1 files changed, 294 insertions, 130 deletions

diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
index 4f175a347f..1cafd9f832 100644
--- a/libavcodec/pgssubdec.c
+++ b/libavcodec/pgssubdec.c
@@ -33,38 +33,104 @@
 #include "libavutil/imgutils.h"
 
 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
+#define MAX_EPOCH_PALETTES 8   // Max 8 allowed per PGS epoch
+#define MAX_EPOCH_OBJECTS  64  // Max 64 allowed per PGS epoch
+#define MAX_OBJECT_REFS    2   // Max objects per display set
 
 enum SegmentType {
     PALETTE_SEGMENT      = 0x14,
-    PICTURE_SEGMENT      = 0x15,
+    OBJECT_SEGMENT       = 0x15,
     PRESENTATION_SEGMENT = 0x16,
     WINDOW_SEGMENT       = 0x17,
     DISPLAY_SEGMENT      = 0x80,
 };
 
+typedef struct PGSSubObjectRef {
+    int     id;
+    int     window_id;
+    uint8_t composition_flag;
+    int     x;
+    int     y;
+    int     crop_x;
+    int     crop_y;
+    int     crop_w;
+    int     crop_h;
+} PGSSubObjectRef;
+
 typedef struct PGSSubPresentation {
-    int x;
-    int y;
     int id_number;
-    int object_number;
-    uint8_t composition_flag;
+    int palette_id;
+    int object_count;
+    PGSSubObjectRef objects[MAX_OBJECT_REFS];
     int64_t pts;
 } PGSSubPresentation;
 
-typedef struct PGSSubPicture {
+typedef struct PGSSubObject {
+    int          id;
     int          w;
     int          h;
     uint8_t      *rle;
     unsigned int rle_buffer_size, rle_data_len;
     unsigned int rle_remaining_len;
-} PGSSubPicture;
+} PGSSubObject;
+
+typedef struct PGSSubObjects {
+    int          count;
+    PGSSubObject object[MAX_EPOCH_OBJECTS];
+} PGSSubObjects;
+
+typedef struct PGSSubPalette {
+    int         id;
+    uint32_t    clut[256];
+} PGSSubPalette;
+
+typedef struct PGSSubPalettes {
+    int           count;
+    PGSSubPalette palette[MAX_EPOCH_PALETTES];
+} PGSSubPalettes;
 
 typedef struct PGSSubContext {
     PGSSubPresentation presentation;
-    uint32_t           clut[256];
-    PGSSubPicture      picture;
+    PGSSubPalettes     palettes;
+    PGSSubObjects      objects;
 } PGSSubContext;
 
+static void flush_cache(AVCodecContext *avctx)
+{
+    PGSSubContext *ctx = avctx->priv_data;
+    int i;
+
+    for (i = 0; i < ctx->objects.count; i++) {
+        av_freep(&ctx->objects.object[i].rle);
+        ctx->objects.object[i].rle_buffer_size  = 0;
+        ctx->objects.object[i].rle_remaining_len  = 0;
+    }
+    ctx->objects.count = 0;
+    ctx->palettes.count = 0;
+}
+
+static PGSSubObject * find_object(int id, PGSSubObjects *objects)
+{
+    int i;
+
+    for (i = 0; i < objects->count; i++) {
+        if (objects->object[i].id == id)
+            return &objects->object[i];
+    }
+    return NULL;
+}
+
+static PGSSubPalette * find_palette(int id, PGSSubPalettes *palettes)
+{
+    int i;
+
+    for (i = 0; i < palettes->count; i++) {
+        if (palettes->palette[i].id == id)
+            return &palettes->palette[i];
+    }
+    return NULL;
+}
+
 static av_cold int init_decoder(AVCodecContext *avctx)
 {
     avctx->pix_fmt = AV_PIX_FMT_PAL8;
@@ -74,10 +140,7 @@ static av_cold int init_decoder(AVCodecContext *avctx)
 
 static av_cold int close_decoder(AVCodecContext *avctx)
 {
-    PGSSubContext *ctx = avctx->priv_data;
-
-    av_freep(&ctx->picture.rle);
-    ctx->picture.rle_buffer_size  = 0;
+    flush_cache(avctx);
 
     return 0;
 }
@@ -92,7 +155,7 @@ static av_cold int close_decoder(AVCodecContext *avctx)
  * @param buf pointer to the RLE data to process
  * @param buf_size size of the RLE data to process
  */
-static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub,
+static int decode_rle(AVCodecContext *avctx, AVSubtitleRect *rect,
                       const uint8_t *buf, unsigned int buf_size)
 {
     const uint8_t *rle_bitmap_end;
@@ -100,15 +163,15 @@ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub,
 
     rle_bitmap_end = buf + buf_size;
 
