Autodetect jpg images.

Based on 2d3842f5 by Michael Niedermayer.

Fixes ticket #2541.

1 files changed, 52 insertions, 0 deletions

diff --git a/libavformat/img2dec.c b/libavformat/img2dec.c
index 70bef9d405..16bd699c98 100644
--- a/libavformat/img2dec.c
+++ b/libavformat/img2dec.c
@@ -620,6 +620,57 @@ static int j2k_probe(AVProbeData *p)
     return 0;
 }
 
+static int jpeg_probe(AVProbeData *p)
+{
+    const uint8_t *b = p->buf;
+    int i, state = 0xD8;
+
+    if (AV_RB16(b) != 0xFFD8 ||
+        AV_RB32(b) == 0xFFD8FFF7)
+    return 0;
+
+    b += 2;
+    for (i = 0; i < p->buf_size - 2; i++) {
+        int c;
+        if (b[i] != 0xFF)
+            continue;
+        c = b[i + 1];
+        switch (c) {
+        case 0xD8:
+            return 0;
+        case 0xC0:
+        case 0xC1:
+        case 0xC2:
+        case 0xC3:
+        case 0xC5:
+        case 0xC6:
+        case 0xC7:
+            if (state != 0xD8)
+                return 0;
+            state = 0xC0;
+            break;
+        case 0xDA:
+            if (state != 0xC0)
+                return 0;
+            state = 0xDA;
+            break;
+        case 0xD9:
+            if (state != 0xDA)
+                return 0;
+            state = 0xD9;
+            break;
+        default:
+            if (  (c >= 0x02 && c <= 0xBF)
+                || c == 0xC8)
+                return 0;
+        }
+    }
+
+    if (state == 0xD9)
+        return AVPROBE_SCORE_EXTENSION + 1;
+    return AVPROBE_SCORE_EXTENSION / 8;
+}
+
 static int jpegls_probe(AVProbeData *p)
 {
     const uint8_t *b = p->buf;
@@ -711,6 +762,7 @@ IMAGEAUTO_DEMUXER(bmp,     AV_CODEC_ID_BMP)
 IMAGEAUTO_DEMUXER(dpx,     AV_CODEC_ID_DPX)
 IMAGEAUTO_DEMUXER(exr,     AV_CODEC_ID_EXR)
 IMAGEAUTO_DEMUXER(j2k,     AV_CODEC_ID_JPEG2000)
+IMAGEAUTO_DEMUXER(jpeg,    AV_CODEC_ID_MJPEG)
 IMAGEAUTO_DEMUXER(jpegls,  AV_CODEC_ID_JPEGLS)
 IMAGEAUTO_DEMUXER(pictor,  AV_CODEC_ID_PICTOR)
 IMAGEAUTO_DEMUXER(png,     AV_CODEC_ID_PNG)