[FFmpeg-devel] [PATCH]lavf/img2dec: Auto-detect svg images

[Carl Eugen Hoyos]

2017-10-02 11:42 GMT+02:00 Carl Eugen Hoyos <ceffmpeg at gmail.com>:
> 2017-10-02 7:52 GMT+02:00 Clément Bœsch <u at pkh.me>:
>> On Mon, Oct 02, 2017 at 01:20:15AM +0200, Carl Eugen Hoyos wrote:
>>> Hi!
>>>
>>> Attached patch implements auto-detection of svg images.
>>>
>>> Please review, Carl Eugen
>>
>>> From f06137f38f166740565e58d5c7c88777508f59ec Mon Sep 17 00:00:00 2001
>>> From: Carl Eugen Hoyos <ceffmpeg at gmail.com>
>>> Date: Mon, 2 Oct 2017 01:13:29 +0200
>>> Subject: [PATCH] lavf/img2dec: Auto-detect svg images.
>>>
>>> ---
>>>  libavformat/img2dec.c |   17 +++++++++++++++--
>>>  1 file changed, 15 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/libavformat/img2dec.c b/libavformat/img2dec.c
>>> index 19cae87..468c820 100644
>>> --- a/libavformat/img2dec.c
>>> +++ b/libavformat/img2dec.c
>>> @@ -34,6 +34,7 @@
>>>  #include "internal.h"
>>>  #include "img2.h"
>>>  #include "libavcodec/mjpeg.h"
>>> +#include "subtitles.h"
>>>
>>>  #if HAVE_GLOB
>>>  /* Locally define as 0 (bitwise-OR no-op) any missing glob options that
>>> @@ -875,8 +876,20 @@ static int sunrast_probe(AVProbeData *p)
>>>
>>>  static int svg_probe(AVProbeData *p)
>>>  {
>>> -    if (av_match_ext(p->filename, "svg") || av_match_ext(p->filename, "svgz"))
>>> -        return AVPROBE_SCORE_EXTENSION + 1;
>>> +    const uint8_t *b = p->buf;
>>> +    const uint8_t *end = p->buf + p->buf_size;
>>> +    if (memcmp(p->buf, "<?xml", 5))
>>> +        return 0;
>>> +    while (b < end) {
>>> +        b += ff_subtitles_next_line(b);
>>> +        if (b >= end)
>>> +            return 0;
>>
>>> +        if (!strstr(b, "<!DOCTYPE "))
>>> +            continue;
>>
>> at least the svg from inkscape do not have a doctype
>
> Wrong check, thank you.
>
>>> +        b += 9;
>>> +        if (strstr(b, "svg"))
>>> +            return AVPROBE_SCORE_MAX;
>>> +    }
>>
>> don't you want to keep an extension fallback?
>
> That's done by the image2 demuxer.
>
>> also, I would guess strstr() is going to be slow, so maybe
>> just look for a line starting with "<svg".
>
> Done, thank you.
>
> New patch attached, Carl Eugen

Patch applied.

Carl Eugen