-    sub->rects[0]->pict.data[0] = av_malloc(sub->rects[0]->w * sub->rects[0]->h);
+    rect->pict.data[0] = av_malloc(rect->w * rect->h);
 
-    if (!sub->rects[0]->pict.data[0])
-        return -1;
+    if (!rect->pict.data[0])
+        return AVERROR(ENOMEM);
 
     pixel_count = 0;
     line_count  = 0;
 
-    while (buf < rle_bitmap_end && line_count < sub->rects[0]->h) {
+    while (buf < rle_bitmap_end && line_count < rect->h) {
         uint8_t flags, color;
         int run;
 
@@ -123,27 +186,31 @@ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub,
             color = flags & 0x80 ? bytestream_get_byte(&buf) : 0;
         }
 
-        if (run > 0 && pixel_count + run <= sub->rects[0]->w * sub->rects[0]->h) {
-            memset(sub->rects[0]->pict.data[0] + pixel_count, color, run);
+        if (run > 0 && pixel_count + run <= rect->w * rect->h) {
+            memset(rect->pict.data[0] + pixel_count, color, run);
             pixel_count += run;
         } else if (!run) {
             /*
              * New Line. Check if correct pixels decoded, if not display warning
              * and adjust bitmap pointer to correct new line position.
              */
-            if (pixel_count % sub->rects[0]->w > 0)
+            if (pixel_count % rect->w > 0) {
                 av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n",
-                       pixel_count % sub->rects[0]->w, sub->rects[0]->w);
+                       pixel_count % rect->w, rect->w);
+                if (avctx->err_recognition & AV_EF_EXPLODE) {
+                    return AVERROR_INVALIDDATA;
+                }
+            }
             line_count++;
         }
     }
 
-    if (pixel_count < sub->rects[0]->w * sub->rects[0]->h) {
+    if (pixel_count < rect->w * rect->h) {
         av_log(avctx, AV_LOG_ERROR, "Insufficient RLE data for subtitle\n");
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
 
-    av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[0]->w * sub->rects[0]->h);
+    av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, rect->w * rect->h);
 
     return 0;
 }
@@ -157,40 +224,52 @@ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub,
  * @param avctx contains the current codec context
  * @param buf pointer to the packet to process
  * @param buf_size size of packet to process
- * @todo TODO: Enable support for RLE data over multiple packets
  */
-static int parse_picture_segment(AVCodecContext *avctx,
+static int parse_object_segment(AVCodecContext *avctx,
                                   const uint8_t *buf, int buf_size)
 {
     PGSSubContext *ctx = avctx->priv_data;
+    PGSSubObject *object;
 
     uint8_t sequence_desc;
     unsigned int rle_bitmap_len, width, height;
+    int id;
 
     if (buf_size <= 4)
-        return -1;
+        return AVERROR_INVALIDDATA;
     buf_size -= 4;
 
-    /* skip 3 unknown bytes: Object ID (2 bytes), Version Number */
-    buf += 3;
+    id = bytestream_get_be16(&buf);
+    object = find_object(id, &ctx->objects);
+    if (!object) {
+        if (ctx->objects.count >= MAX_EPOCH_OBJECTS) {
+            av_log(avctx, AV_LOG_ERROR, "Too many objects in epoch\n");
+            return AVERROR_INVALIDDATA;
+        }
+        object = &ctx->objects.object[ctx->objects.count++];
+        object->id = id;
+    }
+
+    /* skip object version number */
+    buf += 1;
 
