Add support for the ffmpeg/vapoursynth high bit depth y4m extensions

input/y4m.c

@@ -35,6 +35,7 @@ typedef struct
     int frame_header_len;
     uint64_t frame_size;
     uint64_t plane_size[3];
+    int bit_depth;
 } y4m_hnd_t;
 
 #define Y4M_MAGIC "YUV4MPEG2"
@@ -42,15 +43,23 @@ typedef struct
 #define Y4M_FRAME_MAGIC "FRAME"
 #define MAX_FRAME_HEADER 80
 
-static int csp_string_to_int( char *csp_name )
+static int parse_csp_and_depth( char *csp_name, int *bit_depth )
 {
-    int csp = X264_CSP_MAX;
+    int csp    = X264_CSP_MAX;
+    *bit_depth = 8;
+
+    /* Set colorspace from known variants */
     if( !strncmp( "420", csp_name, 3 ) )
         csp = X264_CSP_I420;
     else if( !strncmp( "422", csp_name, 3 ) )
         csp = X264_CSP_I422;
     else if( !strncmp( "444", csp_name, 3 ) && strncmp( "444alpha", csp_name, 8 ) ) // only accept alphaless 4:4:4
         csp = X264_CSP_I444;
+
+    /* Set high bit depth from known extensions */
+    if( !strncmp( "p", csp_name + 3, 1 ) )
+        *bit_depth = strtol( csp_name + 4, NULL, 10 );
+
     return csp;
 }
 
@@ -63,6 +72,7 @@ static int open_file( char *psz_filename, hnd_t *p_handle, video_info_t *info, c
     char *tokend, *header_end;
     int colorspace = X264_CSP_NONE;
     int alt_colorspace = X264_CSP_NONE;
+    int alt_bit_depth  = 8;
     if( !h )
         return -1;
 
@@ -112,7 +122,7 @@ static int open_file( char *psz_filename, hnd_t *p_handle, video_info_t *info, c
                 tokstart=tokend;
                 break;
             case 'C': /* Color space */
-                colorspace = csp_string_to_int( tokstart );
+                colorspace = parse_csp_and_depth( tokstart, &h->bit_depth );
                 tokstart = strchr( tokstart, 0x20 );
                 break;
             case 'I': /* Interlace type */
@@ -159,7 +169,7 @@ static int open_file( char *psz_filename, hnd_t *p_handle, video_info_t *info, c
                 {
                     /* Older nonstandard pixel format representation */
                     tokstart += 6;
-                    alt_colorspace = csp_string_to_int( tokstart );
+                    alt_colorspace = parse_csp_and_depth( tokstart, &alt_bit_depth );
                 }
                 tokstart = strchr( tokstart, 0x20 );
                 break;
@@ -167,22 +177,37 @@ static int open_file( char *psz_filename, hnd_t *p_handle, video_info_t *info, c
     }
 
     if( colorspace == X264_CSP_NONE )
-        colorspace = alt_colorspace;
+    {
+        colorspace   = alt_colorspace;
+        h->bit_depth = alt_bit_depth;
+    }
 
-    // default to 4:2:0 if nothing is specified
+    // default to 8bit 4:2:0 if nothing is specified
     if( colorspace == X264_CSP_NONE )
-        colorspace = X264_CSP_I420;
+    {
+        colorspace    = X264_CSP_I420;
+        h->bit_depth  = 8;
+    }
 
     FAIL_IF_ERROR( colorspace <= X264_CSP_NONE || colorspace >= X264_CSP_MAX, "colorspace unhandled\n" )
+    FAIL_IF_ERROR( h->bit_depth < 8 || h->bit_depth > 16, "unsupported bit depth `%d'\n", h->bit_depth );
 
     info->thread_safe = 1;
     info->num_frames  = 0;
     info->csp         = colorspace;
     h->frame_size     = h->frame_header_len;
-    for( i = 0; i < x264_cli_csps[info->csp].planes; i++ )
+
+    if( h->bit_depth > 8 )
+        info->csp |= X264_CSP_HIGH_DEPTH;
+
+    const x264_cli_csp_t *csp = x264_cli_get_csp( info->csp );
+
+    for( i = 0; i < csp->planes; i++ )
     {
         h->plane_size[i] = x264_cli_pic_plane_size( info->csp, info->width, info->height, i );
         h->frame_size += h->plane_size[i];
+        /* x264_cli_pic_plane_size returns the size in bytes, we need the value in pixels from here on */
+        h->plane_size[i] /= x264_cli_csp_depth_factor( info->csp );
     }
 
     /* Most common case: frame_header = "FRAME" */
@@ -202,6 +227,7 @@ static int open_file( char *psz_filename, hnd_t *p_handle, video_info_t *info, c
 static int read_frame_internal( cli_pic_t *pic, y4m_hnd_t *h )
 {
     size_t slen = strlen( Y4M_FRAME_MAGIC );
+    int pixel_depth = x264_cli_csp_depth_factor( pic->img.csp );
     int i = 0;
     char header[16];
 
@@ -222,7 +248,19 @@ static int read_frame_internal( cli_pic_t *pic, y4m_hnd_t *h )
 
     int error = 0;
     for( i = 0; i < pic->img.planes && !error; i++ )
-        error |= fread( pic->img.plane[i], h->plane_size[i], 1, h->fh ) <= 0;
+    {
+        error |= fread( pic->img.plane[i], pixel_depth, h->plane_size[i], h->fh ) != h->plane_size[i];
+        if( h->bit_depth & 7 )
+        {
+            /* upconvert non 16bit high depth planes to 16bit using the same
+             * algorithm as used in the depth filter. */
+            uint16_t *plane = (uint16_t*)pic->img.plane[i];
+            uint64_t pixel_count = h->plane_size[i];
+            int lshift = 16 - h->bit_depth;
+            for( uint64_t j = 0; j < pixel_count; j++ )
+                plane[j] = plane[j] << lshift;
+        }
+    }
     return error;
 }