yading@10: /*
yading@10:  * Flash Screen Video encoder
yading@10:  * Copyright (C) 2004 Alex Beregszaszi
yading@10:  * Copyright (C) 2006 Benjamin Larsson
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /* Encoding development sponsored by http://fh-campuswien.ac.at */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Flash Screen Video encoder
yading@10:  * @author Alex Beregszaszi
yading@10:  * @author Benjamin Larsson
yading@10:  *
yading@10:  * A description of the bitstream format for Flash Screen Video version 1/2
yading@10:  * is part of the SWF File Format Specification (version 10), which can be
yading@10:  * downloaded from http://www.adobe.com/devnet/swf.html.
yading@10:  */
yading@10: 
yading@10: /*
yading@10:  * Encoding ideas: A basic encoder would just use a fixed block size.
yading@10:  * Block sizes can be multiples of 16, from 16 to 256. The blocks don't
yading@10:  * have to be quadratic. A brute force search with a set of different
yading@10:  * block sizes should give a better result than to just use a fixed size.
yading@10:  *
yading@10:  * TODO:
yading@10:  * Don't reencode the frame in brute force mode if the frame is a dupe.
yading@10:  * Speed up. Make the difference check faster.
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <stdlib.h>
yading@10: #include <zlib.h>
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "put_bits.h"
yading@10: #include "bytestream.h"
yading@10: 
yading@10: 
yading@10: typedef struct FlashSVContext {
yading@10:     AVCodecContext *avctx;
yading@10:     uint8_t        *previous_frame;
yading@10:     AVFrame         frame;
yading@10:     int             image_width, image_height;
yading@10:     int             block_width, block_height;
yading@10:     uint8_t        *tmpblock;
yading@10:     uint8_t        *encbuffer;
yading@10:     int             block_size;
yading@10:     z_stream        zstream;
yading@10:     int             last_key_frame;
yading@10: } FlashSVContext;
yading@10: 
yading@10: static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, int dx, int dy,
yading@10:                            int h, int w, int stride, uint8_t *pfptr)
yading@10: {
yading@10:     int i, j;
yading@10:     uint8_t *nsptr;
yading@10:     uint8_t *npfptr;
yading@10:     int diff = 0;
yading@10: 
yading@10:     for (i = dx + h; i > dx; i--) {
yading@10:         nsptr  = sptr  + i * stride + dy * 3;
yading@10:         npfptr = pfptr + i * stride + dy * 3;
yading@10:         for (j = 0; j < w * 3; j++) {
yading@10:             diff    |= npfptr[j] ^ nsptr[j];
yading@10:             dptr[j]  = nsptr[j];
yading@10:         }
yading@10:         dptr += w * 3;
yading@10:     }
yading@10:     if (diff)
yading@10:         return 1;
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int flashsv_encode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     FlashSVContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10: 
yading@10:     if (avctx->width > 4095 || avctx->height > 4095) {
yading@10:         av_log(avctx, AV_LOG_ERROR,
yading@10:                "Input dimensions too large, input must be max 4096x4096 !\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     // Needed if zlib unused or init aborted before deflateInit
yading@10:     memset(&s->zstream, 0, sizeof(z_stream));
yading@10: 
yading@10:     s->last_key_frame = 0;
yading@10: 
yading@10:     s->image_width  = avctx->width;
yading@10:     s->image_height = avctx->height;
yading@10: 
yading@10:     s->tmpblock  = av_mallocz(3 * 256 * 256);
yading@10:     s->encbuffer = av_mallocz(s->image_width * s->image_height * 3);
yading@10: 
yading@10:     if (!s->tmpblock || !s->encbuffer) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf,
yading@10:                             int buf_size, int block_width, int block_height,
yading@10:                             uint8_t *previous_frame, int *I_frame)
yading@10: {
yading@10: 
yading@10:     PutBitContext pb;
yading@10:     int h_blocks, v_blocks, h_part, v_part, i, j;
yading@10:     int buf_pos, res;
yading@10:     int pred_blocks = 0;
yading@10: 
yading@10:     init_put_bits(&pb, buf, buf_size * 8);
yading@10: 
yading@10:     put_bits(&pb,  4, block_width / 16 - 1);
yading@10:     put_bits(&pb, 12, s->image_width);
yading@10:     put_bits(&pb,  4, block_height / 16 - 1);
yading@10:     put_bits(&pb, 12, s->image_height);
yading@10:     flush_put_bits(&pb);
yading@10:     buf_pos = 4;
yading@10: 
yading@10:     h_blocks = s->image_width  / block_width;
yading@10:     h_part   = s->image_width  % block_width;
yading@10:     v_blocks = s->image_height / block_height;
yading@10:     v_part   = s->image_height % block_height;
yading@10: 
yading@10:     /* loop over all block columns */
yading@10:     for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
yading@10: 
yading@10:         int y_pos = j * block_height; // vertical position in frame
yading@10:         int cur_blk_height = (j < v_blocks) ? block_height : v_part;
yading@10: 
yading@10:         /* loop over all block rows */
yading@10:         for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) {
yading@10:             int x_pos = i * block_width; // horizontal position in frame
yading@10:             int cur_blk_width = (i < h_blocks) ? block_width : h_part;
