[FFmpeg-devel] [PATCH 03/18] avformat/id3v2: allow ID3 parsing without AVFormatContext

[Anssi Hannula]

30.12.2013 18:23, Michael Niedermayer kirjoitti:
> On Mon, Dec 30, 2013 at 01:14:17PM +0200, Anssi Hannula wrote:
>> Add ff_id3v2_read_dict() for parsing without AVFormatContext, but
>> instead with AVIOContext and AVDictionary.
>>
>> Chapter parsing is the only functionality that actually needs
>> AVFormatContext, and AFAICS it should be modified to write the data to
>> ID3v2ExtraMeta first, from where it can be implanted to AVFormatContext
>> (like it is done with read_apic() and ff_id3v2_parse_apic()). That is
>> outside the scope of this patch, though, so AVFormatContext parameter is
>> still kept in a few more codepaths than I would prefer.
>>
>> Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
>> ---
>>
>> This causes a lot of av_logs with NULL context, does it matter and if
>> so, how should it be solved?
>>
>>  libavformat/id3v2.c | 160 ++++++++++++++++++++++++++++++----------------------
>>  libavformat/id3v2.h |  16 +++++-
>>  2 files changed, 106 insertions(+), 70 deletions(-)
>>
>> diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
>> index 3eb368e..0ff2df0 100644
>> --- a/libavformat/id3v2.c
>> +++ b/libavformat/id3v2.c
>> @@ -193,7 +193,7 @@ static void free_geobtag(void *obj)
>>   * actually read.
>>   * @returns 0 if no error occurred, dst is uninitialized on error
>>   */
>> -static int decode_str(AVFormatContext *s, AVIOContext *pb, int encoding,
>> +static int decode_str(AVIOContext *pb, int encoding,
>>                        uint8_t **dst, int *maxread)
>>  {
>>      int ret;
>> @@ -204,7 +204,7 @@ static int decode_str(AVFormatContext *s, AVIOContext *pb, int encoding,
>>      AVIOContext *dynbuf;
>>  
>>      if ((ret = avio_open_dyn_buf(&dynbuf)) < 0) {
>> -        av_log(s, AV_LOG_ERROR, "Error opening memory stream\n");
>> +        av_log(NULL, AV_LOG_ERROR, "Error opening memory stream\n");
> 
> some (void*) context for av_log() could be kept, this would also
> make the patch smaller

Yeah, I could keep the otherwise unneeded AVFormatContext parameters
around just for av_logs if that is preferred (though it can be NULL,
which is the reason I dropped it completely to avoid any new code
relying on it).

Will do so unless you say otherwise.

-- 
Anssi Hannula