[FFmpeg-devel] [PATCH]select attribute of tee pseudo demuxer may contain multiple stream specifiers

[Bodecs Bela]

2015.10.10. 19:33 keltezéssel, Nicolas George írta:
> L'octidi 18 vendémiaire, an CCXXIV, Bodecs Bela a écrit :
>> I have altered the code to work correctly in situations with multiple
>> streams. I have also tested it with your  command.
> Thanks, it looks almost good for apply.
>
> Your other patches were made with git format-patch, so that is ok; do not
> forget the "signed-off-by" tag (--signoff option), just to be on the safe
> side legally.
>
>> --- a/doc/muxers.texi
>> +++ b/doc/muxers.texi
>> @@ -1272,7 +1272,8 @@
>>   @item select
>>   Select the streams that should be mapped to the slave output,
>>   specified by a stream specifier. If not specified, this defaults to
>> -all the input streams.
>> +all the input streams. You may use multiple stream specifiers
>> +separated by commas (@code{,}) e.g.: @code{a:0,v}
>>   @end table
>>   
>>   @subsection Examples
>> diff --git a/libavformat/tee.c b/libavformat/tee.c
>> index c619eae..324aa43 100644
>> --- a/libavformat/tee.c
>> +++ b/libavformat/tee.c
>> @@ -47,6 +47,7 @@
>>   static const char *const slave_opt_close = "]";
>>   static const char *const slave_opt_delim = ":]"; /* must have the close too */
>>   static const char *const slave_bsfs_spec_sep = "/";
>> +static const char *const slave_select_sep = ",";
>>   
>>   static const AVClass tee_muxer_class = {
>>       .class_name = "Tee muxer",
>> @@ -142,6 +143,8 @@
>>       AVFormatContext *avf2 = NULL;
>>       AVStream *st, *st2;
>>       int stream_count;
>> +    int fullret;
>> +    char *subselect = NULL, *next_subselect = NULL, *first_subselect = NULL, *tmp_select = NULL;
>>   
>>       if ((ret = parse_slave_options(avf, slave, &options, &filename)) < 0)
>>           return ret;
>> @@ -172,15 +175,33 @@
>>       for (i = 0; i < avf->nb_streams; i++) {
>>           st = avf->streams[i];
>>           if (select) {
>> -            ret = avformat_match_stream_specifier(avf, avf->streams[i], select);
>> -            if (ret < 0) {
>> -                av_log(avf, AV_LOG_ERROR,
>> -                       "Invalid stream specifier '%s' for output '%s'\n",
>> -                       select, slave);
>> +            tmp_select = av_strdup(select);  // av_strtok is destructive so we regenerate it in each loop
>> +            if (!tmp_select) {
>> +                av_log(avf, AV_LOG_ERROR, "Unexpected internal memory allocation error occured during string duplication\n");
>>                   goto end;
> ret needs to be set to some value before jumping to end. Setting it to
> AVERROR(ENOMEM) makes the error message unnecessary; the code usually does
> not print a message for OOM.
>
>>               }
>> +            fullret = 0;
>> +            first_subselect = tmp_select;
>> +            next_subselect = NULL;
>> +            while (subselect = av_strtok(first_subselect, slave_select_sep, &next_subselect)) {
>> +                first_subselect = NULL;
>>   
>> -            if (ret == 0) { /* no match */
>> +                ret = avformat_match_stream_specifier(avf, avf->streams[i], subselect);
>> +                if (ret < 0) {
>> +                    av_log(avf, AV_LOG_ERROR,
>> +                           "Invalid stream specifier '%s' for output '%s'\n",
>> +                           subselect, slave);
>> +                    av_free(tmp_select);
>> +                    goto end;
>> +                }
>> +                if (ret != 0) {
>> +                    fullret = 1; // match
>> +                    break;
>> +                }
>> +            }
>> +            av_free(tmp_select);
> This code is safe. For extra robustness, it could ensure that tmp_select is
> NULL when not used (initing to NULL and using av_freep()), and move the free
> in the error case to the end clause. But I do not insist on that change.
>
>> +
>> +            if (fullret == 0) { /* no match */
>>                   tee_slave->stream_map[i] = -1;
>>                   continue;
>>               }
> Regards,
>
>
>
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I have altered the code as you wrote.

best regards,

Bela Bodecs
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