Interplay MVE: Implement frame format 0x10

This implements the 0x10 frame format for Interplay MVE movies. The
format is a variation on the 0x06 format with some changes. In addition
to the decoding map there's also a skip map. This skip map is used to
determine what 8x8 blocks can change in a particular frame.

This format expects to be able to copy an 8x8 block from before the last
time it was changed. This can be an arbitrary time in the past. In order
to implement this this decoder allocates two additional AVFrames where
actual decoding happens. At the end of a frame decoding changed blocks
are copied to a finished frame based on the skip map.

The skip map's encoding is a little convulted, I'll refer to the code
for details.

Values in the decoding map are the same as in format 0x06.

Signed-off-by: Hein-Pieter van Braam <hp@tmm.cx>

1 files changed, 175 insertions, 7 deletions

diff --git a/libavcodec/interplayvideo.c b/libavcodec/interplayvideo.c
index 431eeb12c7..421de26cb1 100644
--- a/libavcodec/interplayvideo.c
+++ b/libavcodec/interplayvideo.c
@@ -55,8 +55,15 @@ typedef struct IpvideoContext {
     HpelDSPContext hdsp;
     AVFrame *second_last_frame;
     AVFrame *last_frame;
+
+    /* For format 0x10 */
+    AVFrame *cur_decode_frame;
+    AVFrame *prev_decode_frame;
+
     const unsigned char *decoding_map;
     int decoding_map_size;
+    const unsigned char *skip_map;
+    int skip_map_size;
 
     int is_16bpp;
     GetByteContext stream_ptr, mv_ptr;
@@ -977,6 +984,114 @@ static void ipvideo_decode_format_06_opcodes(IpvideoContext *s, AVFrame *frame)
     }
 }
 
