[FFmpeg-devel] [PATCH] encoder for adobe's flash ScreenVideo2

Leon Ou leono
Wed Mar 16 06:53:10 CET 2011


Hi all,

In the mail list, I find a encoder for adobe's flash ScreenVideo2 written by Joshua. After read the code below. I make some changes to this code to decreases  the size of encoded data for the situation of pool bandwidth.
In Joshua code, the low 3 bits of every channel of RGB are discarded.  But in my code, the low 4 bits of every channel of RGB are discarded. After the test, discarding the low 4 bits doesn't lower  the picture quality significantly.
Below is the test data of this two ways:

A Screen capture with 1440*900, the raw data is 3.7MB.

Reserving high 5 bits +Default Palette+ZLIB..................The encode size is 680KB

Reserving high 4 bits +Default Palette+ZLIB..................The encode size is 350KB

After discussion with Joshua, I change one method in his code and add two new methods to compatible the two ways.

1.Change the method: pixel_color15.
static inline unsigned pixel_color15(const uint8_t * src, int mask)
{
return ((src[0] & mask) >> 3) | ((src[1] & mask) << 2) | ((src[2] & mask) << 7);
}

Add a parameter 'mask' to the  pixel_color15

2. Add two new methods.
static int update_palette_index_size(Palette * palette)

{
 for(int i =0; i<32768;i++)
 {
    palette->index[i] = 0x80;
 }

 for (int index = 0; index < 128; index++)
 {
  uint8_t c_r = palette->colors[index]>>16;
  uint8_t c_g = palette->colors[index]>>8 & 0xff;
  uint8_t c_b = palette->colors[index] & 0xff;
  unsigned palette_color_15 = ((c_b & 0xf0) >> 3) | ((c_g & 0xf0) << 2) | ((c_r & 0xf0) << 7);
     unsigned short bgri = (unsigned short)palette_color_15;
     palette->index[bgri] = index;
 }
 return 0;
}

 static int write_pixel_15_7_size(Palette * palette, uint8_t * dest, const uint8_t * src, int dist)
{
 unsigned short c15_4bits = pixel_color15(src, mask);
 if (palette->index[c15_4bits]!=0x80)
 {
  dest[0] = (uint8_t) palette->index[c15_4bits];
  return 1;
 }
 else
 {
  dest[0] = 0x80 | (uint8_t) (c15_4bits >> 8);
  dest[1] = c15_4bits & 0xff;
  return 2;
 }
}

Whiling focus on screen capture image size, the update_palette_index_size and write_pixel_15_7_size will be replace the update_palette_index and write_pixel_15_7 in your code. In the write_pixel_15_7_size, the 'dist' parameter is used as 'mask'. So, in the flashsv2_encode_frame, the dist should be set to 0xF0.

Whiling focus on screen capture image quality, the update_palette_index and write_pixel_15_7 should be chosen and passes the "0xF1" for the 'mask' parameter of method  pixel_color15.








Him



I fixed the issues you guys have commented on (tell me if I

accidentally missed one), and the revised patch is attached.



Joshua Warner



On Wed, Jul 22, 2009 at 10:40 AM, Vitor Sessak<vitor1001 at gmail.com<https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel>> wrote:

> Joshua Warner wrote:

>>

>> On Tue, Jul 21, 2009 at 12:13 PM, Daniel Verkamp<daniel at drv.nu<https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel>> wrote:

>>>

>>> On Tue, Jul 21, 2009 at 10:57 AM, Joshua Warner<joshuawarner32 at gmail.com<https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel>>

>>> wrote:

>>>>

>>>> Hi all,

>>>>

>>>> I've developed an encoder for Adobe's Flash ScreenVideo2 format, which

>>>> is

>>>> stored in flv files.  My encoder currently only supports a large subset

>>>> of

>>>> the format.  The only player that supports this codec (so far) is Adobe

>>>> Flash Player itself, but ScreenVideo2 makes dramatic improvement in file

>>>> size over ScreenVideo (currently in ffmpeg as flashsv) - and should be

>>>> very

>>>> useful for uploading screencasts, etc.  Most options (block size, etc)

>>>> now

>>>> just fall back on defaults because I couldn't find a general algorithm

>>>> that

>>>> produced consistantly better results than these.  All the code is in

>>>> place

>>>> to be able to change these parameters dynamically, so future

>>>> improvements

>>>> there should be easy.  The patch is attached.

>>>>

>>>> The codec is listed as flashsv2 in ffmpeg.

>>>>

>>>> Joshua Warner

>>>

>>> Minor nitpicks:

>>>  - "palette" is misspelled as "pallet" throughout

>>>  - trailing whitespace on 2 lines

>>>  - plenty of warnings from tools/patcheck

>>

>> I ran tools/patcheck (which I wasn't aware of before), and most of the

>> output was either false positives or would reduce readability of the

>> code.

>

> It does gives a few false positives. All the "x==0 / x!=0 can be simplified

> to !x / x" is a matter of preferred style in FFmpeg (the readability depends

> on how used you are to it). The "missing const" are mostly correct.

>

>> I'm not sure what to do about the comments that it complains

>> are not doxygen compliant - they are things that don't have any

>> applicability outside flashsv2enc.c... should I appease patcheck?

>

> We prefer to add doxy comments for things that would improve the doxygen

> documentation of the file. Typically struct members and comments before

> functions describing what it does.