     /* Read the Sequence Description to determine if start of RLE data or appended to previous RLE */
     sequence_desc = bytestream_get_byte(&buf);
 
     if (!(sequence_desc & 0x80)) {
         /* Additional RLE data */
-        if (buf_size > ctx->picture.rle_remaining_len)
-            return -1;
+        if (buf_size > object->rle_remaining_len)
+            return AVERROR_INVALIDDATA;
 
-        memcpy(ctx->picture.rle + ctx->picture.rle_data_len, buf, buf_size);
-        ctx->picture.rle_data_len += buf_size;
-        ctx->picture.rle_remaining_len -= buf_size;
+        memcpy(object->rle + object->rle_data_len, buf, buf_size);
+        object->rle_data_len += buf_size;
+        object->rle_remaining_len -= buf_size;
 
         return 0;
     }
 
     if (buf_size <= 7)
-        return -1;
+        return AVERROR_INVALIDDATA;
     buf_size -= 7;
 
     /* Decode rle bitmap length, stored size includes width/height data */
@@ -203,20 +282,20 @@ static int parse_picture_segment(AVCodecContext *avctx,
     /* Make sure the bitmap is not too large */
     if (avctx->width < width || avctx->height < height) {
         av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger than video.\n");
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
 
-    ctx->picture.w = width;
-    ctx->picture.h = height;
+    object->w = width;
+    object->h = height;
 
-    av_fast_malloc(&ctx->picture.rle, &ctx->picture.rle_buffer_size, rle_bitmap_len);
+    av_fast_malloc(&object->rle, &object->rle_buffer_size, rle_bitmap_len);
 
-    if (!ctx->picture.rle)
-        return -1;
+    if (!object->rle)
+        return AVERROR(ENOMEM);
 
-    memcpy(ctx->picture.rle, buf, buf_size);
-    ctx->picture.rle_data_len = buf_size;
-    ctx->picture.rle_remaining_len = rle_bitmap_len - buf_size;
+    memcpy(object->rle, buf, buf_size);
+    object->rle_data_len = buf_size;
+    object->rle_remaining_len = rle_bitmap_len - buf_size;
 
     return 0;
 }
@@ -231,19 +310,32 @@ static int parse_picture_segment(AVCodecContext *avctx,
  * @param buf pointer to the packet to process
  * @param buf_size size of packet to process
  */
-static void parse_palette_segment(AVCodecContext *avctx,
+static int parse_palette_segment(AVCodecContext *avctx,
                                   const uint8_t *buf, int buf_size)
 {
     PGSSubContext *ctx = avctx->priv_data;
+    PGSSubPalette *palette;
 
     const uint8_t *buf_end = buf + buf_size;
     const uint8_t *cm      = ff_crop_tab + MAX_NEG_CROP;
     int color_id;
     int y, cb, cr, alpha;
     int r, g, b, r_add, g_add, b_add;
+    int id;
+
+    id  = bytestream_get_byte(&buf);
+    palette = find_palette(id, &ctx->palettes);
+    if (!palette) {
+        if (ctx->palettes.count >= MAX_EPOCH_PALETTES) {
+            av_log(avctx, AV_LOG_ERROR, "Too many palettes in epoch\n");
+            return AVERROR_INVALIDDATA;
+        }
+        palette = &ctx->palettes.palette[ctx->palettes.count++];
+        palette->id  = id;
+    }
 
-    /* Skip two null bytes */
-    buf += 2;
+    /* Skip palette version */
+    buf += 1;
 
     while (buf < buf_end) {
         color_id  = bytestream_get_byte(&buf);
@@ -258,8 +350,9 @@ static void parse_palette_segment(AVCodecContext *avctx,
         av_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha);
 
         /* Store color in palette */
-        ctx->clut[color_id] = RGBA(r,g,b,alpha);
+        palette->clut[color_id] = RGBA(r,g,b,alpha);
     }
+    return 0;
 }
 
 /**
@@ -272,7 +365,6 @@ static void parse_palette_segment(AVCodecContext *avctx,
  * @param buf pointer to the packet to process
  * @param buf_size size of packet to process
  * @todo TODO: Implement cropping
- * @todo TODO: Implement forcing of subtitles
  */
 static int parse_presentation_segment(AVCodecContext *avctx,
                                       const uint8_t *buf, int buf_size,
@@ -280,8 +372,9 @@ static int parse_presentation_segment(AVCodecContext *avctx,
 {
     PGSSubContext *ctx = avctx->priv_data;
 
