libavcodec/flashsvenc.c - third_party/ffmpeg - Git at Google

 /*
  * 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 },
 };
	/*
	* 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 },
	};