>

> -Vitor

> _______________________________________________

> ffmpeg-devel mailing list

> ffmpeg-devel at mplayerhq.hu<https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel>

> https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel

>

-------------- next part --------------

Index: configure

===================================================================

--- configure                   (revision 19479)

+++ configure                (working copy)

@@ -1065,6 +1065,7 @@

 flac_encoder_select="golomb"

 flashsv_decoder_select="zlib"

 flashsv_encoder_select="zlib"

+flashsv2_encoder_select="zlib"

 flv_encoder_select="aandct"

 h261_encoder_select="aandct"

 h263_encoder_select="aandct"

Index: Changelog

===================================================================

--- Changelog                (revision 19479)

+++ Changelog             (working copy)

@@ -191,6 +191,7 @@

 - Gopher client support

 - MXF D-10 muxer

 - generic metadata API

+- flash ScreenVideo2 encoder







Index: libavcodec/allcodecs.c

===================================================================

--- libavcodec/allcodecs.c               (revision 19479)

+++ libavcodec/allcodecs.c            (working copy)

@@ -92,6 +92,7 @@

     REGISTER_ENCDEC  (FFV1, ffv1);

     REGISTER_ENCDEC  (FFVHUFF, ffvhuff);

     REGISTER_ENCDEC  (FLASHSV, flashsv);

+    REGISTER_ENCODER (FLASHSV2, flashsv2);

     REGISTER_DECODER (FLIC, flic);

     REGISTER_ENCDEC  (FLV, flv);

     REGISTER_DECODER (FOURXM, fourxm);

Index: libavcodec/avcodec.h

===================================================================

--- libavcodec/avcodec.h                (revision 19479)

+++ libavcodec/avcodec.h             (working copy)

@@ -30,7 +30,7 @@

 #include "libavutil/avutil.h"



 #define LIBAVCODEC_VERSION_MAJOR 52

-#define LIBAVCODEC_VERSION_MINOR 32

+#define LIBAVCODEC_VERSION_MINOR 33

 #define LIBAVCODEC_VERSION_MICRO  0



 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \

@@ -198,6 +198,7 @@

     CODEC_ID_V210,

     CODEC_ID_DPX,

     CODEC_ID_MAD,

+    CODEC_ID_FLASHSV2,



     /* various PCM "codecs" */

     CODEC_ID_PCM_S16LE= 0x10000,

Index: libavcodec/Makefile

===================================================================

--- libavcodec/Makefile                   (revision 19479)

+++ libavcodec/Makefile                (working copy)

@@ -92,6 +92,7 @@

 OBJS-$(CONFIG_FLAC_ENCODER)            += flacenc.o flacdata.o flac.o lpc.o

 OBJS-$(CONFIG_FLASHSV_DECODER)         += flashsv.o

 OBJS-$(CONFIG_FLASHSV_ENCODER)         += flashsvenc.o

+OBJS-$(CONFIG_FLASHSV2_ENCODER)        += flashsv2enc.o

 OBJS-$(CONFIG_FLIC_DECODER)            += flicvideo.o

 OBJS-$(CONFIG_FLV_DECODER)             += h263dec.o h263.o mpeg12data.o mpegvideo.o error_resilience.o

 OBJS-$(CONFIG_FLV_ENCODER)             += mpegvideo_enc.o motion_est.o ratecontrol.o h263.o mpeg12data.o mpegvideo.o error_resilience.o

Index: libavcodec/flashsv2enc.c

===================================================================

--- libavcodec/flashsv2enc.c          (revision 0)

+++ libavcodec/flashsv2enc.c       (revision 0)

@@ -0,0 +1,912 @@

+/*

+ * Flash Screen Video Version 2 encoder

+ * Copyright (C) 2009 Joshua Warner

+ *

+ * 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

+ */

+

+/**

+ * @file libavcodec/flashsv2enc.c

+ * Flash Screen Video Version 2 encoder

+ * @author Joshua Warner

+ */

+

+/* Differences from version 1 stream:

+ * NOTE: Currently, the only player that supports version 2 streams is Adobe Flash Player itself.

+ * * Supports sending only a range of scanlines in a block,

+ *   indicating a difference from the corresponding block in the last keyframe.

+ * * Supports initializing the zlib dictionary with data from the corresponding

+ *   block in the last keyframe, to improve compression.

+ * * Supports a hybrid 15-bit rgb / 7-bit palette color space.

+ */

+

+/* TODO:

+ * Don't keep Block structures for both current frame and keyframe.

+ * Make better heuristics for deciding stream parameters (optimum_* functions).  Currently these return constants.

+ * Figure out how to encode palette information in the stream, choose an optimum palette at each keyframe.

+ * Figure out how the zlibPrimeCompressCurrent flag works, implement support.

+ * Find other sample files (that weren't generated here), develop a decoder.

+ */

+

+#include <stdio.h>

+#include <stdlib.h>

+#include <zlib.h>

+

+#include "avcodec.h"

+#include "put_bits.h"

+#include "bytestream.h"

+

+#define HAS_IFRAME_IMAGE 0x02

+#define HAS_PALLET_INFO 0x01

+

+#define COLORSPACE_BGR 0x00

+#define COLORSPACE_15_7 0x10

+#define HAS_DIFF_BLOCKS 0x04

+#define ZLIB_PRIME_COMPRESS_CURRENT 0x02

+#define ZLIB_PRIME_COMPRESS_PREVIOUS 0x01

+

+// Disables experimental "smart" parameter-choosing code, as well as the statistics that it depends on.

