[FFmpeg-devel] [PATCH v9 1/3] libavdevice/avfoundation.m: use AudioConvert, extend supported formats

* [FFmpeg-devel] [PATCH v9 1/3] libavdevice/avfoundation.m: use AudioConvert, extend supported formats
@ 2022-01-06 14:24 Romain Beauxis
  2022-01-14 12:57 ` Marvin Scholz
  0 siblings, 1 reply; 5+ messages in thread
From: Romain Beauxis @ 2022-01-06 14:24 UTC (permalink / raw)
  To: ffmpeg-devel; +Cc: thilo.borgmann, Aman Karmani, epirat07

* Implement support for AudioConverter
* Switch to AudioConverter's API to convert unsupported PCM
  formats (non-interleaved, non-packed) to supported formats
* Minimize data copy.

This fixes: https://trac.ffmpeg.org/ticket/9502

API ref:
https://developer.apple.com/documentation/audiotoolbox/audio_converter_services

Signed-off-by: Romain Beauxis <toots@rastageeks.org>
---
This is the first patch of a series of 3 that fix, cleanup and enhance the
avfoundation implementation for libavdevice.

These patches come from an actual user-facing application relying on
libavdevice’s implementation of avfoundation audio input. Without them,
Avfoundation is practically unusable as it will:
* Refuse to process certain specific audio input format that are actually
returned by the OS for some users (packed PCM audio)
* Drop audio frames, resulting in corrupted audio input. This might have been
unnoticed with video frames but this makes avfoundation essentially unusable
for audio.

The patches are now being included in our production build so they are tested
and usable in production.

Changelog for this patch:
* v2: None
* v3: None
* v4: None
* v5: Fix indentation/wrapping
* v6: None
* v7: Removed use of kAudioConverterPropertyCalculateOutputBufferSize
to calculate output buffer size. The calculation is trivial and this call was 
randomly failing for no reason
* v8: None
* v9: None

libavdevice/avfoundation.m | 255 +++++++++++++++++++++----------------
1 file changed, 145 insertions(+), 110 deletions(-)

diff --git a/libavdevice/avfoundation.m b/libavdevice/avfoundation.m
index 0cd6e646d5..738cd93375 100644
--- a/libavdevice/avfoundation.m
+++ b/libavdevice/avfoundation.m
@@ -111,16 +111,11 @@

    int             num_video_devices;

-    int             audio_channels;
-    int             audio_bits_per_sample;
-    int             audio_float;
-    int             audio_be;
-    int             audio_signed_integer;
-    int             audio_packed;
-    int             audio_non_interleaved;
-
-    int32_t         *audio_buffer;
-    int             audio_buffer_size;
+    UInt32            audio_buffers;
+    UInt32            audio_channels;
+    UInt32            input_bytes_per_sample;
+    UInt32            output_bytes_per_sample;
+    AudioConverterRef audio_converter;

    enum AVPixelFormat pixel_format;

@@ -299,7 +294,10 @@ static void destroy_context(AVFContext* ctx)
    ctx->avf_delegate    = NULL;
    ctx->avf_audio_delegate = NULL;

-    av_freep(&ctx->audio_buffer);
+    if (ctx->audio_converter) {
+      AudioConverterDispose(ctx->audio_converter);
+      ctx->audio_converter = NULL;
+    }

    pthread_mutex_destroy(&ctx->frame_lock);

@@ -673,6 +671,10 @@ static int get_audio_config(AVFormatContext *s)
    AVFContext *ctx = (AVFContext*)s->priv_data;
    CMFormatDescriptionRef format_desc;
    AVStream* stream = avformat_new_stream(s, NULL);
+    AudioStreamBasicDescription output_format = {0};
+    int audio_bits_per_sample, audio_float, audio_be;
+    int audio_signed_integer, audio_packed, audio_non_interleaved;
+    int must_convert = 0;

    if (!stream) {
        return 1;
@@ -690,60 +692,97 @@ static int get_audio_config(AVFormatContext *s)
    avpriv_set_pts_info(stream, 64, 1, avf_time_base);

    format_desc = CMSampleBufferGetFormatDescription(ctx->current_audio_frame);
-    const AudioStreamBasicDescription *basic_desc = CMAudioFormatDescriptionGetStreamBasicDescription(format_desc);
+    const AudioStreamBasicDescription *input_format = CMAudioFormatDescriptionGetStreamBasicDescription(format_desc);

-    if (!basic_desc) {
+    if (!input_format) {
        unlock_frames(ctx);
        av_log(s, AV_LOG_ERROR, "audio format not available\n");
        return 1;
    }

