[FFmpeg-devel] [PATCH] avformat/isom: allow ISO 639 codes for mov
Baptiste Coudurier
baptiste.coudurier at gmail.com
Wed Jul 8 03:21:19 EEST 2020
Hey Yongle,
> On Jul 7, 2020, at 10:41 AM, Yongle Lin <yongle.lin.94 at gmail.com> wrote:
>
> On Mon, Jul 6, 2020 at 3:23 PM Baptiste Coudurier <
> baptiste.coudurier at gmail.com> wrote:
>
>> Hi Yongle, I hope you are doing well
>>
>>> On Jul 6, 2020, at 11:04 AM, Yongle Lin <yongle.lin.94 at gmail.com> wrote:
>>>
>>> On Fri, Jun 19, 2020 at 5:11 PM Yongle Lin <yongle.lin.94 at gmail.com
>> <mailto:yongle.lin.94 at gmail.com>> wrote:
>>>
>>>> Allow ISO 639 language codes for text tracks in mov format when
>>>> strictness is set to experimental
>>>> ---
>>>> libavformat/isom.c | 9 +++++++--
>>>> libavformat/isom.h | 2 +-
>>>> libavformat/movenc.c | 6 +++---
>>>> tests/fate/mov.mak | 3 +++
>>>> tests/ref/fate/mov-iso639-lang | 4 ++++
>>>> 5 files changed, 18 insertions(+), 6 deletions(-)
>>>> create mode 100644 tests/ref/fate/mov-iso639-lang
>>>>
>>>> diff --git a/libavformat/isom.c b/libavformat/isom.c
>>>> index 44c7b13038..de20ea8d8b 100644
>>>> --- a/libavformat/isom.c
>>>> +++ b/libavformat/isom.c
>>>> @@ -416,7 +416,7 @@ static const char mov_mdhd_language_map[][4] = {
>>>> "cat", "lat", "que", "grn", "aym", "tat", "uig", "dzo", "jav"
>>>> };
>>>>
>>>> -int ff_mov_iso639_to_lang(const char lang[4], int mp4)
>>>> +int ff_mov_iso639_to_lang(const char lang[4], int mp4, int
>>>> strict_std_compliance)
>>>> {
>>>> int i, code = 0;
>>>>
>>>> @@ -426,8 +426,13 @@ int ff_mov_iso639_to_lang(const char lang[4], int
>> mp4)
>>>> return i;
>>>> }
>>>> /* XXX:can we do that in mov too? */
>>>> - if (!mp4)
>>>> + if (!mp4 && (strict_std_compliance != FF_COMPLIANCE_EXPERIMENTAL ||
>>>> !strcmp(lang, "und"))) {
>>>> + if (strcmp(lang, "und"))
>>>> + av_log(NULL, AV_LOG_WARNING, "Non macintosh language is
>>>> discarded for mov\n");
>>>> return -1;
>>>> + }
>>>> + if (!mp4)
>>>> + av_log(NULL, AV_LOG_WARNING, "Experimental behavior: enable iso
>>>> 639 language in mov\n");
>>>> /* handle undefined as such */
>>>> if (lang[0] == '\0')
>>>> lang = "und";
>>>> diff --git a/libavformat/isom.h b/libavformat/isom.h
>>>> index 41a9c64c11..9d018ebf1f 100644
>>>> --- a/libavformat/isom.h
>>>> +++ b/libavformat/isom.h
>>>> @@ -43,7 +43,7 @@ extern const AVCodecTag ff_codec_movaudio_tags[];
>>>> extern const AVCodecTag ff_codec_movsubtitle_tags[];
>>>> extern const AVCodecTag ff_codec_movdata_tags[];
>>>>
>>>> -int ff_mov_iso639_to_lang(const char lang[4], int mp4);
>>>> +int ff_mov_iso639_to_lang(const char lang[4], int mp4, int
>>>> strict_std_compliance);
>>>> int ff_mov_lang_to_iso639(unsigned code, char to[4]);
>>>>
>>>> struct AVAESCTR;
>>>> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
>>>> index 520aaafb74..4d7a98245e 100644
>>>> --- a/libavformat/movenc.c
>>>> +++ b/libavformat/movenc.c
>>>> @@ -3429,7 +3429,7 @@ static int mov_write_string_data_tag(AVIOContext
>>>> *pb, const char *data, int lang
>>>> return size;
>>>> } else {
>>>> if (!lang)
>>>> - lang = ff_mov_iso639_to_lang("und", 1);
>>>> + lang = ff_mov_iso639_to_lang("und", 1,
>> FF_COMPLIANCE_NORMAL);
>>>> avio_wb16(pb, strlen(data)); /* string length */
>>>> avio_wb16(pb, lang);
>>>> avio_write(pb, data, strlen(data));
>>>> @@ -3468,7 +3468,7 @@ static AVDictionaryEntry
>>>> *get_metadata_lang(AVFormatContext *s,
>>>> while ((t2 = av_dict_get(s->metadata, tag2, t2,
>>>> AV_DICT_IGNORE_SUFFIX))) {
>>>> len2 = strlen(t2->key);
>>>> if (len2 == len + 4 && !strcmp(t->value, t2->value)