+// At the moment, the "smart" code is a great example of how the parameters *shouldn't* be chosen.

+#define FLASHSV2_DUMB

+

+typedef struct Block {

+    uint8_t *enc;

+    uint8_t *sl_begin, *sl_end;

+    int enc_size;

+    uint8_t *data;

+    unsigned long data_size;

+

+    uint8_t start, len;

+    uint8_t dirty;

+    uint8_t col, row, width, height;

+    uint8_t flags;

+} Block;

+

+typedef struct Palette {

+    unsigned colors[128];

+    uint8_t index[1 << 15];

+} Palette;

+

+typedef struct FlashSV2Context {

+    AVCodecContext *avctx;

+    uint8_t *current_frame;

+    uint8_t *key_frame;

+    AVFrame frame;

+    uint8_t *encbuffer;

+    uint8_t *keybuffer;

+    uint8_t *databuffer;

+

+    Block *frame_blocks;

+    Block *key_blocks;

+    int frame_size;

+    int blocks_size;

+

+    int use15_7, dist, comp;

+

+    int rows, cols;

+

+    int last_key_frame;

+

+    int image_width, image_height;

+    int block_width, block_height;

+    uint8_t flags;

+    uint8_t use_custom_palette;

+    uint8_t palette_type;       ///< 0=>default, 1=>custom - changed when palette regenerated.

+    Palette palette;

+#ifndef FLASHSV2_DUMB

+    double tot_blocks;          ///< blocks encoded since last keyframe

+    double diff_blocks;         ///< blocks that were different since last keyframe

+    double tot_lines;           ///< total scanlines in image since last keyframe

+    double diff_lines;          ///< scanlines that were different since last keyframe

+    double raw_size;            ///< size of raw frames since last keyframe

+    double comp_size;           ///< size of compressed data since last keyframe

+    double uncomp_size;         ///< size of uncompressed data since last keyframe

+

+    double total_bits;          ///< total bits written to stream so far

+#endif

+} FlashSV2Context;

+

+static av_cold void cleanup(FlashSV2Context * s)

+{

+    if (s->encbuffer)

+        av_free(s->encbuffer);

+    if (s->keybuffer)

+        av_free(s->keybuffer);

+    if (s->databuffer)

+        av_free(s->databuffer);

+    if (s->current_frame)

+        av_free(s->current_frame);

+    if (s->key_frame)

+        av_free(s->key_frame);

+

+    if (s->frame_blocks)

+        av_free(s->frame_blocks);

+    if (s->key_blocks)

+        av_free(s->key_blocks);

+}

+

+static void init_blocks(FlashSV2Context * s, Block * blocks,

+                        uint8_t * encbuf, uint8_t * databuf)

+{

+    int row, col;

+    Block *b;

+    for (col = 0; col < s->cols; col++) {

+        for (row = 0; row < s->rows; row++) {

+            b = blocks + (col + row * s->cols);

+            b->width = (col < s->cols - 1) ?

+                s->block_width :

+                s->image_width - col * s->block_width;

+

+            b->height = (row < s->rows - 1) ?

+                s->block_height :

+                s->image_height - row * s->block_height;

+

+            b->row   = row;

+            b->col   = col;

+            b->enc   = encbuf;

+            b->data  = databuf;

+            encbuf  += b->width * b->height * 3;

+            databuf += !databuf ? 0 : b->width * b->height * 6;

+        }

+    }

+}

+

+static void reset_stats(FlashSV2Context * s)

+{

+#ifndef FLASHSV2_DUMB

+    s->diff_blocks = 0.1;

+    s->tot_blocks = 1;

+    s->diff_lines = 0.1;

+    s->tot_lines = 1;

+    s->raw_size = s->comp_size = s->uncomp_size = 10;

+#endif

+}

+

+static av_cold int flashsv2_encode_init(AVCodecContext * avctx)

+{

+    FlashSV2Context *s = avctx->priv_data;

+

+    s->avctx = avctx;

+

+    s->comp = avctx->compression_level;

+    if (s->comp == -1)

+        s->comp = 9;

+    if (s->comp < 0 || s->comp > 9) {

+        av_log(avctx, AV_LOG_ERROR,

+               "Compression level should be 0-9, not %d\n", s->comp);

+        return -1;

+    }

+

+

+    if ((avctx->width > 4095) || (avctx->height > 4095)) {

+        av_log(avctx, AV_LOG_ERROR,

+               "Input dimensions too large, input must be max 4096x4096 !\n");

+        return -1;

+    }

+

+    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0)

+        return -1;

+

+

+    s->last_key_frame = 0;

+

+    s->image_width  = avctx->width;

+    s->image_height = avctx->height;

+

+    s->block_width  = (s->image_width /  12) & ~15;

+    s->block_height = (s->image_height / 12) & ~15;

+

+    s->rows = (s->image_height + s->block_height - 1) / s->block_height;

+    s->cols = (s->image_width +  s->block_width -  1) / s->block_width;

+

+    s->frame_size  = s->image_width * s->image_height * 3;

+    s->blocks_size = s->rows * s->cols * sizeof(Block);

+

+    s->encbuffer     = av_mallocz(s->frame_size);

+    s->keybuffer     = av_mallocz(s->frame_size);

+    s->databuffer    = av_mallocz(s->frame_size * 6);

+    s->current_frame = av_mallocz(s->frame_size);

