[FFmpeg-devel] [PATCH 1/2] mpegts: add all stream languages into metadata

[Ronald S. Bultje]

Hi,

On Mon, Mar 7, 2011 at 2:59 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
> On 07.03.2011 21:50, Ronald S. Bultje wrote:
>> 2011/3/7 M?ns Rullg?rd <mans at mansr.com>:
>>> "Ronald S. Bultje" <rsbultje at gmail.com> writes:
>>>> On Thu, Feb 17, 2011 at 10:26 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>> This is used at least on some older DVB broadcasts for dual-mono audio
>>>>> tracks.
>>>>> ---
>>>>>
>>>>> Here goes the patchset without the channelX/language stuff.
>>>>> I also changed the language separator from '+' from ',', but I'm open
>>>>> to bikeshedding.
>>>>>
>>>>> ?libavformat/mpegts.c | ? 18 ++++++++++++------
>>>>> ?1 files changed, 12 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
>>>>> index abb6f08..c7e4fe3 100644
>>>>> --- a/libavformat/mpegts.c
>>>>> +++ b/libavformat/mpegts.c
>>>>> @@ -890,7 +890,8 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
>>>>> ?{
>>>>> ? ? const uint8_t *desc_end;
>>>>> ? ? int desc_len, desc_tag;
>>>>> - ? ?char language[4];
>>>>> + ? ?char language[252];
>>>>> + ? ?int i;
>>>>>
>>>>> ? ? desc_tag = get8(pp, desc_list_end);
>>>>> ? ? if (desc_tag < 0)
>>>>> @@ -949,16 +950,21 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
>>>>> ? ? ? ? av_metadata_set2(&st->metadata, "language", language, 0);
>>>>> ? ? ? ? break;
>>>>> ? ? case 0x0a: /* ISO 639 language descriptor */
>>>>> - ? ? ? ?language[0] = get8(pp, desc_end);
>>>>> - ? ? ? ?language[1] = get8(pp, desc_end);
>>>>> - ? ? ? ?language[2] = get8(pp, desc_end);
>>>>> - ? ? ? ?language[3] = 0;
>>>>> - ? ? ? ?av_metadata_set2(&st->metadata, "language", language, 0);
>>>>> + ? ? ? ?for (i = 0; i + 4 <= desc_len; i += 4) {
>>>>> + ? ? ? ? ? ?language[i + 0] = get8(pp, desc_end);
>>>>> + ? ? ? ? ? ?language[i + 1] = get8(pp, desc_end);
>>>>> + ? ? ? ? ? ?language[i + 2] = get8(pp, desc_end);
>>>>> + ? ? ? ? ? ?language[i + 3] = ',';
>>>>> ? ? ? ? switch (get8(pp, desc_end)) {
>>>>> ? ? ? ? ? ? case 0x01: st->disposition |= AV_DISPOSITION_CLEAN_EFFECTS; break;
>>>>> ? ? ? ? ? ? case 0x02: st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED; break;
>>>>> ? ? ? ? ? ? case 0x03: st->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED; break;
>>>>> ? ? ? ? }
>>>>> + ? ? ? ?}
>>>>> + ? ? ? ?if (i) {
>>>>> + ? ? ? ? ? ?language[i - 1] = 0;
>>>>> + ? ? ? ? ? ?av_metadata_set2(&st->metadata, "language", language, 0);
>>>>> + ? ? ? ?}
>>>>
>>>> if language[] is 252 bytes, can this overflow? There's no checks for i
>>>> being under 252.
>>>
>>> desc_len is an 8-bit field in the stream.
>>
>> So shouldn't language[] be 256 bytes at least then?
>
> Maximum value of a 8-bit field is 255, and in 255 bytes there can only
> be 63 4-byte tags, which means 63 three-letter codes plus commas plus
> null byte, 63*3 + 62 + 1 = 252.

Got it, queued then.

Ronald