[FFmpeg-devel] [PATCH] avformat/dashdec: accept and relay CENC decryption key

[Gyan Doshi]

On 2022-05-14 04:08 pm, Steven Liu wrote:
> Gyan Doshi <ffmpeg at gyani.pro> 于2022年5月14日周六 17:18写道：
>> Allows to process CENC-encrypted media segments.
>> Option arg syntax is same as that for option decryption_key in MOV demuxer
>> ---
>>   doc/demuxers.texi     | 11 +++++++++++
>>   libavformat/dashdec.c |  5 +++++
>>   2 files changed, 16 insertions(+)
>>
>> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
>> index 238b8e03a8..c95a9ae594 100644
>> --- a/doc/demuxers.texi
>> +++ b/doc/demuxers.texi
>> @@ -274,6 +274,17 @@ which streams to actually receive.
>>   Each stream mirrors the @code{id} and @code{bandwidth} properties from the
>>   @code{<Representation>} as metadata keys named "id" and "variant_bitrate" respectively.
>>
>> + at subsection Options
>> +
>> +This demuxer accepts the following option:
>> +
>> + at table @option
>> +
>> + at item cenc_decryption_key
>> +16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption (CENC/AES-128 CTR; ISO/IEC 23001-7).
>> +
>> + at end table
>> +
>>   @section imf
>>
>>   Interoperable Master Format demuxer.
>> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
>> index 0b5ff5aeb9..0f66251354 100644
>> --- a/libavformat/dashdec.c
>> +++ b/libavformat/dashdec.c
>> @@ -150,6 +150,7 @@ typedef struct DASHContext {
>>       char *allowed_extensions;
>>       AVDictionary *avio_opts;
>>       int max_url_size;
>> +    char *cenc_decryption_key;
>>
>>       /* Flags for init section*/
>>       int is_init_section_common_video;
>> @@ -1893,6 +1894,9 @@ static int reopen_demux_for_component(AVFormatContext *s, struct representation
>>       pls->ctx->pb = &pls->pb.pub;
>>       pls->ctx->io_open  = nested_io_open;
>>
>> +    if (c->cenc_decryption_key)
>> +        av_dict_set(&in_fmt_opts, "decryption_key", c->cenc_decryption_key, AV_OPT_FLAG_DECODING_PARAM);
>> +
>>       // provide additional information from mpd if available
>>       ret = avformat_open_input(&pls->ctx, "", in_fmt, &in_fmt_opts); //pls->init_section->url
>>       av_dict_free(&in_fmt_opts);
>> @@ -2344,6 +2348,7 @@ static const AVOption dash_options[] = {
>>           OFFSET(allowed_extensions), AV_OPT_TYPE_STRING,
>>           {.str = "aac,m4a,m4s,m4v,mov,mp4,webm,ts"},
>>           INT_MIN, INT_MAX, FLAGS},
>> +    { "cenc_decryption_key", "Media decryption key (hex)", OFFSET(cenc_decryption_key), AV_OPT_TYPE_STRING, {.str = NULL}, INT_MIN, INT_MAX, .flags = FLAGS },
>>       {NULL}
>>   };
>>
>> --
>> 2.36.1
>>
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>
> LGTM

Pushed as 8b64d8d9aa7fede94ab531b7be3f73cd2f3c448c

Thanks,
Gyan