| /* | |
| * Flash Screen Video encoder | |
| * Copyright (C) 2004 Alex Beregszaszi | |
| * Copyright (C) 2006 Benjamin Larsson | |
| * | |
| * 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 | |
| */ | |
| /* Encoding development sponsored by http://fh-campuswien.ac.at */ | |
| /** | |
| * @file | |
| * Flash Screen Video encoder | |
| * @author Alex Beregszaszi | |
| * @author Benjamin Larsson | |
| * | |
| * A description of the bitstream format for Flash Screen Video version 1/2 | |
| * is part of the SWF File Format Specification (version 10), which can be | |
| * downloaded from http://www.adobe.com/devnet/swf.html. | |
| */ | |
| /* | |
| * Encoding ideas: A basic encoder would just use a fixed block size. | |
| * Block sizes can be multiples of 16, from 16 to 256. The blocks don't | |
| * have to be quadratic. A brute force search with a set of different | |
| * block sizes should give a better result than to just use a fixed size. | |
| * | |
| * TODO: | |
| * Don't reencode the frame in brute force mode if the frame is a dupe. | |
| * Speed up. Make the difference check faster. | |
| */ | |
| #include <stdint.h> | |
| #include <zlib.h> | |
| #include "libavutil/buffer.h" | |
| #include "avcodec.h" | |
| #include "codec_internal.h" | |
| #include "encode.h" | |
| #include "put_bits.h" | |
| #include "bytestream.h" | |
| /* These values are hardcoded for now. */ | |
| #define BLOCK_WIDTH (4 * 16U) | |
| #define BLOCK_HEIGHT (4 * 16U) | |
| typedef struct FlashSVContext { | |
| AVCodecContext *avctx; | |
| const uint8_t *previous_frame; | |
| AVBufferRef *prev_frame_buf; | |
| int image_width, image_height; | |
| unsigned packet_size; | |
| int64_t last_key_frame; | |
| uint8_t tmpblock[3 * 256 * 256]; | |
| } FlashSVContext; | |
| static int copy_region_enc(const uint8_t *sptr, uint8_t *dptr, int dx, int dy, | |
| int h, int w, int stride, const uint8_t *pfptr) | |
| { | |
| int i, j; | |
| int diff = 0; | |
| for (i = dx + h; i > dx; i--) { | |
| const uint8_t *nsptr = sptr + i * stride + dy * 3; | |
| const uint8_t *npfptr = pfptr + i * stride + dy * 3; | |
| for (j = 0; j < w * 3; j++) { | |
| diff |= npfptr[j] ^ nsptr[j]; | |
| dptr[j] = nsptr[j]; | |
| } | |
| dptr += w * 3; | |
| } | |
| if (diff) | |
| return 1; | |
| return 0; | |
| } | |
| static av_cold int flashsv_encode_end(AVCodecContext *avctx) | |
| { | |
| FlashSVContext *s = avctx->priv_data; | |
| av_buffer_unref(&s->prev_frame_buf); | |
| return 0; | |
| } | |
| static av_cold int flashsv_encode_init(AVCodecContext *avctx) | |
| { | |
| FlashSVContext *s = avctx->priv_data; | |
| int h_blocks, v_blocks, nb_blocks; | |
| s->avctx = avctx; | |
| if (avctx->width > 4095 || avctx->height > 4095) { | |
| av_log(avctx, AV_LOG_ERROR, | |
| "Input dimensions too large, input must be max 4095x4095 !\n"); | |
| return AVERROR_INVALIDDATA; | |
| } | |
| s->last_key_frame = 0; | |
| s->image_width = avctx->width; | |
| s->image_height = avctx->height; | |
| h_blocks = (s->image_width + BLOCK_WIDTH - 1) / BLOCK_WIDTH; | |
| v_blocks = (s->image_height + BLOCK_WIDTH - 1) / BLOCK_WIDTH; | |
| nb_blocks = h_blocks * v_blocks; | |
| s->packet_size = 4 + nb_blocks * (2 + 3 * BLOCK_WIDTH * BLOCK_HEIGHT); | |
| return 0; | |
| } | |
| static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf, | |
| int buf_size, int block_width, int block_height, | |
| const uint8_t *previous_frame, int *I_frame) | |
| { | |
| PutBitContext pb; | |
| int h_blocks, v_blocks, h_part, v_part, i, j; | |
| int buf_pos, res; | |
| int pred_blocks = 0; | |
| init_put_bits(&pb, buf, buf_size); | |
| put_bits(&pb, 4, block_width / 16 - 1); | |
