[FFmpeg-devel] [PATCH] Add support for demuxing the combined TrueHD/AC3 tracks in Blu-Ray m2ts files

[Ian Caulfield]

2009/9/29 Baptiste Coudurier <baptiste.coudurier at gmail.com>:
> On 9/29/09 2:30 AM, Ian Caulfield wrote:
>>
>> This patch allows the combined TrueHD/AC3 tracks on Blu-Ray discs to be
>> demuxed as two separate streams.
>>
>> Updated version that doesn't fudge the stream id of the AC3 track - both
>> ?streams will have the PID as the stream id.
>>
>
> I also find this very ugly, but I guess we do not have any other way of
> doing it.
>
> I'm fine with the patch, though I think I like better sub_st and sub_pes
> instead of st2 and pes2, if you are ok with that.

Yeah - adding 2 was just the first thing that came to mind :)

>> [...]
>>
>>
>> @@ -584,6 +587,27 @@ static AVStream *new_pes_av_stream(PESContext *pes,
>> uint32_t prog_reg_desc, uint
>> ? ? ? ? ?}
>> ? ? ?}
>>
>> + ? ?// HDMV TrueHD streams also contain an AC3 coded version of the
>> + ? ?// audio track - add a second stream for this
>> + ? ?if (prog_reg_desc == AV_RL32("HDMV")&& ?pes->stream_type == 0x83) {
>> + ? ? ? ?// priv_data cannot be shered between streams
>> + ? ? ? ?PESContext *pes2 = av_malloc(sizeof(PESContext));
>> + ? ? ? ?memcpy(pes2, pes, sizeof(PESContext));
>
> sizeof(*pes2);
>
> And put the code under the first if (prog_reg_desc == AV_RL32("HDMV"))

Fixed

>> + ? ? ? ?if (pes2) {
>> + ? ? ? ? ? ?AVStream *st2 = av_new_stream(pes->stream, pes2->pid);
>> +
>
> pes->pid seems more logicical
>
>> + ? ? ? ? ? ?if (st2) {
>> + ? ? ? ? ? ? ? ?av_set_pts_info(st2, 33, 1, 90000);
>> + ? ? ? ? ? ? ? ?st2->priv_data = pes2;
>> + ? ? ? ? ? ? ? ?st2->codec->codec_type = CODEC_TYPE_AUDIO;
>> + ? ? ? ? ? ? ? ?st2->codec->codec_id ? = CODEC_ID_AC3;
>> + ? ? ? ? ? ? ? ?st2->need_parsing = AVSTREAM_PARSE_FULL;
>> + ? ? ? ? ? ? ? ?pes2->st2 = pes->st2 = st2;
>> + ? ? ? ? ? ?} else
>> + ? ? ? ? ? ? ? ?av_free(pes2);
>
> Can we continue with pes->st2 not set but pes->st set ?
> If not pes->st should be freed also.
>
> if (!st2) {
> ? ?av_free(pes2);
> ? ?return NULL;
> }
>
> Looks better IMHO.

Yeah, I agree - if there's an error it makes sense to pass it up
instead of hiding it, too...

>> [...]
>>
>> @@ -592,7 +616,7 @@ static void pmt_cb(MpegTSFilter *filter, const
>> ? ? ? MpegTSContext *ts = filter->u.section_filter.opaque;
>> ? ? ? SectionHeader h1, *h =&h1;
>> ? ? ? PESContext *pes;
>> - ? ?AVStream *st;
>> + ? ?AVStream *st, *st2;
>> ? ? ? const uint8_t *p, *p_end, *desc_list_end, *desc_end;
>> ? ? ? int program_info_length, pcr_pid, pid, stream_type;
>> ? ? ? int desc_list_len, desc_len, desc_tag;
>> @@ -730,6 +754,14 @@ static void pmt_cb(MpegTSFilter *filter, const
>> ? ? ? ? ? ? ? ? ? break;
>> ? ? ? ? ? ? ? }
>> ? ? ? ? ? ? ? p = desc_end;
>> +
>> + ? ? ? ? ? ?if (prog_reg_desc == AV_RL32("HDMV")&& ?stream_type == 0
>> + ? ? ? ? ? ? ? ?st2 = pes->st2;
>> + ? ? ? ? ? ? ? ?if (st2) {
>> + ? ? ? ? ? ? ? ? ? ?av_program_add_stream_index(ts->stream, h->id, s
>> + ? ? ? ? ? ? ? ? ? ?st2->codec->codec_tag = st->codec->codec_tag;
>> + ? ? ? ? ? ? ? ?}
>> + ? ? ? ? ? ?}
>> ? ? ? ? ? }
>> ? ? ? ? ? p = desc_list_end;
>
> Is st2 variable really needed here ?

No - it was originally there for symmetry with st, but that's used
differently, so the reasoning falls down. Removed.

Updated patch addressing comments attached.

Ian
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