>>>> - && (l = ff_mov_iso639_to_lang(&t2->key[len2 - 3], 1)) >=
>> 0) {
>>>> + && (l = ff_mov_iso639_to_lang(&t2->key[len2 - 3], 1,
>>>> s->strict_std_compliance)) >= 0) {
>>>> *lang = l;
>>>> return t;
>>>> }
>>>> @@ -6445,7 +6445,7 @@ static int mov_init(AVFormatContext *s)
>>>>
>>>> track->st = st;
>>>> track->par = st->codecpar;
>>>> - track->language = ff_mov_iso639_to_lang(lang?lang->value:"und",
>>>> mov->mode!=MODE_MOV);
>>>> + track->language = ff_mov_iso639_to_lang(lang?lang->value:"und",
>>>> mov->mode!=MODE_MOV, s->strict_std_compliance);
>>>> if (track->language < 0)
>>>> track->language = 32767; // Unspecified Macintosh language
>>>> code
>>>> track->mode = mov->mode;
>>>> diff --git a/tests/fate/mov.mak b/tests/fate/mov.mak
>>>> index 7a721d7c95..a85cc1a07d 100644
>>>> --- a/tests/fate/mov.mak
>>>> +++ b/tests/fate/mov.mak
>>>> @@ -29,6 +29,7 @@ FATE_MOV_FFPROBE = fate-mov-neg-firstpts-discard \
>>>> fate-mov-guess-delay-2 \
>>>> fate-mov-guess-delay-3 \
>>>> fate-mov-mp4-with-mov-in24-ver \
>>>> + fate-mov-iso639-lang \
>>>>
>>>> FATE_MOV_FASTSTART = fate-mov-faststart-4gb-overflow \
>>>>
>>>> @@ -124,3 +125,5 @@ fate-mov-faststart-4gb-overflow: CMP = oneline
>>>> fate-mov-faststart-4gb-overflow: REF = bc875921f151871e787c4b4023269b29
>>>>
>>>> fate-mov-mp4-with-mov-in24-ver: CMD = run ffprobe$(PROGSSUF)$(EXESUF)
>>>> -show_entries stream=codec_name -select_streams 1
>>>> $(TARGET_SAMPLES)/mov/mp4-with-mov-in24-ver.mp4
>>>> +
>>>> +fate-mov-iso639-lang: CMD = ffmpeg$(PROGSSUF)$(EXESUF) -f lavfi -i
>>>> sine=frequency=1000:duration=15 -strict experimental -metadata:s:a:0
>>>> language=deu -y $(TARGET_PATH)/metadata.mov; run ffprobe -show_entries
>>>> stream=index:stream_tags=language $(TARGET_PATH)/metadata.mov; rm
>>>> metadata.mov
>>>> diff --git a/tests/ref/fate/mov-iso639-lang
>>>> b/tests/ref/fate/mov-iso639-lang
>>>> new file mode 100644
>>>> index 0000000000..6d1f61169d
>>>> --- /dev/null
>>>> +++ b/tests/ref/fate/mov-iso639-lang
>>>> @@ -0,0 +1,4 @@
>>>> +[STREAM]
>>>> +index=0
>>>> +TAG:language=deu
>>>> +[/STREAM]
>>>> --
>>>> 2.27.0.111.gc72c7da667-goog
>>>>
>>>> Dear FFmpeg Developers,
>>>
>>> Could you please review this patch when you have time. Thanks.
>>>
>>> Best,
>>> Yongle
>>
>>
>> Is it allowed by an official spec ? What would be the reason to use these
>> codes in mov ?
>>
>> Thanks a lot!
>>
>> —
>> Baptiste
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>> ffmpeg-devel at ffmpeg.org
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>>
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>
>
> Hi Baptiste,
>
> Thank you for your email. Basically, ISO language can be used only for user
> data text in a QuickTime file. All other elements including text tracks
> must be specified using Macintosh language codes. But it's valid to have
> ISO codes for text tracks of mov. So this patch allows ISO 639 codes for
> mov files. For example, "-metadata language:s:0 language=deu" currently
> drops the language information. I also added a sample FATE test you can
> check.
"Note: ISO language codes cannot be used for all elements of a QuickTime file. Currently, ISO language codes can be used only for user data text. All other elements, including text tracks, must be specified using Macintosh language codes.”
I think “user data text” is the user data contained in “meta” boxes. I’m not sure this patch actually implements that.
Thanks!
—
Baptiste Coudurier
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