+static void ipvideo_format_10_firstpass(IpvideoContext *s, AVFrame *frame, short opcode)
+{
+    int line;
+
+    if (!opcode) {
+        for (line = 0; line < 8; ++line) {
+            bytestream2_get_buffer(&s->stream_ptr, s->pixel_ptr, 8);
+            s->pixel_ptr += s->stride;
+        }
+    }
+}
+
+static void ipvideo_format_10_secondpass(IpvideoContext *s, AVFrame *frame, short opcode)
+{
+    int off_x, off_y;
+
+    if (opcode < 0) {
+        off_x = ((unsigned short)opcode - 0xC000) % s->cur_decode_frame->linesize[0];
+        off_y = ((unsigned short)opcode - 0xC000) / s->cur_decode_frame->linesize[0];
+        copy_from(s, s->prev_decode_frame, s->cur_decode_frame, off_x, off_y);
+    } else if (opcode > 0) {
+        off_x = ((unsigned short)opcode - 0x4000) % s->cur_decode_frame->linesize[0];
+        off_y = ((unsigned short)opcode - 0x4000) / s->cur_decode_frame->linesize[0];
+        copy_from(s, s->cur_decode_frame, s->cur_decode_frame, off_x, off_y);
+    }
+}
+
+static void (* const ipvideo_format_10_passes[])(IpvideoContext *s, AVFrame *frame, short op) = {
+    ipvideo_format_10_firstpass, ipvideo_format_10_secondpass,
+};
+
+static void ipvideo_decode_format_10_opcodes(IpvideoContext *s, AVFrame *frame)
+{
+    int pass, x, y, changed_block;
+    short opcode, skip;
+    GetByteContext decoding_map_ptr;
+    GetByteContext skip_map_ptr;
+
+    bytestream2_skip(&s->stream_ptr, 14); /* data starts 14 bytes in */
+
+    /* this is PAL8, so make the palette available */
+    memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
+    s->stride = frame->linesize[0];
+
+    s->line_inc = s->stride - 8;
+    s->upper_motion_limit_offset = (s->avctx->height - 8) * frame->linesize[0]
+                                  + (s->avctx->width - 8) * (1 + s->is_16bpp);
+
+    bytestream2_init(&decoding_map_ptr, s->decoding_map, s->decoding_map_size);
+    bytestream2_init(&skip_map_ptr, s->skip_map, s->skip_map_size);
+
+    for (pass = 0; pass < 2; ++pass) {
+        bytestream2_seek(&decoding_map_ptr, 0, SEEK_SET);
+        bytestream2_seek(&skip_map_ptr, 0, SEEK_SET);
+        skip = bytestream2_get_le16(&skip_map_ptr);
+
+        for (y = 0; y < s->avctx->height; y += 8) {
+            for (x = 0; x < s->avctx->width; x += 8) {
+                s->pixel_ptr = s->cur_decode_frame->data[0] + x + y * s->cur_decode_frame->linesize[0];
+
+                while (skip <= 0)  {
+                    if (skip != -0x8000 && skip) {
+                        opcode = bytestream2_get_le16(&decoding_map_ptr);
+                        ipvideo_format_10_passes[pass](s, frame, opcode);
+                        break;
+                    }
+                    skip = bytestream2_get_le16(&skip_map_ptr);
+                }
+                skip *= 2;
+            }
+        }
+    }
+
+    bytestream2_seek(&skip_map_ptr, 0, SEEK_SET);
+    skip = bytestream2_get_le16(&skip_map_ptr);
+    for (y = 0; y < s->avctx->height; y += 8) {
+        for (x = 0; x < s->avctx->width; x += 8) {
+            changed_block = 0;
+            s->pixel_ptr = frame->data[0] + x + y*frame->linesize[0];
+
+            while (skip <= 0)  {
+                if (skip != -0x8000 && skip) {
+                    changed_block = 1;
+                    break;
+                }
+                skip = bytestream2_get_le16(&skip_map_ptr);
+            }
+
+            if (changed_block) {
+                copy_from(s, s->cur_decode_frame, frame, 0, 0);
+            } else {
+                /* Don't try to copy last_frame data on the first frame */
+                if (s->avctx->frame_number)
+                    copy_from(s, s->last_frame, frame, 0, 0);
+            }
+            skip *= 2;
+        }
+    }
+
+    FFSWAP(AVFrame*, s->prev_decode_frame, s->cur_decode_frame);
+
+    if (bytestream2_get_bytes_left(&s->stream_ptr) > 1) {
+        av_log(s->avctx, AV_LOG_DEBUG,
+               "decode finished with %d bytes left over\n",
+               bytestream2_get_bytes_left(&s->stream_ptr));
+    }
+}
+
 static void ipvideo_decode_format_11_opcodes(IpvideoContext *s, AVFrame *frame)
 {
     int x, y;
@@ -1046,12 +1161,27 @@ static av_cold int ipvideo_decode_init(AVCodecContext *avctx)
 
     s->last_frame        = av_frame_alloc();
     s->second_last_frame = av_frame_alloc();
-    if (!s->last_frame || !s->second_last_frame) {
+    s->cur_decode_frame  = av_frame_alloc();
+    s->prev_decode_frame = av_frame_alloc();
+    if (!s->last_frame || !s->second_last_frame ||
+        !s->cur_decode_frame || !s->prev_decode_frame) {
         av_frame_free(&s->last_frame);
         av_frame_free(&s->second_last_frame);
+        av_frame_free(&s->cur_decode_frame);
+        av_frame_free(&s->prev_decode_frame);
         return AVERROR(ENOMEM);
     }
 
+    s->cur_decode_frame->width   = avctx->width;
+    s->prev_decode_frame->width  = avctx->width;
+    s->cur_decode_frame->height  = avctx->height;
+    s->prev_decode_frame->height = avctx->height;
+    s->cur_decode_frame->format  = avctx->pix_fmt;
+    s->prev_decode_frame->format = avctx->pix_fmt;
+
+    ff_get_buffer(avctx, s->cur_decode_frame, 0);
+    ff_get_buffer(avctx, s->prev_decode_frame, 0);
+
     return 0;
 }
 
@@ -1073,13 +1203,14 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
         av_frame_unref(s->second_last_frame);
     }
 
