[FFmpeg-devel] h264: fix RTSP stream decoding

[sergey at gavrushkin.com]

Hello,

FFmpeg stop working with the latest model of camera that I work now. I've investigated it and found that "bad" commit is 98c97994c5b90bdae02accb155eeceeb5224b8ef. There was additional check for ret value and err_recognition, that was ignored while refactoring to h264_parse.c function.

Test RTSP streams are available here:

rtsp://admin:123456@69.42.237.230:1569/mpeg4cif <rtsp://admin:123456@69.42.237.230:1569/mpeg4cif>
rtsp://admin:123456@69.42.237.230:1568/mpeg4cif

P.S. It is my first patch so please write any notes what I should provide for accepting. 

Thank you,
Sergey


-------------------------------------



From e90ef7b56d4147ff6555468f0154321b55596846 Mon Sep 17 00:00:00 2001
From: Sergey Gavrushkin <sergey at gavrushkin.com>
Date: Fri, 29 Dec 2017 20:03:50 +0300
Subject: [PATCH] h264: fix RTSP stream decoding

It is a regression fix for an issue that was introduced in commit
98c97994c5b90bdae02accb155eeceeb5224b8ef. Variable err_recognition is
ignored while extradata is decoded and the whole decoding process is
failed due to timeout.
---
 libavcodec/h264_parse.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libavcodec/h264_parse.c b/libavcodec/h264_parse.c
index fee28d9..009d50c 100644
--- a/libavcodec/h264_parse.c
+++ b/libavcodec/h264_parse.c
@@ -347,7 +347,7 @@ int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
 }
 
 static int decode_extradata_ps(const uint8_t *data, int size, H264ParamSets *ps,
-                               int is_avc, void *logctx)
+                               int is_avc, int err_recognition, void *logctx)
 {
     H2645Packet pkt = { 0 };
     int i, ret = 0;
@@ -363,13 +363,13 @@ static int decode_extradata_ps(const uint8_t *data, int size, H264ParamSets *ps,
         switch (nal->type) {
         case H264_NAL_SPS:
             ret = ff_h264_decode_seq_parameter_set(&nal->gb, logctx, ps, 0);
-            if (ret < 0)
+            if (ret < 0 && (err_recognition & AV_EF_EXPLODE))
                 goto fail;
             break;
         case H264_NAL_PPS:
             ret = ff_h264_decode_picture_parameter_set(&nal->gb, logctx, ps,
                                                        nal->size_bits);
-            if (ret < 0)
+            if (ret < 0 && (err_recognition & AV_EF_EXPLODE))
                 goto fail;
             break;
         default:
@@ -393,7 +393,7 @@ static int decode_extradata_ps_mp4(const uint8_t *buf, int buf_size, H264ParamSe
 {
     int ret;
 
-    ret = decode_extradata_ps(buf, buf_size, ps, 1, logctx);
+    ret = decode_extradata_ps(buf, buf_size, ps, 1, err_recognition, logctx);
     if (ret < 0 && !(err_recognition & AV_EF_EXPLODE)) {
         GetByteContext gbc;
         PutByteContext pbc;
@@ -425,7 +425,7 @@ static int decode_extradata_ps_mp4(const uint8_t *buf, int buf_size, H264ParamSe
         escaped_buf_size = bytestream2_tell_p(&pbc);
         AV_WB16(escaped_buf, escaped_buf_size - 2);
 
-        (void)decode_extradata_ps(escaped_buf, escaped_buf_size, ps, 1, logctx);
+        (void)decode_extradata_ps(escaped_buf, escaped_buf_size, ps, 1, err_recognition, logctx);
         // lorex.mp4 decodes ok even with extradata decoding failing
         av_freep(&escaped_buf);
     }
@@ -486,7 +486,7 @@ int ff_h264_decode_extradata(const uint8_t *data, int size, H264ParamSets *ps,
         *nal_length_size = (data[4] & 0x03) + 1;
     } else {
         *is_avc = 0;
-        ret = decode_extradata_ps(data, size, ps, 0, logctx);
+        ret = decode_extradata_ps(data, size, ps, 0, err_recognition, logctx);
         if (ret < 0)
             return ret;
     }
-- 
2.6.4