Re: [FFmpeg-devel] [PATCH] Make Immersive Audio Model optional for MOV demuxing

[James Almer]

On 4/2/2024 7:50 PM, Eugene Zemtsov via ffmpeg-devel wrote:
Is there anything I can do to get this path applied?
I can make iamfdec optional for mov demuxer in the same change if it's
something you're willing to do.

This change as is is not ok because CONFIG_IAMFDEC is always true when 
building the mov demuxer. It's a change that very clearly will depend on 
a custom config.h/mak as modified by projects using ffmpeg.

But yes, your suggestion is ok. Simpler way is probably how faan is 
handled in configure: Add a new iamf entry to SUBSYSTEM_LIST and make 
iamfdec and iamfenc depend on it. Also list the relevant --disable-iamf 
option to the output of configure --help, alongside --disable-faan and 
similar.


On Wed, Mar 27, 2024 at 5:43 PM Eugene Zemtsov <ezemt...@google.com> wrote:

Can you elaborate why you need this? In configure the mov demuxer
selects iamfdec, so it will always be present and compiled.

Chromium doesn't use Immersive Audio, but the code for handling it
bloats Android binaries,
that's why we disabled it.

I have a second patch that disables iamfdec by default for mov demuxer,
but I had a feeling that maintainers will be less inclined to accept
it and that's why I split it from this one.
I will still try to send it if this patch is accepted.


On Wed, Mar 27, 2024 at 4:59 PM James Almer <jamr...@gmail.com> wrote:

On 3/27/2024 8:55 PM, Eugene Zemtsov via ffmpeg-devel wrote:
From: Eugene Zemtsov <eug...@chromium.org>

Signed-off-by: Eugene Zemtsov <eug...@chromium.org>
---
   libavformat/mov.c | 15 ++++++++++++++-
   1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index c55778f3ef..662301bf67 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -839,6 +839,7 @@ static int mov_read_dac3(MOVContext *c, AVIOContext *pb, 
MOVAtom atom)
       return 0;
   }

+#if CONFIG_IAMFDEC
   static int mov_read_iacb(MOVContext *c, AVIOContext *pb, MOVAtom atom)
   {
       AVStream *st;
@@ -1015,6 +1016,7 @@ fail:

       return ret;
   }
+#endif

   static int mov_read_dec3(MOVContext *c, AVIOContext *pb, MOVAtom atom)
   {
@@ -4797,6 +4799,7 @@ static void fix_timescale(MOVContext *c, MOVStreamContext 
*sc)
       }
   }

+#if CONFIG_IAMFDEC
   static int mov_update_iamf_streams(MOVContext *c, const AVStream *st)
   {
       const MOVStreamContext *sc = st->priv_data;
@@ -4840,6 +4843,7 @@ static int mov_update_iamf_streams(MOVContext *c, const 
AVStream *st)

       return 0;
   }
+#endif

   static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
   {
@@ -4921,11 +4925,13 @@ static int mov_read_trak(MOVContext *c, AVIOContext 
*pb, MOVAtom atom)

       mov_build_index(c, st);

+#if CONFIG_IAMFDEC
       if (sc->iamf) {
           ret = mov_update_iamf_streams(c, st);
           if (ret < 0)
               return ret;
       }
+#endif

       if (sc->dref_id-1 < sc->drefs_count && sc->drefs[sc->dref_id-1].path) {
           MOVDref *dref = &sc->drefs[sc->dref_id - 1];
@@ -8457,7 +8463,9 @@ static const MOVParseTableEntry mov_default_parse_table[] 
= {
   { MKTAG('i','p','r','p'), mov_read_iprp },
   { MKTAG('i','i','n','f'), mov_read_iinf },
   { MKTAG('a','m','v','e'), mov_read_amve }, /* ambient viewing environment 
box */
+#if CONFIG_IAMFDEC
   { MKTAG('i','a','c','b'), mov_read_iacb },
+#endif
   { 0, NULL }
   };

@@ -8929,8 +8937,10 @@ static void mov_free_stream_context(AVFormatContext *s, 
AVStream *st)
       av_freep(&sc->coll);
       av_freep(&sc->ambient);

+#if CONFIG_IAMFDEC
       if (sc->iamf)
           ff_iamf_read_deinit(sc->iamf);
+#endif
       av_freep(&sc->iamf);
   }

@@ -9570,6 +9580,7 @@ static int mov_read_packet(AVFormatContext *s, AVPacket 
*pkt)

           if (st->codecpar->codec_id == AV_CODEC_ID_EIA_608 && sample->size > 
8)
               ret = get_eia608_packet(sc->pb, pkt, sample->size);
+#if CONFIG_IAMFDEC
           else if (sc->iamf) {
               int64_t pts, dts, pos, duration;
               int flags, size = sample->size;
@@ -9592,7 +9603,9 @@ static int mov_read_packet(AVFormatContext *s, AVPacket 
*pkt)
               }
               if (!ret)
                   return FFERROR_REDO;
-        } else
+        }
+#endif
+        else
               ret = av_get_packet(sc->pb, pkt, sample->size);
           if (ret < 0) {
               if (should_retry(sc->pb, ret)) {

Can you elaborate why you need this? In configure the mov demuxer
selects iamfdec, so it will always be present and compiled.
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--
Thanks,
Eugene Zemtsov.



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