[FFmpeg-devel] [PATCH] Ignore duplicate ID3 tags if vorbis tags exist

[Paul Arzelier]

You're right, I made a patch for libavformat/utils.c instead.

I modified a bit Ben's version and kept only the "spec-compliant flac 
files do not support ID3 tags" warning, I hope it's okay with you.

Paul

Le 26/01/2017 à 11:24, wm4 a écrit :
> On Thu, 26 Jan 2017 11:08:45 +0100
> Paul Arzelier <paul.arzelier at free.fr> wrote:
>
>>  From bb5dc73c42ad2e0bffd7e38fac18c6f01ec05ab3 Mon Sep 17 00:00:00 2001
>> From: Paul Arzelier <paul.arzelier at free.fr>
>> Date: Thu, 26 Jan 2017 11:04:44 +0100
>> Subject: [PATCH] Fixed behavior when id3 tags were found on FLAC files
>> Originally-by: Ben Boeckel <mathstuf at gmail.com>
>> ---
>>   libavformat/flacdec.c | 30 ++++++++++++++++++++++++++++++
>>   1 file changed, 30 insertions(+)
>>
>> diff --git a/libavformat/flacdec.c b/libavformat/flacdec.c
>> index 66baba5922..869936621b 100644
>> --- a/libavformat/flacdec.c
>> +++ b/libavformat/flacdec.c
>> @@ -48,6 +48,7 @@ static int flac_read_header(AVFormatContext *s)
>>       int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
>>       uint8_t header[4];
>>       uint8_t *buffer=NULL;
>> +    int has_id3 = 0;
>>       FLACDecContext *flac = s->priv_data;
>>       AVStream *st = avformat_new_stream(s, NULL);
>>       if (!st)
>> @@ -63,6 +64,22 @@ static int flac_read_header(AVFormatContext *s)
>>           return 0;
>>       }
>>   
>> +    if (av_dict_count(s->metadata)) {
>> +         /* XXX: Is there a better way to parse this out? ID3 parsing is done
>> +         * all the way out in avformat_open_input. */
>> +         has_id3 = 1;
>> +    }
>> +
>> +    if (has_id3) {
>> +         int level = AV_LOG_WARNING;
>> +         if (s->error_recognition & AV_EF_COMPLIANT)
>> +              level = AV_LOG_ERROR;
>> +         av_log(s, level, "Spec-compliant flac files do not support ID3 tags.\n");
>> +         if (s->error_recognition & AV_EF_EXPLODE)
>> +              return AVERROR_INVALIDDATA;
>> +    }
>> +
>> +
>>       /* process metadata blocks */
>>       while (!avio_feof(s->pb) && !metadata_last) {
>>           if (avio_read(s->pb, header, 4) != 4)
>> @@ -173,8 +190,16 @@ static int flac_read_header(AVFormatContext *s)
>>               }
>>               /* process supported blocks other than STREAMINFO */
>>               if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
>> +                AVDictionary *other_meta = NULL;
>>                   AVDictionaryEntry *chmask;
>>   
>> +                if (has_id3) {
>> +                    av_log(s, AV_LOG_VERBOSE, "FLAC found with ID3 and vorbis tags; ignoring ID3 tags also provided by vorbis.\n");
>> +
>> +                    other_meta = s->metadata;
>> +                    s->metadata = NULL;
>> +                }
>> +
>>                   ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
>>                   if (ret < 0) {
>>                       av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
>> @@ -182,6 +207,11 @@ static int flac_read_header(AVFormatContext *s)
>>                       s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
>>                   }
>>   
>> +                if (other_meta) {
>> +                    av_dict_copy(&s->metadata, other_meta, AV_DICT_DONT_OVERWRITE);
>> +                    av_dict_free(&other_meta);
>> +                }
>> +
>>                   /* parse the channels mask if present */
>>                   chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
>>                   if (chmask) {
> I feel like there should be a more general solution.
>
> ID3v2 tags are read by common code, and such tags are supported by
> basically all file formats in libavformat due to the way it's
> implemented.
>
> This fixes it for FLAC only. Are we going to duplicate this for every
> format?
>
> I suggest reading id3 tags into a separate dict instead, and then
> copying it in libavformat/utils.c after read_header if the demuxer
> hasn't set any tags.
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-- 
Paul ARZELIER
Élève ingénieur à l'École Centrale de Lille
2014-2017

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