+    if (input_format->mFormatID != kAudioFormatLinearPCM) {
+        unlock_frames(ctx);
+        av_log(s, AV_LOG_ERROR, "only PCM audio format are supported at the moment\n");
+        return 1;
+    }
+
    stream->codecpar->codec_type     = AVMEDIA_TYPE_AUDIO;
-    stream->codecpar->sample_rate    = basic_desc->mSampleRate;
-    stream->codecpar->channels       = basic_desc->mChannelsPerFrame;
+    stream->codecpar->sample_rate    = input_format->mSampleRate;
+    stream->codecpar->channels       = input_format->mChannelsPerFrame;
    stream->codecpar->channel_layout = av_get_default_channel_layout(stream->codecpar->channels);

-    ctx->audio_channels        = basic_desc->mChannelsPerFrame;
-    ctx->audio_bits_per_sample = basic_desc->mBitsPerChannel;
-    ctx->audio_float           = basic_desc->mFormatFlags & kAudioFormatFlagIsFloat;
-    ctx->audio_be              = basic_desc->mFormatFlags & kAudioFormatFlagIsBigEndian;
-    ctx->audio_signed_integer  = basic_desc->mFormatFlags & kAudioFormatFlagIsSignedInteger;
-    ctx->audio_packed          = basic_desc->mFormatFlags & kAudioFormatFlagIsPacked;
-    ctx->audio_non_interleaved = basic_desc->mFormatFlags & kAudioFormatFlagIsNonInterleaved;
-
-    if (basic_desc->mFormatID == kAudioFormatLinearPCM &&
-        ctx->audio_float &&
-        ctx->audio_bits_per_sample == 32 &&
-        ctx->audio_packed) {
-        stream->codecpar->codec_id = ctx->audio_be ? AV_CODEC_ID_PCM_F32BE : AV_CODEC_ID_PCM_F32LE;
-    } else if (basic_desc->mFormatID == kAudioFormatLinearPCM &&
-        ctx->audio_signed_integer &&
-        ctx->audio_bits_per_sample == 16 &&
-        ctx->audio_packed) {
-        stream->codecpar->codec_id = ctx->audio_be ? AV_CODEC_ID_PCM_S16BE : AV_CODEC_ID_PCM_S16LE;
-    } else if (basic_desc->mFormatID == kAudioFormatLinearPCM &&
-        ctx->audio_signed_integer &&
-        ctx->audio_bits_per_sample == 24 &&
-        ctx->audio_packed) {
-        stream->codecpar->codec_id = ctx->audio_be ? AV_CODEC_ID_PCM_S24BE : AV_CODEC_ID_PCM_S24LE;
-    } else if (basic_desc->mFormatID == kAudioFormatLinearPCM &&
-        ctx->audio_signed_integer &&
-        ctx->audio_bits_per_sample == 32 &&
-        ctx->audio_packed) {
-        stream->codecpar->codec_id = ctx->audio_be ? AV_CODEC_ID_PCM_S32BE : AV_CODEC_ID_PCM_S32LE;
+    audio_bits_per_sample = input_format->mBitsPerChannel;
+    audio_float           = input_format->mFormatFlags & kAudioFormatFlagIsFloat;
+    audio_be              = input_format->mFormatFlags & kAudioFormatFlagIsBigEndian;
+    audio_signed_integer  = input_format->mFormatFlags & kAudioFormatFlagIsSignedInteger;
+    audio_packed          = input_format->mFormatFlags & kAudioFormatFlagIsPacked;
+    audio_non_interleaved = input_format->mFormatFlags & kAudioFormatFlagIsNonInterleaved;
+
+    ctx->input_bytes_per_sample  = input_format->mBitsPerChannel >> 3;
+    ctx->output_bytes_per_sample = ctx->input_bytes_per_sample;
+    ctx->audio_channels          = input_format->mChannelsPerFrame;
+
+    if (audio_non_interleaved) {
+        ctx->audio_buffers = input_format->mChannelsPerFrame;
    } else {
-        unlock_frames(ctx);
-        av_log(s, AV_LOG_ERROR, "audio format is not supported\n");
-        return 1;
+        ctx->audio_buffers = 1;
+    }
+
+    if (audio_non_interleaved || !audio_packed) {
+      must_convert = 1;
+    }
+
+    output_format.mBitsPerChannel   = input_format->mBitsPerChannel;
+    output_format.mChannelsPerFrame = ctx->audio_channels;
+    output_format.mFramesPerPacket  = 1;
+    output_format.mBytesPerFrame    = output_format.mChannelsPerFrame * ctx->input_bytes_per_sample;
+    output_format.mBytesPerPacket   = output_format.mFramesPerPacket * output_format.mBytesPerFrame;
+    output_format.mFormatFlags      = kAudioFormatFlagIsPacked | audio_be;
+    output_format.mFormatID         = kAudioFormatLinearPCM;
+    output_format.mReserved         = 0;
+    output_format.mSampleRate       = input_format->mSampleRate;
+
+    if (audio_float &&
+        audio_bits_per_sample == 32) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_F32BE : AV_CODEC_ID_PCM_F32LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsFloat;
+    } else if (audio_float &&
+        audio_bits_per_sample == 64) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_F64BE : AV_CODEC_ID_PCM_F64LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsFloat;
+    } else if (audio_signed_integer &&
+        audio_bits_per_sample == 8) {
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S8;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+    } else if (audio_signed_integer &&
+        audio_bits_per_sample == 16) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_S16BE : AV_CODEC_ID_PCM_S16LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+    } else if (audio_signed_integer &&
+        audio_bits_per_sample == 24) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_S24BE : AV_CODEC_ID_PCM_S24LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+    } else if (audio_signed_integer &&
+        audio_bits_per_sample == 32) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_S32BE : AV_CODEC_ID_PCM_S32LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+    } else if (audio_signed_integer &&
+        audio_bits_per_sample == 64) {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_S64BE : AV_CODEC_ID_PCM_S64LE;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+    } else {
+        stream->codecpar->codec_id = audio_be ? AV_CODEC_ID_PCM_S32BE : AV_CODEC_ID_PCM_S32LE;
+        ctx->output_bytes_per_sample = 4;
+        output_format.mBitsPerChannel = 32;
+        output_format.mFormatFlags |= kAudioFormatFlagIsSignedInteger;
+        must_convert = 1;
    }