| put_bits(&pb, 12, s->image_width); | |
| put_bits(&pb, 4, block_height / 16 - 1); | |
| put_bits(&pb, 12, s->image_height); | |
| flush_put_bits(&pb); | |
| buf_pos = 4; | |
| h_blocks = s->image_width / block_width; | |
| h_part = s->image_width % block_width; | |
| v_blocks = s->image_height / block_height; | |
| v_part = s->image_height % block_height; | |
| /* loop over all block columns */ | |
| for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { | |
| int y_pos = j * block_height; // vertical position in frame | |
| int cur_blk_height = (j < v_blocks) ? block_height : v_part; | |
| /* loop over all block rows */ | |
| for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { | |
| int x_pos = i * block_width; // horizontal position in frame | |
| int cur_blk_width = (i < h_blocks) ? block_width : h_part; | |
| int ret = Z_OK; | |
| uint8_t *ptr = buf + buf_pos; | |
| /* copy the block to the temp buffer before compression | |
| * (if it differs from the previous frame's block) */ | |
| res = copy_region_enc(p->data[0], s->tmpblock, | |
| s->image_height - (y_pos + cur_blk_height + 1), | |
| x_pos, cur_blk_height, cur_blk_width, | |
| p->linesize[0], previous_frame); | |
| if (res || *I_frame) { | |
| unsigned long zsize = 3 * block_width * block_height; | |
| ret = compress2(ptr + 2, &zsize, s->tmpblock, | |
| 3 * cur_blk_width * cur_blk_height, 9); | |
| if (ret != Z_OK) | |
| av_log(s->avctx, AV_LOG_ERROR, | |
| "error while compressing block %dx%d\n", i, j); | |
| bytestream_put_be16(&ptr, zsize); | |
| buf_pos += zsize + 2; | |
| ff_dlog(s->avctx, "buf_pos = %d\n", buf_pos); | |
| } else { | |
| pred_blocks++; | |
| bytestream_put_be16(&ptr, 0); | |
| buf_pos += 2; | |
| } | |
| } | |
| } | |
| if (pred_blocks) | |
| *I_frame = 0; | |
| else | |
| *I_frame = 1; | |
| return buf_pos; | |
| } | |
| static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt, | |
| const AVFrame *pict, int *got_packet) | |
| { | |
| FlashSVContext * const s = avctx->priv_data; | |
| const uint8_t *prev_frame = s->previous_frame; | |
| int res; | |
| int I_frame = 0; | |
| int opt_w = 4, opt_h = 4; | |
| /* First frame needs to be a keyframe */ | |
| if (!s->previous_frame) { | |
| prev_frame = pict->data[0]; | |
| I_frame = 1; | |
| } | |
| /* Check the placement of keyframes */ | |
| if (avctx->gop_size > 0 && | |
| avctx->frame_num >= s->last_key_frame + avctx->gop_size) { | |
| I_frame = 1; | |
| } | |
| res = ff_alloc_packet(avctx, pkt, s->packet_size); | |
| if (res < 0) | |
| return res; | |
| pkt->size = encode_bitstream(s, pict, pkt->data, pkt->size, | |
| opt_w * 16, opt_h * 16, | |
| prev_frame, &I_frame); | |
| //mark the frame type so the muxer can mux it correctly | |
| if (I_frame) { | |
| s->last_key_frame = avctx->frame_num; | |
| ff_dlog(avctx, "Inserting keyframe at frame %"PRId64"\n", avctx->frame_num); | |
| } | |
| if (I_frame) | |
| pkt->flags |= AV_PKT_FLAG_KEY; | |
| *got_packet = 1; | |
| //save the current frame | |
| res = av_buffer_replace(&s->prev_frame_buf, pict->buf[0]); | |
| if (res < 0) | |
| return res; | |
| s->previous_frame = pict->data[0]; | |
| return 0; | |
| } | |
| const FFCodec ff_flashsv_encoder = { | |
| .p.name = "flashsv", | |
| CODEC_LONG_NAME("Flash Screen Video"), | |
| .p.type = AVMEDIA_TYPE_VIDEO, | |
| .p.id = AV_CODEC_ID_FLASHSV, | |
| .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE, | |
| .priv_data_size = sizeof(FlashSVContext), | |
| .init = flashsv_encode_init, | |
| FF_CODEC_ENCODE_CB(flashsv_encode_frame), | |
| .close = flashsv_encode_end, | |
| .p.pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE }, | |
| }; |