+    s->key_frame     = av_mallocz(s->frame_size);

+    s->frame_blocks  = av_mallocz(s->blocks_size);

+    s->key_blocks    = av_mallocz(s->blocks_size);

+

+    init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);

+    init_blocks(s, s->key_blocks,   s->keybuffer, 0);

+    reset_stats(s);

+#ifndef FLASHSV2_DUMB

+    s->total_bits = 1;

+#endif

+

+    s->use_custom_palette =  0;

+    s->palette_type       = -1;        // so that the palette will be generated in reconfigure_at_keyframe

+

+    if (!s->encbuffer || !s->keybuffer || !s->databuffer

+        || !s->current_frame || !s->key_frame || !s->key_blocks

+        || !s->frame_blocks) {

+        av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");

+        cleanup(s);

+        return -1;

+    }

+

+    return 0;

+}

+

+static int new_key_frame(FlashSV2Context * s)

+{

+    int i;

+    FFSWAP(uint8_t * , s->keybuffer, s->encbuffer);

+    memcpy(s->key_blocks, s->frame_blocks, s->blocks_size);

+    memcpy(s->key_frame, s->current_frame, s->frame_size);

+

+    for (i = 0; i < s->rows * s->cols; i++) {

+        s->key_blocks[i].enc += (s->keybuffer - s->encbuffer);

+        s->key_blocks[i].sl_begin = 0;

+        s->key_blocks[i].sl_end   = 0;

+        s->key_blocks[i].data     = 0;

+    }

+

+    return 0;

+}

+

+static int write_palette(FlashSV2Context * s, uint8_t * buf, int buf_size)

+{

+    //this isn't implemented yet!  Default palette only!

+    return -1;

+}

+

+static int write_header(FlashSV2Context * s, uint8_t * buf, int buf_size)

+{

+    PutBitContext pb;

+    int buf_pos, len;

+

+    if (buf_size < 5)

+        return -1;

+

+    init_put_bits(&pb, buf, buf_size * 8);

+

+    put_bits(&pb, 4, (s->block_width  >> 4) - 1);

+    put_bits(&pb, 12, s->image_width);

+    put_bits(&pb, 4, (s->block_height >> 4) - 1);

+    put_bits(&pb, 12, s->image_height);

+

+    flush_put_bits(&pb);

+    buf_pos = 4;

+

+    buf[buf_pos++] = s->flags;

+

+    if (s->flags & HAS_PALLET_INFO) {

+        len = write_palette(s, buf + buf_pos, buf_size - buf_pos);

+        if (len < 0)

+            return -1;

+        buf_pos += len;

+    }

+

+    return buf_pos;

+}

+

+static int write_block(Block * b, uint8_t * buf, int buf_size)

+{

+    int buf_pos = 0;

+    unsigned block_size = b->data_size;

+

+    if (b->flags & HAS_DIFF_BLOCKS)

+        block_size += 2;

+    if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT)

+        block_size += 2;

+    if (block_size > 0)

+        block_size += 1;

+    if (buf_size < block_size + 2)

+        return -1;

+

+    buf[buf_pos++] = block_size >> 8;

+    buf[buf_pos++] = block_size;

+

+    if (block_size == 0)

+        return buf_pos;

+

+    buf[buf_pos++] = b->flags;

+

+    if (b->flags & HAS_DIFF_BLOCKS) {

+        buf[buf_pos++] = (uint8_t) (b->start);

+        buf[buf_pos++] = (uint8_t) (b->len);

+    }

+

+    if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT) {

+        //This feature of the format is poorly understood, and as of now, unused.

+        buf[buf_pos++] = (uint8_t) (b->col);

+        buf[buf_pos++] = (uint8_t) (b->row);

+    }

+

+    memcpy(buf + buf_pos, b->data, b->data_size);

+

+    buf_pos += b->data_size;

+

+    return buf_pos;

+}

+

+static int encode_zlib(Block * b, uint8_t * buf, unsigned long *buf_size, int comp)

+{

+    int res = compress2(buf, buf_size, b->sl_begin, b->sl_end - b->sl_begin, comp);

+    return res == Z_OK ? 0 : -1;

+}

+

+static int encode_zlibprime(Block * b, Block * prime, uint8_t * buf,

+                            int *buf_size, int comp)

+{

+    z_stream s;

+    int res;

+    s.zalloc = NULL;

+    s.zfree  = NULL;

+    s.opaque = NULL;

+    res = deflateInit(&s, comp);

+    if (res < 0)

+        return -1;

+

+    s.next_in  = prime->enc;

+    s.avail_in = prime->enc_size;

+    while (s.avail_in > 0) {

+        s.next_out  = buf;

+        s.avail_out = *buf_size;

+        res = deflate(&s, Z_SYNC_FLUSH);

+        if (res < 0)

+            return -1;

+    }

+

+    s.next_in   = b->sl_begin;

+    s.avail_in  = b->sl_end - b->sl_begin;

+    s.next_out  = buf;

+    s.avail_out = *buf_size;

+    res = deflate(&s, Z_FINISH);

+    deflateEnd(&s);

+    *buf_size -= s.avail_out;

+    if (res != Z_STREAM_END)

+        return -1;

+    return 0;

+}

+

+static int encode_bgr(Block * b, const uint8_t * src, int stride)

+{

+    int i;

+    uint8_t *ptr = b->enc;

+    for (i = 0; i < b->start; i++)

+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);

