h264parse element hangs with some video streams

Describe your issue

Possible regression: the h264parse element can hang with some video streams that work with previous versions, such as 1.22.1. From the logs, it appears to get into an infinite loop reporting skipping 0 and reparsing the same data indefinitely. The attached debug logs for the element may be helpful.

Expected Behavior

The h264parse element should always proceed.

Observed Behavior

The h264parse element hangs without reporting any errors for some streams. A previous gstreamer version 1.22.1, reading the same streams at the same time, did not have any issues.

Setup

Operating System: Ubuntu 20.04
Device: Computer
GStreamer Version: 1.24.1
Command line:

Steps to reproduce the bug

For some streams, this will happen with any command line directly or indirectly using h264parse. I have not been able to determine the exact nature of video streams that reproduce this, but I was able to capture h264parse debug logs when the problem occurred.

How reproducible is the bug?

Intermittent

Screenshots if relevant

Solutions you have tried

Related non-duplicate issues

Additional Information

When the problem occurs, the debug log indicates "skipping 0"


     h264parse gsth264parse.c:1970:gst_h264_parse_handle_frame:<h264parse0> not a complete nal found at offset 59984
     h264parse gsth264parse.c:1912:gst_h264_parse_handle_frame:<h264parse0> last parse position 59981

codecparsers_h264 gsth264parser.c:250:gst_h264_parse_nalu_header: Nal type 1, ref_idc 2
codecparsers_h264 gsth264parser.c:1577:gst_h264_parser_identify_nalu: Complete nal found. Off: 59984, Size: 28706
h264parse gsth264parse.c:1949:gst_h264_parse_handle_frame: complete nal (offset, size): (59984, 28706)
h264parse gsth264parse.c:1534:gst_h264_parse_update_backlog: vcl nal (1) added to backlog
codecparsers_h264 gsth264parser.c:2467:gst_h264_parser_parse_slice_hdr: parsing "Slice header", slice type 5
codecparsers_h264 gsth264parser.c:775:gst_h264_slice_parse_pred_weight_table: parsing "Prediction weight table"
codecparsers_h264 gsth264parser.c:709:gst_h264_slice_parse_dec_ref_pic_marking: parsing "Decoded reference picture marking"
h264parse gsth264parse.c:1058:gst_h264_parse_process_nal: processing nal of type 12 Filler Data, size 110
h264parse gsth264parse.c:2112:gst_h264_parse_handle_frame: skipping 59981
h264parse gsth264parse.c:250:gst_h264_parse_reset_frame: reset frame
h264parse gsth264parse.c:250:gst_h264_parse_reset_frame: reset frame
h264parse gsth264parse.c:1912:gst_h264_parse_handle_frame: last parse position 0
codecparsers_h264 gsth264parser.c:250:gst_h264_parse_nalu_header: Nal type 1, ref_idc 2
codecparsers_h264 gsth264parser.c:250:gst_h264_parse_nalu_header: Nal type 1, ref_idc 2
codecparsers_h264 gsth264parser.c:1577:gst_h264_parser_identify_nalu: Complete nal found. Off: 3, Size: 28706
h264parse gsth264parse.c:1949:gst_h264_parse_handle_frame: complete nal (offset, size): (3, 28706)
h264parse gsth264parse.c:1534:gst_h264_parse_update_backlog: vcl nal (1) added to backlog
codecparsers_h264 gsth264parser.c:2467:gst_h264_parser_parse_slice_hdr: parsing "Slice header", slice type 5
codecparsers_h264 gsth264parser.c:775:gst_h264_slice_parse_pred_weight_table: parsing "Prediction weight table"
codecparsers_h264 gsth264parser.c:709:gst_h264_slice_parse_dec_ref_pic_marking: parsing "Decoded reference picture marking"
h264parse gsth264parse.c:1058:gst_h264_parse_process_nal: processing nal of type 1 Slice, size 28706
h264parse gsth264parse.c:2112:gst_h264_parse_handle_frame: skipping 0

Once the "skipping 0" happens, it seems to loop forever trying to parse the same thing, this exact pattern repeats forever


codecparsers_h264 gsth264parser.c:1577:gst_h264_parser_identify_nalu: Complete nal found. Off: 3, Size: 28706
        h264parse gsth264parse.c:1949:gst_h264_parse_handle_frame: complete nal (offset, size): (3, 28706)
        h264parse gsth264parse.c:1534:gst_h264_parse_update_backlog: vcl nal (1) added to backlog
codecparsers_h264 gsth264parser.c:2467:gst_h264_parser_parse_slice_hdr: parsing "Slice header", slice type 5
codecparsers_h264 gsth264parser.c:775:gst_h264_slice_parse_pred_weight_table: parsing "Prediction weight table"
codecparsers_h264 gsth264parser.c:709:gst_h264_slice_parse_dec_ref_pic_marking: parsing "Decoded reference picture marking"
        h264parse gsth264parse.c:1058:gst_h264_parse_process_nal: processing nal of type 1 Slice, size 28706
        h264parse gsth264parse.c:2112:gst_h264_parse_handle_frame: skipping 0
        h264parse gsth264parse.c:250:gst_h264_parse_reset_frame: reset frame
        h264parse gsth264parse.c:1912:gst_h264_parse_handle_frame: last parse position 0
codecparsers_h264 gsth264parser.c:250:gst_h264_parse_nalu_header: Nal type 1, ref_idc 2
codecparsers_h264 gsth264parser.c:250:gst_h264_parse_nalu_header: Nal type 1, ref_idc 2
codecparsers_h264 gsth264parser.c:1577:gst_h264_parser_identify_nalu: Complete nal found. Off: 3, Size: 28706
        h264parse gsth264parse.c:1949:gst_h264_parse_handle_frame: complete nal (offset, size): (3, 28706)
        h264parse gsth264parse.c:1534:gst_h264_parse_update_backlog: vcl nal (1) added to backlog
codecparsers_h264 gsth264parser.c:2467:gst_h264_parser_parse_slice_hdr: parsing "Slice header", slice type 5
codecparsers_h264 gsth264parser.c:775:gst_h264_slice_parse_pred_weight_table: parsing "Prediction weight table"
codecparsers_h264 gsth264parser.c:709:gst_h264_slice_parse_dec_ref_pic_marking: parsing "Decoded reference picture marking"
        h264parse gsth264parse.c:1058:gst_h264_parse_process_nal: processing nal of type 1 Slice, size 28706
...repeats forever, apparently "skipping 0" and reparsing the same thing

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