[FFmpeg-devel] [PATCH] Revert "avformat/flvdec: Check that sizes match and resync if not"

[wm4]

This reverts commit cbbd906be6150be38dfc14b6bc67dcac8da8aea4.

It broke rtmp fatally, at least some cases of it.
---
Better fixes welcome, but I'd like if this regression could be fixed
quickly. On the other hand, there's no evidence that the reverted commit
was needed for anything.
---
 libavformat/flvdec.c | 48 +-----------------------------------------------
 1 file changed, 1 insertion(+), 47 deletions(-)

diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index a59c07d..317bfb2 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -39,8 +39,6 @@
 
 #define VALIDATE_INDEX_TS_THRESH 2500
 
-#define RESYNC_BUFFER_SIZE (1<<20)
-
 typedef struct FLVContext {
     const AVClass *class; ///< Class for private options.
     int trust_metadata;   ///< configure streams according onMetaData
@@ -57,8 +55,6 @@ typedef struct FLVContext {
     int validate_count;
     int searched_for_end;
 
-    uint8_t resync_buffer[2*RESYNC_BUFFER_SIZE];
-
     int broken_sizes;
 } FLVContext;
 
@@ -805,36 +801,6 @@ skip:
     return ret;
 }
 
-static int resync(AVFormatContext *s)
-{
-    FLVContext *flv = s->priv_data;
-    int64_t i;
-    int64_t pos = avio_tell(s->pb);
-
-    for (i=0; !avio_feof(s->pb); i++) {
-        int j  = i & (RESYNC_BUFFER_SIZE-1);
-        int j1 = j + RESYNC_BUFFER_SIZE;
-        flv->resync_buffer[j ] =
-        flv->resync_buffer[j1] = avio_r8(s->pb);
-
-        if (i > 22) {
-            unsigned lsize2 = AV_RB32(flv->resync_buffer + j1 - 4);
-            if (lsize2 >= 11 && lsize2 + 8LL < FFMIN(i, RESYNC_BUFFER_SIZE)) {
-                unsigned  size2 = AV_RB24(flv->resync_buffer + j1 - lsize2 + 1 - 4);
-                unsigned lsize1 = AV_RB32(flv->resync_buffer + j1 - lsize2 - 8);
-                if (lsize1 >= 11 && lsize1 + 8LL + lsize2 < FFMIN(i, RESYNC_BUFFER_SIZE)) {
-                    unsigned  size1 = AV_RB24(flv->resync_buffer + j1 - lsize1 + 1 - lsize2 - 8);
-                    if (size1 == lsize1 - 11 && size2  == lsize2 - 11) {
-                        avio_seek(s->pb, pos + i - lsize1 - lsize2 - 8, SEEK_SET);
-                        return 1;
-                    }
-                }
-            }
-        }
-    }
-    return AVERROR_EOF;
-}
-
 static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     FLVContext *flv = s->priv_data;
@@ -847,14 +813,11 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
     int av_uninit(sample_rate);
     AVStream *st    = NULL;
     int last = -1;
-    int orig_size;
 
-retry:
     /* pkt size is repeated at end. skip it */
     for (;; last = avio_rb32(s->pb)) {
         pos  = avio_tell(s->pb);
         type = (avio_r8(s->pb) & 0x1F);
-        orig_size =
         size = avio_rb24(s->pb);
         dts  = avio_rb24(s->pb);
         dts |= avio_r8(s->pb) << 24;
@@ -1137,16 +1100,7 @@ retry_duration:
         pkt->flags |= AV_PKT_FLAG_KEY;
 
 leave:
-    last = avio_rb32(s->pb);
-    if (last != orig_size + 11 && !flv->broken_sizes) {
-        av_log(s, AV_LOG_ERROR, "Packet mismatch %d %d\n", last, orig_size + 11);
-        avio_seek(s->pb, pos + 1, SEEK_SET);
-        ret = resync(s);
-        av_free_packet(pkt);
-        if (ret >= 0) {
-            goto retry;
-        }
-    }
+    avio_skip(s->pb, 4);
     return ret;
 }
 
-- 
2.5.1