-    int x, y, ret;
+    int i, state, ret;
 
+    // Video descriptor
     int w = bytestream_get_be16(&buf);
     int h = bytestream_get_be16(&buf);
 
@@ -293,49 +386,75 @@ static int parse_presentation_segment(AVCodecContext *avctx,
     if (ret < 0)
         return ret;
 
-    /* Skip 1 bytes of unknown, frame rate? */
+    /* Skip 1 bytes of unknown, frame rate */
     buf++;
 
+    // Composition descriptor
     ctx->presentation.id_number = bytestream_get_be16(&buf);
-
     /*
-     * Skip 3 bytes of unknown:
-     *     state
-     *     palette_update_flag (0x80),
-     *     palette_id_to_use,
+     * state is a 2 bit field that defines pgs epoch boundaries
+     * 00 - Normal, previously defined objects and palettes are still valid
+     * 01 - Acquisition point, previous objects and palettes can be released
+     * 10 - Epoch start, previous objects and palettes can be released
+     * 11 - Epoch continue, previous objects and palettes can be released
+     *
+     * reserved 6 bits discarded
      */
-    buf += 3;
-
-    ctx->presentation.object_number = bytestream_get_byte(&buf);
-    ctx->presentation.composition_flag = 0;
-    if (!ctx->presentation.object_number)
-        return 0;
+    state = bytestream_get_byte(&buf) >> 6;
+    if (state != 0) {
+        flush_cache(avctx);
+    }
 
     /*
-     * Skip 3 bytes of unknown:
-     *     object_id_ref (2 bytes),
-     *     window_id_ref,
+     * skip palette_update_flag (0x80),
      */
-    buf += 3;
-    ctx->presentation.composition_flag = bytestream_get_byte(&buf);
-
-    x = bytestream_get_be16(&buf);
-    y = bytestream_get_be16(&buf);
-
-    /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/
+    buf += 1;
+    ctx->presentation.palette_id = bytestream_get_byte(&buf);
+    ctx->presentation.object_count = bytestream_get_byte(&buf);
+    if (ctx->presentation.object_count > MAX_OBJECT_REFS) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Invalid number of presentation objects %d\n",
+               ctx->presentation.object_count);
+        ctx->presentation.object_count = 2;
+        if (avctx->err_recognition & AV_EF_EXPLODE) {
+            return AVERROR_INVALIDDATA;
+        }
+    }
 
-    av_dlog(avctx, "Subtitle Placement x=%d, y=%d\n", x, y);
+    for (i = 0; i < ctx->presentation.object_count; i++)
+    {
+        ctx->presentation.objects[i].id = bytestream_get_be16(&buf);
+        ctx->presentation.objects[i].window_id = bytestream_get_byte(&buf);
+        ctx->presentation.objects[i].composition_flag = bytestream_get_byte(&buf);
+
+        ctx->presentation.objects[i].x = bytestream_get_be16(&buf);
+        ctx->presentation.objects[i].y = bytestream_get_be16(&buf);
+
+        // If cropping
+        if (ctx->presentation.objects[i].composition_flag & 0x80) {
+            ctx->presentation.objects[i].crop_x = bytestream_get_be16(&buf);
+            ctx->presentation.objects[i].crop_y = bytestream_get_be16(&buf);
+            ctx->presentation.objects[i].crop_w = bytestream_get_be16(&buf);
+            ctx->presentation.objects[i].crop_h = bytestream_get_be16(&buf);
+        }
 
-    if (x > avctx->width || y > avctx->height) {
-        av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n",
-               x, y, avctx->width, avctx->height);
-        x = 0; y = 0;
+        av_dlog(avctx, "Subtitle Placement x=%d, y=%d\n",
+                ctx->presentation.objects[i].x, ctx->presentation.objects[i].y);
+
+        if (ctx->presentation.objects[i].x > avctx->width ||
+            ctx->presentation.objects[i].y > avctx->height) {
+            av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n",
+                   ctx->presentation.objects[i].x,
+                   ctx->presentation.objects[i].y,
+                    avctx->width, avctx->height);
+            ctx->presentation.objects[i].x = 0;
+            ctx->presentation.objects[i].y = 0;
+            if (avctx->err_recognition & AV_EF_EXPLODE) {
+                return AVERROR_INVALIDDATA;
+            }
+        }
     }
 
