diff mbox series

[FFmpeg-devel,v6,08/22] h264_redundant_pps: Make it reference-compatible

Message ID 20200727163237.23371-9-sw@jkqxz.net
State New
Headers show
Series CBS unit type tables and assorted related stuff
Related show

Checks

Context Check Description
andriy/default pending
andriy/make success Make finished
andriy/make_fate success Make fate finished

Commit Message

Mark Thompson July 27, 2020, 4:32 p.m. UTC
From: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

Since c6a63e11092c975b89d824f08682fe31948d3686, the parameter sets
modified as content of PPS units were references shared with the
CodedBitstreamH264Context, so modifying them alters the parsing process
of future access units which meant that frames often got discarded
because invalid values were parsed. This patch makes h264_redundant_pps
compatible with the reality of reference-counted parameter sets.

Fixes #7807.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Mark Thompson <sw@jkqxz.net>
---
 libavcodec/h264_redundant_pps_bsf.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/libavcodec/h264_redundant_pps_bsf.c b/libavcodec/h264_redundant_pps_bsf.c
index a8af4105cf..cf41abe96c 100644
--- a/libavcodec/h264_redundant_pps_bsf.c
+++ b/libavcodec/h264_redundant_pps_bsf.c
@@ -41,8 +41,19 @@  typedef struct H264RedundantPPSContext {
 
 
 static int h264_redundant_pps_fixup_pps(H264RedundantPPSContext *ctx,
-                                        H264RawPPS *pps)
+                                        CodedBitstreamUnit *unit)
 {
+    H264RawPPS *pps;
+    int err;
+
+    // The changes we are about to perform affect the parsing process,
+    // so we must make sure that the PPS is writable, otherwise the
+    // parsing of future slices will be incorrect and even raise errors.
+    err = ff_cbs_make_unit_writable(ctx->input, unit);
+    if (err < 0)
+        return err;
+    pps = unit->content;
+
     // Record the current value of pic_init_qp in order to fix up
     // following slices, then overwrite with the global value.
     ctx->current_pic_init_qp = pps->pic_init_qp_minus26 + 26;
@@ -89,7 +100,7 @@  static int h264_redundant_pps_filter(AVBSFContext *bsf, AVPacket *pkt)
         if (nal->type == H264_NAL_SPS)
             au_has_sps = 1;
         if (nal->type == H264_NAL_PPS) {
-            err = h264_redundant_pps_fixup_pps(ctx, nal->content);
+            err = h264_redundant_pps_fixup_pps(ctx, nal);
             if (err < 0)
                 goto fail;
             if (!au_has_sps) {
@@ -145,7 +156,7 @@  static int h264_redundant_pps_init(AVBSFContext *bsf)
 
         for (i = 0; i < au->nb_units; i++) {
             if (au->units[i].type == H264_NAL_PPS) {
-                err = h264_redundant_pps_fixup_pps(ctx, au->units[i].content);
+                err = h264_redundant_pps_fixup_pps(ctx, &au->units[i]);
                 if (err < 0)
                     goto fail;
             }