sgi: encode images with 4 channels at 8 and 16 bits

Changelog

@@ -11,7 +11,7 @@ version <next>:
 - XBM decoder
 - bmp standalone parser
 - OpenEXR image decoder
-- support decoding 4-channel SGI images
+- support encoding and decoding 4-channel SGI images
 
 
 version 10:

libavcodec/sgienc.c

@@ -50,6 +50,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     uint8_t *offsettab, *lengthtab, *in_buf, *encode_buf, *buf;
     int x, y, z, length, tablesize, ret;
     unsigned int width, height, depth, dimension;
+    unsigned int bytes_per_channel, pixmax, put_be;
     unsigned char *end_buf;
 
     avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
@@ -57,6 +58,9 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 
     width  = avctx->width;
     height = avctx->height;
+    bytes_per_channel = 1;
+    pixmax = 0xFF;
+    put_be = HAVE_BIGENDIAN;
 
     switch (avctx->pix_fmt) {
     case AV_PIX_FMT_GRAY8:
@@ -71,6 +75,33 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
         dimension = SGI_MULTI_CHAN;
         depth     = SGI_RGBA;
         break;
+    case AV_PIX_FMT_GRAY16LE:
+        put_be = !HAVE_BIGENDIAN;
+    case AV_PIX_FMT_GRAY16BE:
+        avctx->coder_type = FF_CODER_TYPE_RAW;
+        bytes_per_channel = 2;
+        pixmax = 0xFFFF;
+        dimension = SGI_SINGLE_CHAN;
+        depth     = SGI_GRAYSCALE;
+        break;
+    case AV_PIX_FMT_RGB48LE:
+        put_be = !HAVE_BIGENDIAN;
+    case AV_PIX_FMT_RGB48BE:
+        avctx->coder_type = FF_CODER_TYPE_RAW;
+        bytes_per_channel = 2;
+        pixmax = 0xFFFF;
+        dimension = SGI_MULTI_CHAN;
+        depth     = SGI_RGB;
+        break;
+    case AV_PIX_FMT_RGBA64LE:
+        put_be = !HAVE_BIGENDIAN;
+    case AV_PIX_FMT_RGBA64BE:
+        avctx->coder_type = FF_CODER_TYPE_RAW;
+        bytes_per_channel = 2;
+        pixmax = 0xFFFF;
+        dimension = SGI_MULTI_CHAN;
+        depth     = SGI_RGBA;
+        break;
     default:
         return AVERROR_INVALIDDATA;
     }
@@ -82,7 +113,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     else // assume ff_rl_encode() produces at most 2x size of input
         length += tablesize * 2 + depth * height * (2 * width + 1);
 
-    if ((ret = ff_alloc_packet(pkt, length)) < 0) {
+    if ((ret = ff_alloc_packet(pkt, bytes_per_channel * length)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
         return ret;
     }
@@ -92,15 +123,14 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     /* Encode header. */
     bytestream_put_be16(&buf, SGI_MAGIC);
     bytestream_put_byte(&buf, avctx->coder_type != FF_CODER_TYPE_RAW); /* RLE 1 - VERBATIM 0*/
-    bytestream_put_byte(&buf, 1); /* bytes_per_channel */
+    bytestream_put_byte(&buf, bytes_per_channel);
     bytestream_put_be16(&buf, dimension);
     bytestream_put_be16(&buf, width);
     bytestream_put_be16(&buf, height);
     bytestream_put_be16(&buf, depth);
 
-    /* The rest are constant in this implementation. */
     bytestream_put_be32(&buf, 0L); /* pixmin */
-    bytestream_put_be32(&buf, 255L); /* pixmax */
+    bytestream_put_be32(&buf, pixmax);
     bytestream_put_be32(&buf, 0L); /* dummy */
 
     /* name */
@@ -150,11 +180,17 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
         av_free(encode_buf);
     } else {
         for (z = 0; z < depth; z++) {
-            in_buf = p->data[0] + p->linesize[0] * (height - 1) + z;
+            in_buf = p->data[0] + p->linesize[0] * (height - 1) + z * bytes_per_channel;
 
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width * depth; x += depth)
-                    bytestream_put_byte(&buf, in_buf[x]);
+                    if (bytes_per_channel == 1)
+                        bytestream_put_byte(&buf, in_buf[x]);
+                    else
+                        if (put_be)
+                            bytestream_put_be16(&buf, ((uint16_t *)in_buf)[x]);
+                        else
+                            bytestream_put_le16(&buf, ((uint16_t *)in_buf)[x]);
 
                 in_buf -= p->linesize[0];
             }
@@ -184,6 +220,10 @@ AVCodec ff_sgi_encoder = {
     .encode2   = encode_frame,
     .close     = encode_close,
     .pix_fmts  = (const enum AVPixelFormat[]) {
-        AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
+        AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
+        AV_PIX_FMT_RGB48LE, AV_PIX_FMT_RGB48BE,
+        AV_PIX_FMT_RGBA64LE, AV_PIX_FMT_RGBA64BE,
+        AV_PIX_FMT_GRAY16LE, AV_PIX_FMT_GRAY16BE, AV_PIX_FMT_GRAY8,
+        AV_PIX_FMT_NONE
     },
 };