[FFmpeg-devel] [PATCH] avformat/flvdec: enhance parsing timestamps

[Marton Balint]

On Fri, 14 May 2021, Anton Khirnov wrote:

> Quoting Marton Balint (2021-05-12 20:55:45)
>> Take into account timezone. Use millisecond precision. Maybe we could also use
>> nanosecond, but there were some float rounding concerns.
>>
>> Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>  libavformat/flvdec.c     | 13 ++-----------
>>  tests/ref/fate/flv-demux |  2 +-
>>  2 files changed, 3 insertions(+), 12 deletions(-)
>>
>> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
>> index ddaceaafe4..3791687072 100644
>> --- a/libavformat/flvdec.c
>> +++ b/libavformat/flvdec.c
>> @@ -28,6 +28,7 @@
>>  #include "libavutil/channel_layout.h"
>>  #include "libavutil/dict.h"
>>  #include "libavutil/opt.h"
>> +#include "libavutil/internal.h"
>>  #include "libavutil/intfloat.h"
>>  #include "libavutil/mathematics.h"
>>  #include "libavutil/time_internal.h"
>> @@ -682,17 +683,7 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream,
>>          } else if (amf_type == AMF_DATA_TYPE_STRING) {
>>              av_dict_set(&s->metadata, key, str_val, 0);
>>          } else if (amf_type == AMF_DATA_TYPE_DATE) {
>> -            time_t time;
>> -            struct tm t;
>> -            char datestr[128];
>> -            time =  date.milliseconds / 1000; // to seconds
>> -            gmtime_r(&time, &t);
>> -
>> -            // timezone is ignored, since there is no easy way to offset the UTC
>> -            // timestamp into the specified timezone
>> -            strftime(datestr, sizeof(datestr), "%Y-%m-%dT%H:%M:%SZ", &t);
>> -
>> -            av_dict_set(&s->metadata, key, datestr, 0);
>> +            avpriv_dict_set_timestamp(&s->metadata, key, -date.timezone * 60000000LL + 1000 * (int64_t)date.milliseconds);
>
> This is wrong -- date.milliseconds is in UTC, if you add the timezone
> offset it will no longer be in UTC.

Indeed, I misunderstood the specs... MediaInfo also ignores the time zone. 
Will send a v2.

Thanks,
Marton