Merge commit 'c7d4de3d'

* commit 'c7d4de3d':
  rtpdec_vp8: Don't return known-broken packets
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/rtpdec_vp8.c

@@ -34,8 +34,33 @@
 struct PayloadContext {
     AVIOContext *data;
     uint32_t     timestamp;
+    int          is_keyframe;
+    int          sequence_ok;
+    int          first_part_size;
+    uint16_t     prev_seq;
+    int          prev_pictureid;
+    int          broken_frame;
 };
 
+static void vp8_free_buffer(PayloadContext *vp8)
+{
+    uint8_t *tmp;
+    if (!vp8->data)
+        return;
+    avio_close_dyn_buf(vp8->data, &tmp);
+    av_free(tmp);
+    vp8->data = NULL;
+}
+
+static int vp8_broken_sequence(AVFormatContext *ctx, PayloadContext *vp8,
+                               const char *msg)
+{
+    vp8->sequence_ok = 0;
+    av_log(ctx, AV_LOG_WARNING, "%s", msg);
+    vp8_free_buffer(vp8);
+    return AVERROR(EAGAIN);
+}
+
 static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8,
                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                              const uint8_t *buf, int len, uint16_t seq,
@@ -45,6 +70,19 @@ static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8,
     int extended_bits, part_id;
     int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0,
         keyidx_present = 0;
+    int pictureid = -1, pictureid_mask;
+    int returned_old_frame = 0;
+    uint32_t old_timestamp;
+
+    if (!buf) {
+        if (vp8->data) {
+            int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+            if (ret < 0)
+                return ret;
+            return 0;
+        }
+        return AVERROR(EAGAIN);
+    }
 
     if (len < 1)
         return AVERROR_INVALIDDATA;
@@ -66,12 +104,21 @@ static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8,
         len--;
     }
     if (pictureid_present) {
-        int size;
         if (len < 1)
             return AVERROR_INVALIDDATA;
-        size = buf[0] & 0x80 ? 2 : 1;
-        buf += size;
-        len -= size;
+        if (buf[0] & 0x80) {
+            if (len < 2)
+                return AVERROR_INVALIDDATA;
+            pictureid = AV_RB16(buf) & 0x7fff;
+            pictureid_mask = 0x7fff;
+            buf += 2;
+            len -= 2;
+        } else {
+            pictureid = buf[0] & 0x7f;
+            pictureid_mask = 0x7f;
+            buf++;
+            len--;
+        }
     }
     if (tl0picidx_present) {
         // Ignoring temporal level zero index
@@ -86,31 +133,116 @@ static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8,
     if (len < 1)
         return AVERROR_INVALIDDATA;
 
