[FFmpeg-devel] [PATCH, v2] lavc/hevc_parser: add 4 bytes startcode condition and update FATE

[Linjie Fu]

The startcode before VPS,SPS,PPS and the first NALU in an AU is 4 bytes.
Blindly taking the startcode as 3 bytes will leave 0x00 in last packet
and may lead to some warnings in parse_nal_units when s->flags is set to
PARSER_FLAG_COMPLETE_FRAMES.

Add 4 bytes startcode condition in hevc_find_frame_end.
Modify the code to print the buf_size like in H264 and reduce the duplication.

Update the FATE checksum for fate-hevc-bsf-mp4toannexb:
The ref output has redundant 0x00 at the end of the SUFFIX_SEI:
{ 50 01 84 31 00 19 39 77 d0 7b 3f bd 1e 09 38 9a 79 41
c0 16 11 da 18 aa 0a db 2b 19 fa 47 3f 0f 67 4a 91 9c a1
12 72 67 d6 f0 8f 66 ee 95 f9 e2 b9 ba 23 9a e8 80 00 }

To verify the output of FATE:
ffmpeg -i hevc-conformance/WPP_A_ericsson_MAIN10_2.bit -c copy -flags \
        +bitexact hevc-mp4.mov
ffmpeg -i hevc-mp4.mov -c:v copy -fflags +bitexact -f hevc hevc.out

Signed-off-by: Linjie Fu <linjie.fu at intel.com>
---
[v2]: Update FATE checksum

 libavcodec/hevc_parser.c | 15 ++++++++++-----
 tests/fate/hevc.mak      |  2 +-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/libavcodec/hevc_parser.c b/libavcodec/hevc_parser.c
index 369d1338d0..aa216e3c8d 100644
--- a/libavcodec/hevc_parser.c
+++ b/libavcodec/hevc_parser.c
@@ -32,6 +32,7 @@
 #include "parser.h"
 
 #define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
+#define START_CODE_4 0x00000001 ///< start_code_4bytes
 
 #define IS_IRAP_NAL(nal) (nal->type >= 16 && nal->type <= 23)
 #define IS_IDR_NAL(nal) (nal->type == HEVC_NAL_IDR_W_RADL || nal->type == HEVC_NAL_IDR_N_LP)
@@ -239,7 +240,7 @@ static int parse_nal_units(AVCodecParserContext *s, const uint8_t *buf,
         }
     }
     /* didn't find a picture! */
-    av_log(avctx, AV_LOG_ERROR, "missing picture in access unit\n");
+    av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
     return -1;
 }
 
@@ -267,8 +268,7 @@ static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
         if ((nut >= HEVC_NAL_VPS && nut <= HEVC_NAL_EOB_NUT) || nut == HEVC_NAL_SEI_PREFIX ||
             (nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
             if (pc->frame_start_found) {
-                pc->frame_start_found = 0;
-                return i - 5;
+                goto found;
             }
         } else if (nut <= HEVC_NAL_RASL_R ||
                    (nut >= HEVC_NAL_BLA_W_LP && nut <= HEVC_NAL_CRA_NUT)) {
@@ -277,14 +277,19 @@ static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
                 if (!pc->frame_start_found) {
                     pc->frame_start_found = 1;
                 } else { // First slice of next frame found
-                    pc->frame_start_found = 0;
-                    return i - 5;
+                    goto found;
                 }
             }
         }
     }
 
     return END_NOT_FOUND;
+
+found:
+    pc->frame_start_found = 0;
+    if (((pc->state64 >> 3 * 8) & 0xFFFFFFFF) == START_CODE_4)
+        return i - 6;
+    return i - 5;
 }
 
 static int hevc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
diff --git a/tests/fate/hevc.mak b/tests/fate/hevc.mak
index db3ea19340..ab8da53535 100644
--- a/tests/fate/hevc.mak
+++ b/tests/fate/hevc.mak
@@ -238,7 +238,7 @@ FATE_HEVC-$(call ALLYES, HEVC_DEMUXER MOV_DEMUXER HEVC_MP4TOANNEXB_BSF MOV_MUXER
 fate-hevc-bsf-mp4toannexb: tests/data/hevc-mp4.mov
 fate-hevc-bsf-mp4toannexb: CMD = md5 -i $(TARGET_PATH)/tests/data/hevc-mp4.mov -c:v copy -fflags +bitexact -f hevc
 fate-hevc-bsf-mp4toannexb: CMP = oneline
-fate-hevc-bsf-mp4toannexb: REF = 1873662a3af1848c37e4eb25722c8df9
+fate-hevc-bsf-mp4toannexb: REF = 73019329ed7f81c24f9af67c34c640c0
 
 fate-hevc-skiploopfilter: CMD = framemd5 -skip_loop_filter nokey -i $(TARGET_SAMPLES)/hevc-conformance/SAO_D_Samsung_5.bit -sws_flags bitexact
 FATE_HEVC += fate-hevc-skiploopfilter
-- 
2.17.1