+    b->sl_begin = ptr + i * b->width * 3;

+    for (; i < b->start + b->len; i++)

+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);

+    b->sl_end = ptr + i * b->width * 3;

+    for (; i < b->height; i++)

+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);

+    b->enc_size = ptr + i * b->width * 3 - b->enc;

+    return b->enc_size;

+}

+

+static inline unsigned pixel_color15(const uint8_t * src)

+{

+    return (src[0] >> 3) | ((src[1] & 0xf8) << 2) | ((src[2] & 0xf8) << 7);

+}

+

+static inline unsigned int chroma_diff(unsigned int c1, unsigned int c2)

+{

+    unsigned int t1 = (c1 & 0x000000ff) + ((c1 & 0x0000ff00) >> 8) + ((c1 & 0x00ff0000) >> 16);

+    unsigned int t2 = (c2 & 0x000000ff) + ((c2 & 0x0000ff00) >> 8) + ((c2 & 0x00ff0000) >> 16);

+

+    return abs(t1 - t2) + abs((c1 & 0x000000ff) - (c2 & 0x000000ff)) +

+        abs(((c1 & 0x0000ff00) >> 8) - ((c2 & 0x0000ff00) >> 8)) +

+        abs(((c1 & 0x00ff0000) >> 16) - ((c2 & 0x00ff0000) >> 16));

+}

+

+static inline int pixel_color7_fast(Palette * palette, unsigned c15)

+{

+    return palette->index[c15];

+}

+

+static int pixel_color7_slow(Palette * palette, unsigned color)

+{

+    int i, min = 0x7fffffff;

+    int minc = -1;

+    for (i = 0; i < 128; i++) {

+        int c1 = palette->colors[i];

+        int diff = chroma_diff(c1, color);

+        if (diff < min) {

+            min = diff;

+            minc = i;

+        }

+    }

+    return minc;

+}

+

+static inline unsigned pixel_bgr(const uint8_t * src)

+{

+    return (src[0]) | (src[1] << 8) | (src[2] << 16);

+}

+

+static int write_pixel_15_7(Palette * palette, uint8_t * dest, const uint8_t * src,

+                            int dist)

+{

+    unsigned c15 = pixel_color15(src);

+    unsigned color = pixel_bgr(src);

+    int d15 = chroma_diff(color, color & 0x00f8f8f8);

+    int c7 = pixel_color7_fast(palette, c15);

+    int d7 = chroma_diff(color, palette->colors[c7]);

+    if (dist + d15 >= d7) {

+        dest[0] = (uint8_t) c7;

+        return 1;

+    } else {

+        dest[0] = 0x80 | (uint8_t) (c15 >> 8);

+        dest[1] = c15 & 0xff;

+        return 2;

+    }

+}

+

+static int update_palette_index(Palette * palette)

+{

+    int r, g, b;

+    unsigned int bgr, c15, index;

+    for (r = 4; r < 256; r += 8) {

+        for (g = 4; g < 256; g += 8) {

+            for (b = 4; b < 256; b += 8) {

+                bgr = b | (g << 8) | (r << 16);

+                c15 = (b >> 3) | ((g & 0xf8) << 2) | ((r & 0xf8) << 7);

+                index = pixel_color7_slow(palette, bgr);

+

+                palette->index[c15] = index;

+            }

+        }

+    }

+    return 0;

+}

+

+static const unsigned int default_screen_video_v2_palette[128] = {

+    0x00000000, 0x00333333, 0x00666666, 0x00999999, 0x00CCCCCC, 0x00FFFFFF,

+    0x00330000, 0x00660000, 0x00990000, 0x00CC0000, 0x00FF0000, 0x00003300,

+    0x00006600, 0x00009900, 0x0000CC00, 0x0000FF00, 0x00000033, 0x00000066,

+    0x00000099, 0x000000CC, 0x000000FF, 0x00333300, 0x00666600, 0x00999900,

+    0x00CCCC00, 0x00FFFF00, 0x00003333, 0x00006666, 0x00009999, 0x0000CCCC,

+    0x0000FFFF, 0x00330033, 0x00660066, 0x00990099, 0x00CC00CC, 0x00FF00FF,

+    0x00FFFF33, 0x00FFFF66, 0x00FFFF99, 0x00FFFFCC, 0x00FF33FF, 0x00FF66FF,

+    0x00FF99FF, 0x00FFCCFF, 0x0033FFFF, 0x0066FFFF, 0x0099FFFF, 0x00CCFFFF,

+    0x00CCCC33, 0x00CCCC66, 0x00CCCC99, 0x00CCCCFF, 0x00CC33CC, 0x00CC66CC,

+    0x00CC99CC, 0x00CCFFCC, 0x0033CCCC, 0x0066CCCC, 0x0099CCCC, 0x00FFCCCC,

+    0x00999933, 0x00999966, 0x009999CC, 0x009999FF, 0x00993399, 0x00996699,

+    0x0099CC99, 0x0099FF99, 0x00339999, 0x00669999, 0x00CC9999, 0x00FF9999,

+    0x00666633, 0x00666699, 0x006666CC, 0x006666FF, 0x00663366, 0x00669966,

+    0x0066CC66, 0x0066FF66, 0x00336666, 0x00996666, 0x00CC6666, 0x00FF6666,

+    0x00333366, 0x00333399, 0x003333CC, 0x003333FF, 0x00336633, 0x00339933,

+    0x0033CC33, 0x0033FF33, 0x00663333, 0x00993333, 0x00CC3333, 0x00FF3333,

+    0x00003366, 0x00336600, 0x00660033, 0x00006633, 0x00330066, 0x00663300,

+    0x00336699, 0x00669933, 0x00993366, 0x00339966, 0x00663399, 0x00996633,

+    0x006699CC, 0x0099CC66, 0x00CC6699, 0x0066CC99, 0x009966CC, 0x00CC9966,

+    0x0099CCFF, 0x00CCFF99, 0x00FF99CC, 0x0099FFCC, 0x00CC99FF, 0x00FFCC99,

+    0x00111111, 0x00222222, 0x00444444, 0x00555555, 0x00AAAAAA, 0x00BBBBBB,

+    0x00DDDDDD, 0x00EEEEEE

+};