-    /* Fill in dimensions */
-    ctx->presentation.x = x;
-    ctx->presentation.y = y;
-
     return 0;
 }
 
@@ -348,64 +467,105 @@ static int parse_presentation_segment(AVCodecContext *avctx,
  * @param data pointer to the data pertaining the subtitle to display
  * @param buf pointer to the packet to process
  * @param buf_size size of packet to process
- * @todo TODO: Fix start time, relies on correct PTS, currently too late
- *
- * @todo TODO: Fix end time, normally cleared by a second display
- * @todo       segment, which is currently ignored as it clears
- * @todo       the subtitle too early.
  */
 static int display_end_segment(AVCodecContext *avctx, void *data,
                                const uint8_t *buf, int buf_size)
 {
     AVSubtitle    *sub = data;
     PGSSubContext *ctx = avctx->priv_data;
-
-    /*
-     *      The end display time is a timeout value and is only reached
-     *      if the next subtitle is later then timeout or subtitle has
-     *      not been cleared by a subsequent empty display command.
-     */
+    PGSSubPalette *palette;
+    int i, ret;
 
     memset(sub, 0, sizeof(*sub));
     sub->pts = ctx->presentation.pts;
-
-    // Blank if last object_number was 0.
-    // Note that this may be wrong for more complex subtitles.
-    if (!ctx->presentation.object_number)
-        return 1;
     sub->start_display_time = 0;
-    sub->end_display_time   = 20000;
+    // There is no explicit end time for PGS subtitles.  The end time
+    // is defined by the start of the next sub which may contain no
+    // objects (i.e. clears the previous sub)
+    sub->end_display_time   = UINT32_MAX;
     sub->format             = 0;
 
-    sub->rects     = av_mallocz(sizeof(*sub->rects));
-    sub->rects[0]  = av_mallocz(sizeof(*sub->rects[0]));
-    sub->num_rects = 1;
-
-    if (ctx->presentation.composition_flag & 0x40)
-        sub->rects[0]->flags |= AV_SUBTITLE_FLAG_FORCED;
+    // Blank if last object_count was 0.
+    if (!ctx->presentation.object_count)
+        return 1;
+    sub->rects = av_mallocz(sizeof(*sub->rects) * ctx->presentation.object_count);
+    if (!sub->rects) {
+        return AVERROR(ENOMEM);
+    }
+    palette = find_palette(ctx->presentation.palette_id, &ctx->palettes);
+    if (!palette) {
+        // Missing palette.  Should only happen with damaged streams.
+        av_log(avctx, AV_LOG_ERROR, "Invalid palette id %d\n",
+               ctx->presentation.palette_id);
+        avsubtitle_free(sub);
+        return AVERROR_INVALIDDATA;
+    }
+    for (i = 0; i < ctx->presentation.object_count; i++) {
+        PGSSubObject *object;
 
