_row; + else + last_row = ptr - s->image_linesize; + + ff_png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1, + last_row, s->row_size, 3); + + s->y++; +} + +static int decode_idat(LSCRContext *s, int length) +{ + int ret; + s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb)); + s->zstream.next_in = s->gb.buffer; + bytestream2_skip(&s->gb, length); + + /* decode one line if possible */ + while (s->zstream.avail_in > 0) { + ret = inflate(&s->zstream, Z_PARTIAL_FLUSH); + if (ret != Z_OK && ret != Z_STREAM_END) { + av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret); + return AVERROR_EXTERNAL; + } + if (s->zstream.avail_out == 0) { + if (s->y < s->cur_h) { + handle_row(s); + } + s->zstream.avail_out = s->crow_size; + s->zstream.next_out = s->crow_buf; + } + if (ret == Z_STREAM_END && s->zstream.avail_in > 0) { + av_log(s->avctx, AV_LOG_WARNING, + "%d undecompressed bytes left in buffer\n", s->zstream.avail_in); + return 0; + } + } + return 0; +} + +static int decode_frame_lscr(AVCodecContext *avctx, + void *data, int *got_frame, + AVPacket *avpkt) +{ + LSCRContext *const s = avctx->priv_data; + GetByteContext *gb = &s->gb; + AVFrame *frame = data; + int ret, nb_blocks, offset = 0; + + if (avpkt->size < 2) + return AVERROR_INVALIDDATA; + if (avpkt->size == 2) + return 0; + + bytestream2_init(gb, avpkt->data, avpkt->size); + + if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) + return ret; + + nb_blocks = bytestream2_get_le16(gb); + if (bytestream2_get_bytes_left(gb) < 2 + nb_blocks * (12 + 8)) + return AVERROR_INVALIDDATA; + + if (s->last_picture->data[0]) { + ret = av_frame_copy(frame, s->last_picture); + if (ret < 0) + return ret; + } + + for (int b = 0; b < nb_blocks; b++) { + int x, y, x2, y2, w, h, left; + uint32_t csize, size; + + s->zstream.zalloc = ff_png_zalloc; + s->zstream.zfree = ff_png_zfree; + s->zstream.opaque = NULL; + + if ((ret = inflateInit(&s->zstream)) != Z_OK) { + av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret); + ret = AVERROR_EXTERNAL; + goto end; + } + + bytestream2_seek(gb, 2 + b * 12, SEEK_SET); + + x = bytestream2_get_le16(gb); + y = bytestream2_get_le16(gb); + x2 = bytestream2_get_le16(gb); + y2 = bytestream2_get_le16(gb); + w = x2-x; + s->cur_h = h = y2-y; + + if (w <= 0 || x < 0 || x >= avctx->width || w + x > avctx->width || + h <= 0 || y < 0 || y >= avctx->height || h + y > avctx->height) { + ret = AVERROR_INVALIDDATA; + goto end; + } + + size = bytestream2_get_le32(gb); + + frame->key_frame = (nb_blocks == 1) && + (w == avctx->width) && + (h == avctx->height) && + (x == 0) && (y == 0); + + bytestream2_seek(gb, 2 + nb_blocks * 12 + offset, SEEK_SET); + csize = bytestream2_get_be32(gb); + if (bytestream2_get_le32(gb) != MKTAG('I', 'D', 'A', 'T')) { + ret = AVERROR_INVALIDDATA; + goto end; + } + + offset += size; + left = size; + + s->y = 0; + s->row_size = w * 3; + + av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16); + if (!s->buffer) { + ret = AVERROR(ENOMEM); + goto end; + } + + av_fast_padded_malloc(&s->last_row, &s->last_row_size, s->row_size); + if (!s->last_row) { + ret = AVERROR(ENOMEM); + goto end; + } + + s->crow_size = w * 3 + 1; + s->crow_buf = s->buffer + 15; + s->zstream.avail_out = s->crow_size; + s->zstream.next_out = s->crow_buf; + s->image_buf = frame->data[0] + (avctx->height - y - 1) * frame->linesize[0] + x * 3; + s->image_linesize =-frame->linesize[0]; + + while (left > 16) { + ret = decode_idat(s, csize); + if (ret < 0) + goto end; + left -= csize + 16; + if (left > 16) { + bytestream2_skip(gb, 4); + csize = bytestream2_get_be32(gb); + if (bytestream2_get_le32(gb) != MKTAG('I', 'D', 'A', 'T')) { + ret = AVERROR_INVALIDDATA; + goto end; + } + } + } + + inflateEnd(&s->zstream); + } + + frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P; + + av_frame_unref(s->last_picture); + if ((ret = av_frame_ref(s->last_picture, frame)) < 0) + return ret; + + *got_frame = 1; +end: + inflateEnd(&s->zstream); + + if (ret < 0) + return ret; + return avpkt->size; +} + +static int lscr_decode_close(AVCodecContext *avctx) +{ + LSCRContext *s = avctx->priv_data; + + av_frame_free(&s->last_picture); + av_freep(&s->buffer); + av_freep(&s->last_row); + + return 0; +} + +static int lscr_decode_init(AVCodecContext *avctx) +{ + LSCRContext *s = avctx->priv_data; + + avctx->color_range = AVCOL_RANGE_JPEG; + avctx->pix_fmt = AV_PIX_FMT_BGR24; + + s->avctx = avctx; + s->last_picture = av_frame_alloc(); + if (!s->last_picture) + return AVERROR(ENOMEM); + + ff_pngdsp_init(&s->dsp); + + return 0; +} + +static void lscr_decode_flush(AVCodecContext *avctx) +{ + LSCRContext *s = avctx->priv_data; + av_frame_unref(s->last_picture); +} + +AVCodec ff_lscr_decoder = { + .name = "lscr", + .long_name = NULL_IF_CONFIG_SMALL("LEAD Screen Capture"), + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_LSCR, + .priv_data_size = sizeof(LSCRContext), + .init = lscr_decode_init, + .close = lscr_decode_close, + .decode = decode_frame_lscr, + .flush = lscr_decode_flush, + .capabilities = AV_CODEC_CAP_DR1, + .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_THREADSAFE | + FF_CODEC_CAP_ALLOCATE_PROGRESS, +}; -- cgit v1.2.3