/* * 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 #include #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 }, };