-    sub->rects[0]->x    = ctx->presentation.x;
-    sub->rects[0]->y    = ctx->presentation.y;
-    sub->rects[0]->w    = ctx->picture.w;
-    sub->rects[0]->h    = ctx->picture.h;
-    sub->rects[0]->type = SUBTITLE_BITMAP;
+        sub->rects[i]  = av_mallocz(sizeof(*sub->rects[0]));
+        if (!sub->rects[i]) {
+            avsubtitle_free(sub);
+            return AVERROR(ENOMEM);
+        }
+        sub->num_rects++;
+        sub->rects[i]->type = SUBTITLE_BITMAP;
+
+        /* Process bitmap */
+        object = find_object(ctx->presentation.objects[i].id, &ctx->objects);
+        if (!object) {
+            // Missing object.  Should only happen with damaged streams.
+            av_log(avctx, AV_LOG_ERROR, "Invalid object id %d\n",
+                   ctx->presentation.objects[i].id);
+            if (avctx->err_recognition & AV_EF_EXPLODE) {
+                avsubtitle_free(sub);
+                return AVERROR_INVALIDDATA;
+            }
+            // Leaves rect empty with 0 width and height.
+            continue;
+        }
+        if (ctx->presentation.objects[i].composition_flag & 0x40)
+            sub->rects[i]->flags |= AV_SUBTITLE_FLAG_FORCED;
+
+        sub->rects[i]->x    = ctx->presentation.objects[i].x;
+        sub->rects[i]->y    = ctx->presentation.objects[i].y;
+        sub->rects[i]->w    = object->w;
+        sub->rects[i]->h    = object->h;
+
+        sub->rects[i]->pict.linesize[0] = object->w;
+
+        if (object->rle) {
+            if (object->rle_remaining_len) {
+                av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n",
+                       object->rle_data_len, object->rle_remaining_len);
+                if (avctx->err_recognition & AV_EF_EXPLODE) {
+                    avsubtitle_free(sub);
+                    return AVERROR_INVALIDDATA;
+                }
+            }
+            ret = decode_rle(avctx, sub->rects[i], object->rle, object->rle_data_len);
+            if (ret < 0) {
+                if ((avctx->err_recognition & AV_EF_EXPLODE) ||
+                    ret == AVERROR(ENOMEM)) {
+                    avsubtitle_free(sub);
+                    return ret;
+                }
+                sub->rects[i]->w = 0;
+                sub->rects[i]->h = 0;
+                continue;
+            }
+        }
+        /* Allocate memory for colors */
+        sub->rects[i]->nb_colors    = 256;
+        sub->rects[i]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
+        if (!sub->rects[i]->pict.data[1]) {
+            avsubtitle_free(sub);
+            return AVERROR(ENOMEM);
+        }
 
-    /* Process bitmap */
-    sub->rects[0]->pict.linesize[0] = ctx->picture.w;
+        memcpy(sub->rects[i]->pict.data[1], palette->clut, sub->rects[i]->nb_colors * sizeof(uint32_t));
 
-    if (ctx->picture.rle) {
-        if (ctx->picture.rle_remaining_len)
-            av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n",
-                   ctx->picture.rle_data_len, ctx->picture.rle_remaining_len);
-        if(decode_rle(avctx, sub, ctx->picture.rle, ctx->picture.rle_data_len) < 0)
-            return 0;
     }
-    /* Allocate memory for colors */
-    sub->rects[0]->nb_colors    = 256;
-    sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
-
-    memcpy(sub->rects[0]->pict.data[1], ctx->clut, sub->rects[0]->nb_colors * sizeof(uint32_t));
-
     return 1;
 }
 
@@ -449,17 +609,16 @@ static int decode(AVCodecContext *avctx, void *data, int *data_size,
         if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf)
             break;
 
+        ret = 0;
         switch (segment_type) {
         case PALETTE_SEGMENT:
-            parse_palette_segment(avctx, buf, segment_length);
+            ret = parse_palette_segment(avctx, buf, segment_length);
             break;
-        case PICTURE_SEGMENT:
-            parse_picture_segment(avctx, buf, segment_length);
+        case OBJECT_SEGMENT:
+            ret = parse_object_segment(avctx, buf, segment_length);
             break;
         case PRESENTATION_SEGMENT:
             ret = parse_presentation_segment(avctx, buf, segment_length, avpkt->pts);
-            if (ret < 0)
-                return ret;
             break;
         case WINDOW_SEGMENT:
             /*
@@ -472,13 +631,18 @@ static int decode(AVCodecContext *avctx, void *data, int *data_size,
              */
             break;
         case DISPLAY_SEGMENT:
-            *data_size = display_end_segment(avctx, data, buf, segment_length);
+            ret = display_end_segment(avctx, data, buf, segment_length);
+            if (ret >= 0)
+                *data_size = ret;
             break;
         default:
             av_log(avctx, AV_LOG_ERROR, "Unknown subtitle segment type 0x%x, length %d\n",
                    segment_type, segment_length);
+            ret = AVERROR_INVALIDDATA;
             break;
         }
+        if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
+            return ret;
 
         buf += segment_length;
     }