-    if (ctx->audio_non_interleaved) {
-        CMBlockBufferRef block_buffer = CMSampleBufferGetDataBuffer(ctx->current_audio_frame);
-        ctx->audio_buffer_size        = CMBlockBufferGetDataLength(block_buffer);
-        ctx->audio_buffer             = av_malloc(ctx->audio_buffer_size);
-        if (!ctx->audio_buffer) {
+    if (must_convert) {
+        OSStatus ret = AudioConverterNew(input_format, &output_format, &ctx->audio_converter);
+        if (ret != noErr) {
            unlock_frames(ctx);
-            av_log(s, AV_LOG_ERROR, "error allocating audio buffer\n");
+            av_log(s, AV_LOG_ERROR, "Error while allocating audio converter\n");
            return 1;
        }
    }
@@ -1048,6 +1087,7 @@ static int copy_cvpixelbuffer(AVFormatContext *s,

static int avf_read_packet(AVFormatContext *s, AVPacket *pkt)
{
+    OSStatus ret;
    AVFContext* ctx = (AVFContext*)s->priv_data;

    do {
@@ -1091,7 +1131,7 @@ static int avf_read_packet(AVFormatContext *s, AVPacket *pkt)
                status = copy_cvpixelbuffer(s, image_buffer, pkt);
            } else {
                status = 0;
-                OSStatus ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, pkt->data);
+                ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, pkt->data);
                if (ret != kCMBlockBufferNoErr) {
                    status = AVERROR(EIO);
                }
@@ -1105,21 +1145,60 @@ static int avf_read_packet(AVFormatContext *s, AVPacket *pkt)
            }
        } else if (ctx->current_audio_frame != nil) {
            CMBlockBufferRef block_buffer = CMSampleBufferGetDataBuffer(ctx->current_audio_frame);
-            int block_buffer_size         = CMBlockBufferGetDataLength(block_buffer);

-            if (!block_buffer || !block_buffer_size) {
-                unlock_frames(ctx);
-                return AVERROR(EIO);
-            }
+            size_t input_size = CMBlockBufferGetDataLength(block_buffer);
+            int buffer_size = input_size / ctx->audio_buffers;
+            int nb_samples = input_size / (ctx->audio_channels * ctx->input_bytes_per_sample);
+            int output_size = nb_samples * ctx->output_bytes_per_sample * ctx->audio_channels;

-            if (ctx->audio_non_interleaved && block_buffer_size > ctx->audio_buffer_size) {
-                unlock_frames(ctx);
-                return AVERROR_BUFFER_TOO_SMALL;
+            status = av_new_packet(pkt, output_size);
+            if (status < 0) {
+                CFRelease(audio_frame);
+                return status;
            }