-    if (start_partition && part_id == 0) {
+    if (start_partition && part_id == 0 && len >= 3) {
         int res;
-        if (vp8->data) {
-            uint8_t *tmp;
-            avio_close_dyn_buf(vp8->data, &tmp);
-            av_free(tmp);
-            vp8->data = NULL;
+        int non_key = buf[0] & 0x01;
+        if (!non_key) {
+            vp8_free_buffer(vp8);
+            // Keyframe, decoding ok again
+            vp8->sequence_ok = 1;
+        } else {
+            int can_continue = vp8->data && !vp8->is_keyframe &&
+                               avio_tell(vp8->data) >= vp8->first_part_size;
+            if (!vp8->sequence_ok)
+                return AVERROR(EAGAIN);
+            if (pictureid >= 0) {
+                if (pictureid != ((vp8->prev_pictureid + 1) & pictureid_mask)) {
+                    return vp8_broken_sequence(ctx, vp8,
+                                               "Missed a picture, sequence broken\n");
+                } else {
+                    if (vp8->data && !can_continue)
+                        return vp8_broken_sequence(ctx, vp8,
+                                                   "Missed a picture, sequence broken\n");
+                }
+            } else {
+                uint16_t expected_seq = vp8->prev_seq + 1;
+                int16_t diff = seq - expected_seq;
+                if (vp8->data) {
+                    // No picture id, so we can't know if missed packets
+                    // contained any new frames. If diff == 0, we did get
+                    // later packets from the same frame (matching timestamp),
+                    // so we know we didn't miss any frame. If diff == 1 and
+                    // we still have data (not flushed by the end of frame
+                    // marker), the single missed packet must have been part
+                    // of the same frame.
+                    if ((diff == 0 || diff == 1) && can_continue) {
+                        // Proceed with what we have
+                    } else {
+                        return vp8_broken_sequence(ctx, vp8,
+                                                   "Missed too much, sequence broken\n");
+                    }
+                } else {
+                    if (diff != 0)
+                        return vp8_broken_sequence(ctx, vp8,
+                                                   "Missed unknown data, sequence broken\n");
+                }
+            }
+            if (vp8->data) {
+                if (avio_tell(vp8->data) >= vp8->first_part_size) {
+                    int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+                    if (ret < 0)
+                        return ret;
+                    pkt->size = vp8->first_part_size;
+                    returned_old_frame = 1;
+                    old_timestamp = vp8->timestamp;
+                } else {
+                    // Shouldn't happen
+                    vp8_free_buffer(vp8);
+                }
+            }
         }
+        vp8->first_part_size = (AV_RL16(&buf[1]) << 3 | buf[0] >> 5) + 3;
         if ((res = avio_open_dyn_buf(&vp8->data)) < 0)
             return res;
         vp8->timestamp = *timestamp;
-    }
+        vp8->broken_frame = 0;
+        vp8->prev_pictureid = pictureid;
+        vp8->is_keyframe = !non_key;
+    } else {
+        uint16_t expected_seq = vp8->prev_seq + 1;
 
-    if (!vp8->data || vp8->timestamp != *timestamp) {
-        av_log(ctx, AV_LOG_WARNING,
-               "Received no start marker; dropping frame\n");
-        return AVERROR(EAGAIN);
+        if (!vp8->sequence_ok)
+            return AVERROR(EAGAIN);
+
+        if (vp8->timestamp != *timestamp) {
+            // Missed the start of the new frame, sequence broken
+            vp8->sequence_ok = 0;
+            av_log(ctx, AV_LOG_WARNING,
+                   "Received no start marker; dropping frame\n");
+            vp8_free_buffer(vp8);
+            return AVERROR(EAGAIN);
+        }
+
+        if (seq != expected_seq) {
+            if (vp8->is_keyframe) {
+                return vp8_broken_sequence(ctx, vp8,
+                                           "Missed part of a keyframe, sequence broken\n");
+            } else if (vp8->data && avio_tell(vp8->data) >= vp8->first_part_size) {
+                vp8->broken_frame = 1;
+            } else {
+                return vp8_broken_sequence(ctx, vp8,
+                                           "Missed part of the first partition, sequence broken\n");
+            }
+        }
     }
 
+    if (!vp8->data)
+        return vp8_broken_sequence(ctx, vp8, "Received no start marker\n");
+
+    vp8->prev_seq = seq;
     avio_write(vp8->data, buf, len);
 
     if (end_packet) {
-        int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+        int ret;
+        if (returned_old_frame) {
+            *timestamp = old_timestamp;
+            return 1;
+        }
+        ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
         if (ret < 0)
             return ret;
+        if (vp8->broken_frame)
+            pkt->size = vp8->first_part_size;
         return 0;
     }
 
@@ -124,11 +256,7 @@ static PayloadContext *vp8_new_context(void)
 
 static void vp8_free_context(PayloadContext *vp8)
 {
-    if (vp8->data) {
-        uint8_t *tmp;
-        avio_close_dyn_buf(vp8->data, &tmp);
-        av_free(tmp);
-    }
+    vp8_free_buffer(vp8);
     av_free(vp8);
 }