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lavc/mjpegdec: Decode Huffman-coded lossless JPEGs embedded in DNGs

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Main image data in DNGs is usually comprised of tiles, each of which is a Huffman-encoded lossless JPEG.

Tested for ljpeg regressions with:
`ffmpeg -f lavfi -i testsrc=d=1 -vcodec ljpeg test.avi`
`ffmpeg test.avi out.avi`
The modified code in ljpeg_decode_rgb_scan runs without issues.

Signed-off-by: Nick Renieris <velocityra@gmail.com>
This commit is contained in:
Nick Renieris 2019-08-29 16:10:40 +03:00 committed by Paul B Mahol
parent 2a21487b9e
commit 40abff05d2
2 changed files with 46 additions and 7 deletions
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52
libavcodec/mjpegdec.c
View File

@ -412,6 +412,14 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
return AVERROR_PATCHWELCOME;
}
/* Lossless JPEGs encoded in DNGs are commonly bayer-encoded. They contain 2
interleaved components and the width stored in their SOF3 markers is the
width of each one. We only output a single component, therefore we need
to adjust the output image width. */
if (s->lossless == 1 && nb_components == 2) {
s->bayer = 1;
width *= 2;
}
/* if different size, realloc/alloc picture */
if (width != s->width || height != s->height || bits != s->bits ||
@ -488,6 +496,9 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
}
switch (pix_fmt_id) {
case 0x11110000: /* for bayer-encoded huffman lossless JPEGs embedded in DNGs */
s->avctx->pix_fmt = AV_PIX_FMT_GRAY16LE;
break;
case 0x11111100:
if (s->rgb)
s->avctx->pix_fmt = s->bits <= 9 ? AV_PIX_FMT_BGR24 : AV_PIX_FMT_BGR48;
@ -1041,17 +1052,20 @@ static int handle_rstn(MJpegDecodeContext *s, int nb_components)
return reset;
}
/* Handles 1 to 4 components */
static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int predictor, int point_transform)
{
int i, mb_x, mb_y;
unsigned width;
uint16_t (*buffer)[4];
int left[4], top[4], topleft[4];
const int linesize = s->linesize[0];
const int mask = ((1 << s->bits) - 1) << point_transform;
int resync_mb_y = 0;
int resync_mb_x = 0;
int vpred[6];
if (s->nb_components != 3 && s->nb_components != 4)
if (s->nb_components <= 0 || s->nb_components > 4)
return AVERROR_INVALIDDATA;
if (s->v_max != 1 || s->h_max != 1 || !s->lossless)
return AVERROR_INVALIDDATA;
@ -1059,8 +1073,15 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
s->restart_count = s->restart_interval;
av_fast_malloc(&s->ljpeg_buffer, &s->ljpeg_buffer_size,
(unsigned)s->mb_width * 4 * sizeof(s->ljpeg_buffer[0][0]));
if (s->restart_interval == 0)
s->restart_interval = INT_MAX;
if (s->bayer)
width = s->mb_width / nb_components; /* Interleaved, width stored is the total so need to divide */
else
width = s->mb_width;
av_fast_malloc(&s->ljpeg_buffer, &s->ljpeg_buffer_size, width * 4 * sizeof(s->ljpeg_buffer[0][0]));
if (!s->ljpeg_buffer)
return AVERROR(ENOMEM);
@ -1078,7 +1099,12 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
for (i = 0; i < 4; i++)
top[i] = left[i] = topleft[i] = buffer[0][i];
for (mb_x = 0; mb_x < s->mb_width; mb_x++) {
if ((mb_y * s->width) % s->restart_interval == 0) {
for (i = 0; i < 6; i++)
vpred[i] = 1 << (s->bits-1);
}
for (mb_x = 0; mb_x < width; mb_x++) {
int modified_predictor = predictor;
if (get_bits_left(&s->gb) < 1) {
@ -1102,12 +1128,19 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
topleft[i] = top[i];
top[i] = buffer[mb_x][i];
PREDICT(pred, topleft[i], top[i], left[i], modified_predictor);
dc = mjpeg_decode_dc(s, s->dc_index[i]);
if(dc == 0xFFFFF)
return -1;
if (!s->bayer || mb_x) {
pred = left[i];
} else { /* This path runs only for the first line in bayer images */
vpred[i] += dc;
pred = vpred[i] - dc;
}
PREDICT(pred, topleft[i], top[i], pred, modified_predictor);
left[i] = buffer[mb_x][i] =
mask & (pred + (unsigned)(dc * (1 << point_transform)));
}
@ -1151,6 +1184,11 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
ptr[3*mb_x + 0] = buffer[mb_x][1] + ptr[3*mb_x + 1];
ptr[3*mb_x + 2] = buffer[mb_x][2] + ptr[3*mb_x + 1];
}
} else if (s->bayer && nb_components == 2) {
for (mb_x = 0; mb_x < width; mb_x++) {
((uint16_t*)ptr)[2*mb_x + 0] = buffer[mb_x][0];
((uint16_t*)ptr)[2*mb_x + 1] = buffer[mb_x][1];
}
} else {
for(i=0; i<nb_components; i++) {
int c= s->comp_index[i];
@ -1695,7 +1733,7 @@ next_field:
point_transform, ilv)) < 0)
return ret;
} else {
if (s->rgb) {
if (s->rgb || s->bayer) {
if ((ret = ljpeg_decode_rgb_scan(s, nb_components, predictor, point_transform)) < 0)
return ret;
} else {

1
libavcodec/mjpegdec.h
View File

@ -64,6 +64,7 @@ typedef struct MJpegDecodeContext {
int lossless;
int ls;
int progressive;
int bayer; /* true if it's a bayer-encoded JPEG embedded in a DNG */
int rgb;
uint8_t upscale_h[4];
uint8_t upscale_v[4];