On Tue, Mar 24, 2015 at 4:07 PM, greeshma <greeshmabalaba...@gmail.com>
wrote:
> The patch is made and FATE tests are done.It accepted, will submit with
> the copyrights and signature.The code is written based on openEXR
> algorithm of B44 lossy compression and modified according to the FFmpeg
> code.
>
>
> From 9670e283f38b71c06457c976f3f2040c8d38bbd9 Mon Sep 17 00:00:00 2001
> From: greeshmab <greeshmabalaba...@gmail.com>
> Date: Tue, 24 Mar 2015 12:36:21 +0530
> Subject: [PATCH] A new exr lossy compression technique B44 is added
>
> ---
> libavcodec/exr.c | 121
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 121 insertions(+)
>
> diff --git a/libavcodec/exr.c b/libavcodec/exr.c
> index 6251fb7..b7114be 100644
> --- a/libavcodec/exr.c
> +++ b/libavcodec/exr.c
> @@ -770,6 +770,124 @@ static int piz_uncompress(EXRContext *s, const
> uint8_t *src, int ssize,
> return 0;
> }
>
> +
> +static void B44_unpack14 ( GetByteContext *gb, uint16_t out[16]){
> + uint16_t shift;
> + const uint8_t *r = gb->buffer;
> + av_assert0(r[2] != 0xfc);
> + out[0] = (r[0] << 8) | r[1];
> + shift = (r[2] >> 2);
> + out[ 1] = out[ 0] + ((r[ 5] >> 2) << shift);
> + out[ 2] = out[ 1] + ((r[ 8] >> 2) << shift);
> + out[ 3] = out[ 2] + ((r[11] >> 2) << shift);
> + out[ 4] = out[ 0] + (((r[ 2] << 4) | (r[ 3] >> 4)) << shift);
> + out[ 5] = out[ 4] + (((r[ 5] << 4) | (r[ 6] >> 4)) << shift);
> + out[ 6] = out[ 5] + (((r[ 8] << 4) | (r[ 9] >> 4)) << shift);
> + out[ 7] = out[ 6] + (((r[11] << 4) | (r[12] >> 4)) << shift);
> + out[ 8] = out[ 4] + (((r[ 3] << 2) | (r[ 4] >> 6)) << shift);
> + out[ 9] = out[ 8] + (((r[ 6] << 2) | (r[ 7] >> 6)) << shift);
> + out[10] = out[ 9] + (((r[ 9] << 2) | (r[10] >> 6)) << shift);
> + out[11] = out[10] + (((r[12] << 2) | (r[13] >> 6)) << shift);
> + out[12] = out[ 8] + (r[ 4] << shift);
> + out[13] = out[12] + (r[ 7] << shift);
> + out[14] = out[13] + (r[10] << shift);
> + out[15] = out[14] + (r[13] << shift);
> + for (int i = 0; i < 16; ++i) { //if any out value
> exceeds 16bits
> + if (out[i] & 0x8000)
> + out[i] &= 0x7fff;
> + else
> + out[i] = ~out[i];
> + }
> +}
> +
> +
> +static void B44_unpack3 ( GetByteContext *gb, uint16_t out[16]){
> + const uint8_t *r = gb->buffer;
> //pixels have the same value
> + av_assert0(r[2] == 0xfc);
> + out[0] = (r[0] << 8) | r[1];
> + if (out[0] & 0x8000)
> + out[0] &= 0x7fff;
> + else
> + out[0] = ~out[0];
> + for (int i = 1; i < 16; ++i)
> + out[i] = out[0];
> +}
> +
> +
> +
> +static int b44_uncompress(EXRContext *s, const uint8_t *src,int ssize,
> int dsize, EXRThreadData *td)
> +
> +{
> + GetByteContext gb;
> + unsigned long dest_len = dsize;
> + uint8_t *out;
> + int i, j;
> + uint16_t *tmp = (uint16_t *)td->tmp;
> + out = td->uncompressed_data;
> + bytestream2_init(&gb, src, ssize);
> + if (uncompress(td->tmp, &dest_len, src, ssize) != Z_OK || dest_len !=
> dsize)
> + return AVERROR_INVALIDDATA;
> + for (i = 0; i < s->nb_channels; i++) {
> + EXRChannel *channel = &s->channels[i];
> + int size = channel->pixel_type;
> + int inSize = ssize;
> + if (channel->pixel_type != EXR_HALF) { // UINT or
> FLOAT channel.
> + int n = s->xdelta * s->ydelta * size * sizeof (*tmp);
> + memcpy (tmp, gb.buffer, n);
> + gb.buffer += n;
> + inSize -= n;
> + continue;
> + } else { //EXR_HALF
> Channel
> + for (int y=0; y < s->ydelta; y +=4 ) {
> + uint16_t *row0 = tmp + y * s->xdelta;
> + uint16_t *row1 = row0 + s->xdelta;
> + uint16_t *row2 = row1 + s->xdelta;
> + uint16_t *row3 = row2 + s->xdelta;
> + for (int x = 0; x < s->xdelta; x += 4) {
> + uint16_t out[16];
> + int num = (x + 3 < s->xdelta)? 4 * sizeof (*out) :
> (s->xdelta - x) * sizeof (*out);
> + if (gb.buffer[2] == 0xfc) {
> + B44_unpack3 (&gb, out);
> + gb.buffer += 3;
> + inSize -= 3;
> + } else {
> + B44_unpack14 (&gb, out);
> + gb.buffer += 14;
> + inSize -= 14;
> + }
> + if (y + 3 < s->ydelta) {
> + memcpy (row0, &out[ 0], num);
> + memcpy (row1, &out[ 4], num);
> + memcpy (row2, &out[ 8], num);
> + memcpy (row3, &out[12], num);
> + } else {
> + memcpy (row0, &out[ 0], num);
> + if (y + 1 < s->ydelta)
> + memcpy (row1, &out[ 4], num);
> + if (y + 2 < s->ydelta)
> + memcpy (row2, &out[ 8], num);
> + }
> + row0 += 4;
> + row1 += 4;
> + row2 += 4;
> + row3 += 4;
> + }
> + }
> + }
> + }
> + for (i = 0; i < s->ysize; i++) {
> + for (j = 0; j < s->nb_channels; j++) {
> + uint16_t *in = tmp + j * s->xdelta * s->ysize + i * s->xdelta;
> + memcpy(out, in, s->xdelta * 2);
> + out += s->xdelta * 2;
> + }
> + }
> + return 0;
> +}
> +
> +
> +
> static int pxr24_uncompress(EXRContext *s, const uint8_t *src,
> int compressed_size, int uncompressed_size,
> EXRThreadData *td)
> @@ -888,6 +1006,8 @@ static int decode_block(AVCodecContext *avctx, void
> *tdata,
> break;
> case EXR_RLE:
> ret = rle_uncompress(src, data_size, uncompressed_size, td);
> + case EXR_B44:
> + ret = b44_uncompress(s, src, data_size, uncompressed_size,
> td);
> }
> if (ret < 0) {
> av_log(avctx, AV_LOG_ERROR, "decode_block() failed.\n");
> @@ -1282,6 +1402,7 @@ static int decode_frame(AVCodecContext *avctx, void
> *data,
> s->scan_lines_per_block = 16;
> break;
> case EXR_PIZ:
> + case EXR_B44:
> s->scan_lines_per_block = 32;
> break;
> default:
> --
> 2.1.4
>
>
>
> Greeshma
>
>
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