[FFmpeg-devel] [PATCH] libavcodec/jpeg2000dec: Support for PPM marker

[gautamramk at gmail.com]

From: Gautam Ramakrishnan <gautamramk at gmail.com>

This patch adds support for PPM marker for JPEG2000
decoder. It allows the sample p1_03.j2k to be decoded.
---
 libavcodec/jpeg2000dec.c | 78 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 3 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index b7766459c4..4e66ebf7c6 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -71,6 +71,7 @@ typedef struct Jpeg2000POC {
 typedef struct Jpeg2000TilePart {
     uint8_t tile_index;                 // Tile index who refers the tile-part
     const uint8_t *tp_end;
+    GetByteContext header_tpg;          // bit stream of header if PPM header is used
     GetByteContext tpg;                 // bit stream in tile-part
 } Jpeg2000TilePart;
 
@@ -102,6 +103,13 @@ typedef struct Jpeg2000DecoderContext {
     uint8_t         cbps[4];    // bits per sample in particular components
     uint8_t         sgnd[4];    // if a component is signed
     uint8_t         properties[4];
+
+    uint8_t         has_ppm;
+    uint8_t         *packed_headers; // contains packed headers. Used only along with PPM marker
+    int             packed_headers_size;
+    GetByteContext  packed_headers_stream;
+    uint8_t         in_tile_headers;
+
     int             cdx[4], cdy[4];
     int             precision;
     int             ncomponents;
@@ -901,6 +909,31 @@ static int get_plt(Jpeg2000DecoderContext *s, int n)
     return 0;
 }
 
+static int get_ppm(Jpeg2000DecoderContext *s, int n)
+{
+    void *new;
+
+    if (n < 3) {
+        av_log(s->avctx, AV_LOG_ERROR, "Invalid length for PPM data.\n");
+        return AVERROR_INVALIDDATA;
+    }
+    s->has_ppm = 1;
+    bytestream2_get_byte(&s->g); //Zppm is skipped and not used
+    new = av_realloc(s->packed_headers,
+                     s->packed_headers_size + n - 3);
+    if (new) {
+        s->packed_headers = new;
+    } else
+        return AVERROR(ENOMEM);
+    memset(&s->packed_headers_stream, 0, sizeof(s->packed_headers_stream));
+    memcpy(s->packed_headers + s->packed_headers_size,
+           s->g.buffer, n - 3);
+    s->packed_headers_size += n - 3;
+    bytestream2_skip(&s->g, n - 3);
+
+    return 0;
+}
+
 static int get_ppt(Jpeg2000DecoderContext *s, int n)
 {
     Jpeg2000Tile *tile;
@@ -1012,6 +1045,17 @@ static int getlblockinc(Jpeg2000DecoderContext *s)
     return res;
 }
 
+static inline void select_header(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
+                                 int *tp_index)
+{
+    s->g = tile->tile_part[*tp_index].header_tpg;
+    if (bytestream2_get_bytes_left(&s->g) == 0 && s->bit_index == 8) {
+        if (*tp_index < FF_ARRAY_ELEMS(tile->tile_part) - 1) {
+            s->g = tile->tile_part[++(*tp_index)].tpg;
+        }
+    }
+}
+
 static inline void select_stream(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
                                  int *tp_index)
 {
@@ -1037,7 +1081,9 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
         return 0;
     rlevel->band[0].prec[precno].decoded_layers = layno + 1;
     // Select stream to read from
-    if (tile->has_ppt)
+    if (s->has_ppm)
+        select_header(s, tile, tp_index);
+    else if (tile->has_ppt)
         s->g = tile->packed_headers_stream;
     else
         select_stream(s, tile, tp_index);
@@ -1151,7 +1197,10 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
     }
 
     // Save state of stream
-    if (tile->has_ppt) {
+    if (s->has_ppm) {
+        tile->tile_part[*tp_index].header_tpg = s->g;
+        select_stream(s, tile, tp_index);
+    } else if (tile->has_ppt) {
         tile->packed_headers_stream = s->g;
         select_stream(s, tile, tp_index);
     }
@@ -1201,7 +1250,9 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
     return 0;
 
 skip_data:
-    if (tile->has_ppt)
+    if (s->has_ppm)
+        tile->tile_part[*tp_index].header_tpg = s->g;
+    else if (tile->has_ppt)
         tile->packed_headers_stream = s->g;
     else
         tile->tile_part[*tp_index].tpg = s->g;
@@ -2068,6 +2119,11 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
                 return AVERROR_INVALIDDATA;
             }
 
+            if (s->has_ppm) {
+                uint32_t tp_header_size = bytestream2_get_be32u(&s->packed_headers_stream);
+                bytestream2_init(&tp->header_tpg, s->packed_headers_stream.buffer, tp_header_size);
+                bytestream2_skip(&s->packed_headers_stream, tp_header_size);
+            }
             if (tile->has_ppt && tile->tp_idx == 0) {
                 bytestream2_init(&tile->packed_headers_stream, tile->packed_headers, tile->packed_headers_size);
             }
@@ -2119,6 +2175,12 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
             ret = get_poc(s, len, poc);
             break;
         case JPEG2000_SOT:
+            if (!s->in_tile_headers) {
+                s->in_tile_headers = 1;
+                if (s->has_ppm) {
+                    bytestream2_init(&s->packed_headers_stream, s->packed_headers, s->packed_headers_size);
+                }
+            }
             if (!(ret = get_sot(s, len))) {
                 av_assert1(s->curtileno >= 0);
                 codsty = s->tile[s->curtileno].codsty;
@@ -2144,8 +2206,18 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
             // Packet length, tile-part header
             ret = get_plt(s, len);
             break;
+        case JPEG2000_PPM:
+            // Packed headers, main header
+            ret = get_ppm(s, len);
+            break;
         case JPEG2000_PPT:
             // Packed headers, tile-part header
+            if (s->has_ppm) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "Cannot have both PPT and PPM marker.\n");
+                return AVERROR_INVALIDDATA;
+            }
+
             ret = get_ppt(s, len);
             break;
         default:
-- 
2.17.1