-            if (av_new_packet(pkt, block_buffer_size) < 0) {
-                unlock_frames(ctx);
-                return AVERROR(EIO);
+            if (ctx->audio_converter) {
+                size_t input_buffer_size = offsetof(AudioBufferList, mBuffers[0]) + (sizeof(AudioBuffer) * ctx->audio_buffers);
+                AudioBufferList *input_buffer = av_malloc(input_buffer_size);
+
+                input_buffer->mNumberBuffers = ctx->audio_buffers;
+
+                for (int c = 0; c < ctx->audio_buffers; c++) {
+                    input_buffer->mBuffers[c].mNumberChannels = 1;
+
+                    ret = CMBlockBufferGetDataPointer(block_buffer, c * buffer_size, (size_t *)&input_buffer->mBuffers[c].mDataByteSize, NULL, (void *)&input_buffer->mBuffers[c].mData);
+
+                    if (ret != kCMBlockBufferNoErr) {
+                        av_free(input_buffer);
+                        unlock_frames(ctx);
+                        return AVERROR(EIO);
+                    }
+                }
+
+                AudioBufferList output_buffer = {
+                   .mNumberBuffers = 1,
+                   .mBuffers[0]    = {
+                       .mNumberChannels = ctx->audio_channels,
+                       .mDataByteSize   = pkt->size,
+                       .mData           = pkt->data
+                   }
+                };
+
+                ret = AudioConverterConvertComplexBuffer(ctx->audio_converter, nb_samples, input_buffer, &output_buffer);
+                av_free(input_buffer);
+
+                if (ret != noErr) {
+                    unlock_frames(ctx);
+                    return AVERROR(EIO);
+                }
+
+                pkt->size = output_buffer.mBuffers[0].mDataByteSize;
+            } else {
+                 ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, pkt->data);
+                 if (ret != kCMBlockBufferNoErr) {
+                     unlock_frames(ctx);
+                     return AVERROR(EIO);
+                 }
            }

            CMItemCount count;
@@ -1133,54 +1212,10 @@ static int avf_read_packet(AVFormatContext *s, AVPacket *pkt)
            pkt->stream_index  = ctx->audio_stream_index;
            pkt->flags        |= AV_PKT_FLAG_KEY;

-            if (ctx->audio_non_interleaved) {
-                int sample, c, shift, num_samples;
-
-                OSStatus ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, ctx->audio_buffer);
-                if (ret != kCMBlockBufferNoErr) {
-                    unlock_frames(ctx);
-                    return AVERROR(EIO);
-                }
-
-                num_samples = pkt->size / (ctx->audio_channels * (ctx->audio_bits_per_sample >> 3));
-
-                // transform decoded frame into output format
-                #define INTERLEAVE_OUTPUT(bps)                                         \
-                {                                                                      \
-                    int##bps##_t **src;                                                \
-                    int##bps##_t *dest;                                                \
-                    src = av_malloc(ctx->audio_channels * sizeof(int##bps##_t*));      \
-                    if (!src) {                                                        \
-                        unlock_frames(ctx);                                            \
-                        return AVERROR(EIO);                                           \
-                    }                                                                  \
-                                                                                       \
-                    for (c = 0; c < ctx->audio_channels; c++) {                        \
-                        src[c] = ((int##bps##_t*)ctx->audio_buffer) + c * num_samples; \
-                    }                                                                  \
-                    dest  = (int##bps##_t*)pkt->data;                                  \
-                    shift = bps - ctx->audio_bits_per_sample;                          \
-                    for (sample = 0; sample < num_samples; sample++)                   \
-                        for (c = 0; c < ctx->audio_channels; c++)                      \
-                            *dest++ = src[c][sample] << shift;                         \
-                    av_freep(&src);                                                    \
-                }
-
-                if (ctx->audio_bits_per_sample <= 16) {
-                    INTERLEAVE_OUTPUT(16)
-                } else {
-                    INTERLEAVE_OUTPUT(32)
-                }
-            } else {
-                OSStatus ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, pkt->data);
-                if (ret != kCMBlockBufferNoErr) {
-                    unlock_frames(ctx);
-                    return AVERROR(EIO);
-                }
-            }
-
            CFRelease(ctx->current_audio_frame);
            ctx->current_audio_frame = nil;
+
+            unlock_frames(ctx);
        } else {
            pkt->data = NULL;
            unlock_frames(ctx);
-- 
2.32.0 (Apple Git-132)

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

^ permalink raw reply	[flat|nested] 5+ messages in thread