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

Romain Beauxis toots at rastageeks.org
Tue Nov 30 15:23:25 EET 2021


* 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 at rastageeks.org>
---
libavdevice/avfoundation.m | 250 +++++++++++++++++++++----------------
1 file changed, 144 insertions(+), 106 deletions(-)

diff --git a/libavdevice/avfoundation.m b/libavdevice/avfoundation.m
index 0cd6e646d5..79c9207cfa 100644
--- a/libavdevice/avfoundation.m
+++ b/libavdevice/avfoundation.m
@@ -111,16 +111,10 @@

    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            bytes_per_sample;
+    AudioConverterRef audio_converter;

    enum AVPixelFormat pixel_format;

@@ -299,7 +293,10 @@ 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 +670,10 @@ 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 +691,95 @@ 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->bytes_per_sample = input_format->mBitsPerChannel >> 3;
+    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->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;
+        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 +1084,7 @@ 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 +1128,7 @@ 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);
                }
@@ -1105,82 +1142,83 @@ 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->bytes_per_sample);
+            int output_size = buffer_size;

-            if (ctx->audio_non_interleaved && block_buffer_size > ctx->audio_buffer_size) {
+            UInt32 size = sizeof(output_size);
+            ret = AudioConverterGetProperty(ctx->audio_converter, kAudioConverterPropertyCalculateOutputBufferSize, &size, &output_size);
+            if (ret != noErr) {
                unlock_frames(ctx);
-                return AVERROR_BUFFER_TOO_SMALL;
+                return AVERROR(EIO);
            }

-            if (av_new_packet(pkt, block_buffer_size) < 0) {
+            if (av_new_packet(pkt, output_size) < 0) {
                unlock_frames(ctx);
                return AVERROR(EIO);
            }

-            CMItemCount count;
-            CMSampleTimingInfo timing_info;
+            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);

-            if (CMSampleBufferGetOutputSampleTimingInfoArray(ctx->current_audio_frame, 1, &timing_info, &count) == noErr) {
-                AVRational timebase_q = av_make_q(1, timing_info.presentationTimeStamp.timescale);
-                pkt->pts = pkt->dts = av_rescale_q(timing_info.presentationTimeStamp.value, timebase_q, avf_time_base_q);
-            }
+                input_buffer->mNumberBuffers = ctx->audio_buffers;

-            pkt->stream_index  = ctx->audio_stream_index;
-            pkt->flags        |= AV_PKT_FLAG_KEY;
+                for (int c = 0; c < ctx->audio_buffers; c++) {
+                    input_buffer->mBuffers[c].mNumberChannels = 1;

-            if (ctx->audio_non_interleaved) {
-                int sample, c, shift, num_samples;
+                    ret = CMBlockBufferGetDataPointer(block_buffer, c * buffer_size, (size_t *)&input_buffer->mBuffers[c].mDataByteSize, NULL, (void *)&input_buffer->mBuffers[c].mData);

-                OSStatus ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size, ctx->audio_buffer);
-                if (ret != kCMBlockBufferNoErr) {
-                    unlock_frames(ctx);
-                    return AVERROR(EIO);
+                    if (ret != kCMBlockBufferNoErr) {
+                        av_free(input_buffer);
+                        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);                                                    \
-                }
+                AudioBufferList output_buffer = {
+                   .mNumberBuffers = 1,
+                   .mBuffers[0]    = {
+                       .mNumberChannels = ctx->audio_channels,
+                       .mDataByteSize   = pkt->size,
+                       .mData           = pkt->data
+                   }
+                };

-                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) {
+                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;
+            CMSampleTimingInfo timing_info;
+
+            if (CMSampleBufferGetOutputSampleTimingInfoArray(ctx->current_audio_frame, 1, &timing_info, &count) == noErr) {
+                AVRational timebase_q = av_make_q(1, timing_info.presentationTimeStamp.timescale);
+                pkt->pts = pkt->dts = av_rescale_q(timing_info.presentationTimeStamp.value, timebase_q, avf_time_base_q);
+            }
+
+            pkt->stream_index  = ctx->audio_stream_index;
+            pkt->flags        |= AV_PKT_FLAG_KEY;
+
            CFRelease(ctx->current_audio_frame);
            ctx->current_audio_frame = nil;
+
+            unlock_frames(ctx);
        } else {
            pkt->data = NULL;
            unlock_frames(ctx);
-- 
2.30.1 (Apple Git-130)



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