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[FFmpeg-devel] lavc/mjpegdec: Support 2:3 subsampling

Message ID CAB0OVGpAGqoppVAVQ8R+5C1qmA5=eWu3Rv9-7s_WiK38hZfxPQ@mail.gmail.com
State Superseded
Headers show

Commit Message

Carl Eugen Hoyos Oct. 16, 2018, 10:22 p.m. UTC 
Hi!

Attached patch allows decoding the sample from ticket #7495.

Please review, Carl Eugen
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Patch

From 0e9d2ec4e0cba36ba03a6b7470a707c0a3f88b8c Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <ceffmpeg@gmail.com>
Date: Wed, 17 Oct 2018 00:21:26 +0200
Subject: [PATCH] lavc/mjpegdec: Support 2:3 subsampling.

Fixes ticket #7495.
---
 libavcodec/mjpegdec.c |   17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 35ee10d..0a81c0e 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -594,6 +594,7 @@  int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
         s->avctx->color_range = s->cs_itu601 ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
         break;
     case 0x22111100:
+    case 0x23111100:
     case 0x42111100:
     case 0x24111100:
         if (s->bits <= 8) s->avctx->pix_fmt = s->cs_itu601 ? AV_PIX_FMT_YUV420P : AV_PIX_FMT_YUVJ420P;
@@ -607,6 +608,10 @@  int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
             if (s->bits > 8)
                 goto unk_pixfmt;
             s->upscale_v[1] = s->upscale_v[2] = 1;
+        } else if (pix_fmt_id = 0x23111100) {
+            if (s->bits > 8)
+                goto unk_pixfmt;
+            s->upscale_v[1] = s->upscale_v[2] = 2;
         }
         break;
     case 0x41111100:
@@ -2592,9 +2597,15 @@  the_end:
             }
             dst = &((uint8_t *)s->picture_ptr->data[p])[(h - 1) * s->linesize[p]];
             for (i = h - 1; i; i--) {
-                uint8_t *src1 = &((uint8_t *)s->picture_ptr->data[p])[i / 2 * s->linesize[p]];
-                uint8_t *src2 = &((uint8_t *)s->picture_ptr->data[p])[(i + 1) / 2 * s->linesize[p]];
-                if (src1 == src2 || i == h - 1) {
+                 uint8_t *src1, *src2;
+                if (s->upscale_v[p] == 2) {
+                    src1 = &((uint8_t *)s->picture_ptr->data[p])[i * 2 / 3 * s->linesize[p]];
+                    src2 = &((uint8_t *)s->picture_ptr->data[p])[(i + 1) * 2 / 3 * s->linesize[p]];
+                } else {
+                    src1 = &((uint8_t *)s->picture_ptr->data[p])[i / 2 * s->linesize[p]];
+                    src2 = &((uint8_t *)s->picture_ptr->data[p])[(i + 1) / 2 * s->linesize[p]];
+                }
+                if (s->upscale_v[p] != 2 && (src1 == src2 || i == h - 1)) {
                     memcpy(dst, src1, w);
                 } else {
                     for (index = 0; index < w; index++)
-- 
1.7.10.4