+

+static int generate_default_palette(Palette * palette)

+{

+    memcpy(palette->colors, default_screen_video_v2_palette,

+           sizeof(default_screen_video_v2_palette));

+

+    return update_palette_index(palette);

+}

+

+static int generate_optimum_palette(Palette * palette, const uint8_t * image,

+                                   int width, int height, int stride)

+{

+    //this isn't implemented yet!  Default palette only!

+    return -1;

+}

+

+static inline int encode_15_7_sl(Palette * palette, uint8_t * dest,

+                                 const uint8_t * src, int width, int dist)

+{

+    int len = 0, x;

+    for (x = 0; x < width; x++) {

+        len += write_pixel_15_7(palette, dest + len, src + 3 * x, dist);

+    }

+    return len;

+}

+

+static int encode_15_7(Palette * palette, Block * b, const uint8_t * src,

+                       int stride, int dist)

+{

+    int i;

+    uint8_t *ptr = b->enc;

+    for (i = 0; i < b->start; i++)

+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);

+    b->sl_begin = ptr;

+    for (; i < b->start + b->len; i++)

+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);

+    b->sl_end = ptr;

+    for (; i < b->height; i++)

+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);

+    b->enc_size = ptr - b->enc;

+    return b->enc_size;

+}

+

+static int encode_block(Palette * palette, Block * b, Block * prev,

+                        const uint8_t * src, int stride, int comp, int dist,

+                        int keyframe)

+{

+    unsigned buf_size = b->width * b->height * 6;

+    uint8_t buf[buf_size];

+    int res;

+    if (b->flags & COLORSPACE_15_7) {

+        encode_15_7(palette, b, src, stride, dist);

+    } else {

+        encode_bgr(b, src, stride);

+    }

+

+    if (b->len > 0) {

+        b->data_size = buf_size;

+        res = encode_zlib(b, b->data, &b->data_size, comp);

+        if (res)

+            return res;

+

+        if (!keyframe) {

+            res = encode_zlibprime(b, prev, buf, &buf_size, comp);

+            if (res)

+                return res;

+

+            if (buf_size < b->data_size) {

+                b->data_size = buf_size;

+                memcpy(b->data, buf, buf_size);

+                b->flags |= ZLIB_PRIME_COMPRESS_PREVIOUS;

+            }

+        }

+    } else {

+        b->data_size = 0;

+    }

+    return 0;

+}

+

+static int compare_sl(FlashSV2Context * s, Block * b, const uint8_t * src,

+                      uint8_t * frame, uint8_t * key, int y, int keyframe)

+{

+    if (memcmp(src, frame, b->width * 3) != 0) {

+        b->dirty = 1;

+        memcpy(frame, src, b->width * 3);

+#ifndef FLASHSV2_DUMB

+        s->diff_lines++;

+#endif

+    }

+    if (memcmp(src, key, b->width * 3) != 0) {

+        if (b->len == 0)

+            b->start = y;

+        b->len = y + 1 - b->start;

+    }

+    return 0;

+}

+

+static int mark_all_blocks(FlashSV2Context * s, const uint8_t * src, int stride,

+                           int keyframe)

+{

+    int sl, rsl, col, pos, possl;

+    Block *b;

+    for (sl = s->image_height - 1; sl >= 0; sl--) {

+        for (col = 0; col < s->cols; col++) {

+            rsl = s->image_height - sl - 1;

+            b = s->frame_blocks + col + rsl / s->block_height * s->cols;

+            possl = stride * sl + col * s->block_width * 3;

+            pos = s->image_width * rsl * 3 + col * s->block_width * 3;

+            compare_sl(s, b, src + possl, s->current_frame + pos,

+                       s->key_frame + pos, rsl % s->block_height, keyframe);

+        }

+    }

+#ifndef FLASHSV2_DUMB

+    s->tot_lines += s->image_height * s->cols;

+#endif

+    return 0;

+}

+

+static int encode_all_blocks(FlashSV2Context * s, int keyframe)

+{

+    int row, col, res;

+    uint8_t *data;

+    Block *b, *prev;

+    for (row = 0; row < s->rows; row++) {

+        for (col = 0; col < s->cols; col++) {

+            b = s->frame_blocks + (row * s->cols + col);

+            prev = s->key_blocks + (row * s->cols + col);

+            if (keyframe) {

+                b->start = 0;

+                b->len = b->height;

+                b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;

+            } else if (!b->dirty) {

+                b->start = 0;

+                b->len = 0;

+                b->data_size = 0;

+                b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;

+                continue;

+            } else {

+                b->flags = s->use15_7 ? COLORSPACE_15_7 | HAS_DIFF_BLOCKS : HAS_DIFF_BLOCKS;