yading@10:             int ret = Z_OK;
yading@10:             uint8_t *ptr = buf + buf_pos;
yading@10: 
yading@10:             /* copy the block to the temp buffer before compression
yading@10:              * (if it differs from the previous frame's block) */
yading@10:             res = copy_region_enc(p->data[0], s->tmpblock,
yading@10:                                   s->image_height - (y_pos + cur_blk_height + 1),
yading@10:                                   x_pos, cur_blk_height, cur_blk_width,
yading@10:                                   p->linesize[0], previous_frame);
yading@10: 
yading@10:             if (res || *I_frame) {
yading@10:                 unsigned long zsize = 3 * block_width * block_height;
yading@10:                 ret = compress2(ptr + 2, &zsize, s->tmpblock,
yading@10:                                 3 * cur_blk_width * cur_blk_height, 9);
yading@10: 
yading@10:                 //ret = deflateReset(&s->zstream);
yading@10:                 if (ret != Z_OK)
yading@10:                     av_log(s->avctx, AV_LOG_ERROR,
yading@10:                            "error while compressing block %dx%d\n", i, j);
yading@10: 
yading@10:                 bytestream_put_be16(&ptr, zsize);
yading@10:                 buf_pos += zsize + 2;
yading@10:                 av_dlog(s->avctx, "buf_pos = %d\n", buf_pos);
yading@10:             } else {
yading@10:                 pred_blocks++;
yading@10:                 bytestream_put_be16(&ptr, 0);
yading@10:                 buf_pos += 2;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if (pred_blocks)
yading@10:         *I_frame = 0;
yading@10:     else
yading@10:         *I_frame = 1;
yading@10: 
yading@10:     return buf_pos;
yading@10: }
yading@10: 
yading@10: 
yading@10: static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
yading@10:                                 const AVFrame *pict, int *got_packet)
yading@10: {
yading@10:     FlashSVContext * const s = avctx->priv_data;
yading@10:     AVFrame * const p = &s->frame;
yading@10:     uint8_t *pfptr;
yading@10:     int res;
yading@10:     int I_frame = 0;
yading@10:     int opt_w = 4, opt_h = 4;
yading@10: 
yading@10:     *p = *pict;
yading@10: 
yading@10:     /* First frame needs to be a keyframe */
yading@10:     if (avctx->frame_number == 0) {
yading@10:         s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height);
yading@10:         if (!s->previous_frame) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
yading@10:             return AVERROR(ENOMEM);
yading@10:         }
yading@10:         I_frame = 1;
yading@10:     }
yading@10: 
yading@10:     if (p->linesize[0] < 0)
yading@10:         pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0];
yading@10:     else
yading@10:         pfptr = s->previous_frame;
yading@10: 
yading@10:     /* Check the placement of keyframes */
yading@10:     if (avctx->gop_size > 0 &&
yading@10:         avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
yading@10:         I_frame = 1;
yading@10:     }
yading@10: 
yading@10:     if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3)) < 0)
yading@10:         return res;
yading@10: 
yading@10:     pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16,
yading@10:                                  pfptr, &I_frame);
yading@10: 
yading@10:     //save the current frame
yading@10:     if (p->linesize[0] > 0)
yading@10:         memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]);
yading@10:     else
yading@10:         memcpy(s->previous_frame,
yading@10:                p->data[0] + p->linesize[0] * (s->image_height - 1),
yading@10:                s->image_height * FFABS(p->linesize[0]));
yading@10: 
yading@10:     //mark the frame type so the muxer can mux it correctly
yading@10:     if (I_frame) {
yading@10:         p->pict_type      = AV_PICTURE_TYPE_I;
yading@10:         p->key_frame      = 1;
yading@10:         s->last_key_frame = avctx->frame_number;
yading@10:         av_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number);
yading@10:     } else {
yading@10:         p->pict_type = AV_PICTURE_TYPE_P;
yading@10:         p->key_frame = 0;
yading@10:     }
yading@10: 
yading@10:     avctx->coded_frame = p;
yading@10: 
yading@10:     if (p->key_frame)
yading@10:         pkt->flags |= AV_PKT_FLAG_KEY;
yading@10:     *got_packet = 1;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int flashsv_encode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     FlashSVContext *s = avctx->priv_data;
yading@10: 
yading@10:     deflateEnd(&s->zstream);
yading@10: 
yading@10:     av_free(s->encbuffer);
yading@10:     av_free(s->previous_frame);
yading@10:     av_free(s->tmpblock);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_flashsv_encoder = {
yading@10:     .name           = "flashsv",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_FLASHSV,
yading@10:     .priv_data_size = sizeof(FlashSVContext),
yading@10:     .init           = flashsv_encode_init,
yading@10:     .encode2        = flashsv_encode_frame,
yading@10:     .close          = flashsv_encode_end,
yading@10:     .pix_fmts       = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE },
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Flash Screen Video"),
yading@10: };