-    if (buf_size < 6)
+    if (buf_size < 8)
         return AVERROR_INVALIDDATA;
 
     frame_format         = AV_RL8(buf);
     send_buffer          = AV_RL8(buf + 1);
     video_data_size      = AV_RL16(buf + 2);
     s->decoding_map_size = AV_RL16(buf + 4);
+    s->skip_map_size     = AV_RL16(buf + 6);
 
     switch(frame_format) {
         case 0x06:
@@ -1088,6 +1219,11 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
                 return AVERROR_INVALIDDATA;
             }
 
+            if (s->skip_map_size) {
+                av_log(avctx, AV_LOG_ERROR, "Skip map for format 0x06\n");
+                return AVERROR_INVALIDDATA;
+            }
+
             if (s->is_16bpp) {
                 av_log(avctx, AV_LOG_ERROR, "Video format 0x06 does not support 16bpp movies\n");
                 return AVERROR_INVALIDDATA;
@@ -1095,9 +1231,31 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
 
             /* Decoding map for 0x06 frame format is at the top of pixeldata */
             s->decoding_map_size = ((s->avctx->width / 8) * (s->avctx->height / 8)) * 2;
-            s->decoding_map = buf + 6 + 14; /* 14 bits of op data */
+            s->decoding_map = buf + 8 + 14; /* 14 bits of op data */
             video_data_size -= s->decoding_map_size + 14;
-            bytestream2_init(&s->stream_ptr, buf + 6 + s->decoding_map_size + 14, video_data_size);
+            bytestream2_init(&s->stream_ptr, buf + 8 + s->decoding_map_size + 14, video_data_size);
+
+            break;
+
+        case 0x10:
+            if (! s->decoding_map_size) {
+                av_log(avctx, AV_LOG_ERROR, "Empty decoding map for format 0x10\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            if (! s->skip_map_size) {
+                av_log(avctx, AV_LOG_ERROR, "Empty skip map for format 0x10\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            if (s->is_16bpp) {
+                av_log(avctx, AV_LOG_ERROR, "Video format 0x10 does not support 16bpp movies\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            bytestream2_init(&s->stream_ptr, buf + 8, video_data_size);
+            s->decoding_map = buf + 8 + video_data_size;
+            s->skip_map = buf + 8 + video_data_size + s->decoding_map_size;
 
             break;
 
@@ -1107,8 +1265,13 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
                 return AVERROR_INVALIDDATA;
             }
 
-            bytestream2_init(&s->stream_ptr, buf + 6, video_data_size);
-            s->decoding_map = buf + 6 + video_data_size;
+            if (s->skip_map_size) {
+                av_log(avctx, AV_LOG_ERROR, "Skip map for format 0x11\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            bytestream2_init(&s->stream_ptr, buf + 8, video_data_size);
+            s->decoding_map = buf + 8 + video_data_size;
 
             break;
 
@@ -1117,7 +1280,7 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
     }
 
     /* ensure we can't overread the packet */
-    if (buf_size < 6 + s->decoding_map_size + video_data_size) {
+    if (buf_size < 8 + s->decoding_map_size + video_data_size + s->skip_map_size) {
         av_log(avctx, AV_LOG_ERROR, "Invalid IP packet size\n");
         return AVERROR_INVALIDDATA;
     }
@@ -1140,6 +1303,9 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
         case 0x06:
             ipvideo_decode_format_06_opcodes(s, frame);
             break;
+        case 0x10:
+            ipvideo_decode_format_10_opcodes(s, frame);
+            break;
         case 0x11:
             ipvideo_decode_format_11_opcodes(s, frame);
             break;
@@ -1163,6 +1329,8 @@ static av_cold int ipvideo_decode_end(AVCodecContext *avctx)
 
     av_frame_free(&s->last_frame);
     av_frame_free(&s->second_last_frame);
+    av_frame_free(&s->cur_decode_frame);
+    av_frame_free(&s->prev_decode_frame);
 
     return 0;
 }