+            }

+            data = s->current_frame + s->image_width * 3 * s->block_height * row + s->block_width * col * 3;

+            res = encode_block(&s->palette, b, prev, data, s->image_width * 3, s->comp, s->dist, keyframe);

+#ifndef FLASHSV2_DUMB

+            if (b->dirty)

+                s->diff_blocks++;

+            s->comp_size += b->data_size;

+            s->uncomp_size += b->enc_size;

+#endif

+            if (res)

+                return res;

+        }

+    }

+#ifndef FLASHSV2_DUMB

+    s->raw_size += s->image_width * s->image_height * 3;

+    s->tot_blocks += s->rows * s->cols;

+#endif

+    return 0;

+}

+

+static int write_all_blocks(FlashSV2Context * s, uint8_t * buf,

+                            int buf_size)

+{

+    int row, col, buf_pos = 0, len;

+    Block *b;

+    for (row = 0; row < s->rows; row++) {

+        for (col = 0; col < s->cols; col++) {

+            b = s->frame_blocks + row * s->cols + col;

+            len = write_block(b, buf + buf_pos, buf_size - buf_pos);

+            b->start = b->len = b->dirty = 0;

+            if (len < 0)

+                return len;

+            buf_pos += len;

+        }

+    }

+    return buf_pos;

+}

+

+static int write_bitstream(FlashSV2Context * s, const uint8_t * src, int stride,

+                           uint8_t * buf, int buf_size, int keyframe)

+{

+    int buf_pos, res;

+

+    res = mark_all_blocks(s, src, stride, keyframe);

+    if (res)

+        return res;

+    res = encode_all_blocks(s, keyframe);

+    if (res)

+        return res;

+

+    res = write_header(s, buf, buf_size);

+    if (res < 0) {

+        return res;

+    } else {

+        buf_pos = res;

+    }

+    res = write_all_blocks(s, buf + buf_pos, buf_size - buf_pos);

+    if (res < 0)

+        return res;

+    buf_pos += res;

+#ifndef FLASHSV2_DUMB

+    s->total_bits += ((double) buf_pos) * 8.0;

+#endif

+

+    return buf_pos;

+}

+

+static void recommend_keyframe(FlashSV2Context * s, int *keyframe)

+{

+#ifndef FLASHSV2_DUMB

+    double block_ratio, line_ratio, enc_ratio, comp_ratio, data_ratio;

+    if (s->avctx->gop_size > 0) {

+        block_ratio = s->diff_blocks / s->tot_blocks;

+        line_ratio = s->diff_lines / s->tot_lines;

+        enc_ratio = s->uncomp_size / s->raw_size;

+        comp_ratio = s->comp_size / s->uncomp_size;

+        data_ratio = s->comp_size / s->raw_size;

+

+        if ((block_ratio >= 0.5 && line_ratio / block_ratio <= 0.5) || line_ratio >= 0.95) {

+            *keyframe = 1;

+            return;

+        }

+    }

+#else

+    return;

+#endif

+}

+

+static const double block_size_fraction = 1.0 / 300;

+static int optimum_block_width(FlashSV2Context * s)

+{

+#ifndef FLASHSV2_DUMB

+    double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;

+    double width = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_width;

+    int pwidth = ((int) width);

+    return FFCLIP(pwidth & ~15, 256, 16);

+#else

+    return 64;

+#endif

+}

+

+static int optimum_block_height(FlashSV2Context * s)

+{

+#ifndef FLASHSV2_DUMB

+    double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;

+    double height = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_height;

+    int pheight = ((int) height);

+    return FFCLIP(pheight & ~15, 256, 16);

+#else

+    return 64;

+#endif

+}

+

+static const double use15_7_threshold = 8192;

+

+static int optimum_use15_7(FlashSV2Context * s)

+{

+#ifndef FLASHSV2_DUMB

+    double ideal = ((double)(s->avctx->bit_rate * s->avctx->time_base.den * s->avctx->ticks_per_frame)) /

+        ((double) s->avctx->time_base.num) * s->avctx->frame_number;

+    if (ideal + use15_7_threshold < s->total_bits) {

+        return 1;

+    } else {

+        return 0;

+    }

+#else

+    return s->avctx->global_quality == 0;

+#endif

+}

+

+static const double color15_7_factor = 100;

+

+static int optimum_dist(FlashSV2Context * s)

+{

+#ifndef FLASHSV2_DUMB

+    double ideal =

+        s->avctx->bit_rate * s->avctx->time_base.den *

+        s->avctx->ticks_per_frame;

+    int dist = pow((s->total_bits / ideal) * color15_7_factor, 3);

+    av_log(s->avctx, AV_LOG_DEBUG, "dist: %d\n", dist);

+    return dist;

+#else

+    return 15;

+#endif

+}

+

+

+static int reconfigure_at_keyframe(FlashSV2Context * s, const uint8_t * image,

+                                   int stride)

+{

+    int update_palette = 0;

+    int res;

+    s->block_width = optimum_block_width(s);

+    s->block_height = optimum_block_height(s);

+

+    s->rows = (s->image_height + s->block_height - 1) / s->block_height;

+    s->cols = (s->image_width +  s->block_width -  1) / s->block_width;

+

+    if (s->rows * s->cols != s->blocks_size / sizeof(Block)) {

+        if (s->rows * s->cols > s->blocks_size / sizeof(Block)) {

+            s->frame_blocks = av_realloc(s->frame_blocks, s->rows * s->cols * sizeof(Block));

+            s->key_blocks = av_realloc(s->key_blocks, s->cols * s->rows * sizeof(Block));

+            if (!s->frame_blocks || !s->key_blocks) {

+                av_log(s->avctx, AV_LOG_ERROR, "Memory allocation failed.\n");

+                return -1;

+            }

+            s->blocks_size = s->rows * s->cols * sizeof(Block);

+        }

+        init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);

+        init_blocks(s, s->key_blocks, s->keybuffer, 0);

+

+    }

+

+    s->use15_7 = optimum_use15_7(s);

+    if (s->use15_7) {

+        if ((s->use_custom_palette && s->palette_type != 1) || update_palette) {

+            res = generate_optimum_palette(&s->palette, image, s->image_width, s->image_height, stride);

+            if (res)

+                return res;

+            s->palette_type = 1;

+            av_log(s->avctx, AV_LOG_DEBUG, "Generated optimum palette\n");

+        } else if (!s->use_custom_palette && s->palette_type != 0) {

+            res = generate_default_palette(&s->palette);

+            if (res)

+                return res;

+            s->palette_type = 0;

+            av_log(s->avctx, AV_LOG_DEBUG, "Generated default palette\n");

+        }

+    }

+

+

+    reset_stats(s);

+

+    return 0;

+}

+

+static int flashsv2_encode_frame(AVCodecContext * avctx, uint8_t * buf,

+                                 int buf_size, void *data)

+{

+    FlashSV2Context *const s = avctx->priv_data;

+    AVFrame *pict = data;

+    AVFrame *const p = &s->frame;

+    int res;

+    int keyframe = 0;

+

+    *p = *pict;

+

+    /* First frame needs to be a keyframe */

+    if (avctx->frame_number == 0)

+        keyframe = 1;

+

+    /* Check the placement of keyframes */

+    if (avctx->gop_size > 0) {

+        if (avctx->frame_number >= s->last_key_frame + avctx->gop_size)

+            keyframe = 1;

+    }

+

+    if (buf_size < s->frame_size) {

+        //Conservative upper bound check for compressed data

+        av_log(avctx, AV_LOG_ERROR, "buf_size %d <  %d\n", buf_size, s->frame_size);

+        return -1;

+    }

+

+    if (!keyframe

+        && avctx->frame_number > s->last_key_frame + avctx->keyint_min) {

+        recommend_keyframe(s, &keyframe);

+        if (keyframe)

+            av_log(avctx, AV_LOG_DEBUG, "Recommending key frame at frame %d\n", avctx->frame_number);

+    }

+

+    if (keyframe) {

+        res = reconfigure_at_keyframe(s, p->data[0], p->linesize[0]);

+        if (res)

+            return res;

+    }

+

+    if (s->use15_7)

+        s->dist = optimum_dist(s);

+

+    res = write_bitstream(s, p->data[0], p->linesize[0], buf, buf_size, keyframe);

+

+    if (keyframe) {

+        new_key_frame(s);

+        p->pict_type = FF_I_TYPE;

+        p->key_frame = 1;

+        s->last_key_frame = avctx->frame_number;

+        av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n", avctx->frame_number);

+    } else {

+        p->pict_type = FF_P_TYPE;

+        p->key_frame = 0;

+    }

+

+    avctx->coded_frame = p;

+

+    return res;

+}

+

+static av_cold int flashsv2_encode_end(AVCodecContext * avctx)

+{

+    FlashSV2Context *s = avctx->priv_data;

+

+    cleanup(s);

+

+    return 0;

+}

+

+AVCodec flashsv2_encoder = {

+    "flashsv2",

+    CODEC_TYPE_VIDEO,

+    CODEC_ID_FLASHSV2,

+    sizeof(FlashSV2Context),

+    flashsv2_encode_init,

+    flashsv2_encode_frame,

+    flashsv2_encode_end,

+    .pix_fmts = (enum PixelFormat[]) {PIX_FMT_BGR24, PIX_FMT_NONE},

+    .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video Version 2"),

+};

Index: doc/general.texi

===================================================================

--- doc/general.texi       (revision 19479)

+++ doc/general.texi    (working copy)

@@ -350,6 +350,7 @@

     @tab experimental lossless codec (fourcc: FFV1)

 @item Flash Screen Video v1  @tab  X  @tab  X

     @tab fourcc: FSV1

+ at item<https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel> Flash Screen Video v2  @tab  X

 @item Flash Video (FLV)      @tab  X  @tab  X

     @tab Sorenson H.263 used in Flash

 @item Fraps                  @tab     @tab  X

Index: libavformat/flvenc.c

===================================================================

--- libavformat/flvenc.c                   (revision 19479)

+++ libavformat/flvenc.c                (working copy)

@@ -29,6 +29,7 @@

 static const AVCodecTag flv_video_codec_ids[] = {

     {CODEC_ID_FLV1,    FLV_CODECID_H263  },

     {CODEC_ID_FLASHSV, FLV_CODECID_SCREEN},

+    {CODEC_ID_FLASHSV2, FLV_CODECID_SCREEN2},

     {CODEC_ID_VP6F,    FLV_CODECID_VP6   },

     {CODEC_ID_VP6,     FLV_CODECID_VP6   },

     {CODEC_ID_H264,    FLV_CODECID_H264  },


Regards,
Leon





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