* Use a CMSimpleQueueEnqueue with maximum length to queue and process incoming
audio and video frames.
* Log avfoundation errors.
* Use AVERROR_EXTERNAL instead of AVERROR(EIO) in avfoundation errors.
Signed-off-by: Romain Beauxis <to...@rastageeks.org>
—
This is the second 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.
This patch fixes the concurrency model. Avfoundation runs its own
producing thread to send produced frames and ffmpeg runs its own thread
to consume them.
The existing implementation stores the last transmitted frame and uses a
mutex to avoid concurrent access. However, this leads to situations
where upcoming frames can be dropped if the ffmpeg thread is acessing
the latest frame. This happens even when the thread would otherwise
catch up and process frames fast enought.
This patches changes this implementation to use a buffer queue with a
max queue length and encapsulated thread-safety. This greatly simplifies
the logic of the calling code and gives the consuming thread a chance to
process all frames concurrently to the producing thread while avoiding
memory leaks.
Changes:
v2: None
v3: Switched queue implementation to CMSimpleQueue
v4: None
v5: Fix indentation/wrapping
v6: Fix audio/video frame queue cleanup logic
v7: Enhance avfoundation error reporting: add human-readable description,
use AVERROR_EXTERNAL instead of AVERROR(EIO)
libavdevice/avfoundation.m | 196 ++++++++++++++++++-------------------
1 file changed, 96 insertions(+), 100 deletions(-)
diff --git a/libavdevice/avfoundation.m b/libavdevice/avfoundation.m
index 738cd93375..c740745fce 100644
--- a/libavdevice/avfoundation.m
+++ b/libavdevice/avfoundation.m
@@ -26,7 +26,7 @@
*/
#import <AVFoundation/AVFoundation.h>
-#include <pthread.h>
+#import <CoreMedia/CoreMedia.h>
#include "libavutil/channel_layout.h"
#include "libavutil/pixdesc.h"
@@ -39,6 +39,11 @@
#include "libavutil/imgutils.h"
#include "avdevice.h"
+#define av_log_avfoundation_error(str, err) \
+ av_log(s, AV_LOG_ERROR, "Avfoundation: %s, %s\n", str, \
+ [[[NSError errorWithDomain:NSOSStatusErrorDomain code:err userInfo:nil]
localizedDescription] UTF8String] \
+ )
+
static const int avf_time_base = 1000000;
static const AVRational avf_time_base_q = {
@@ -80,13 +85,12 @@
{ AV_PIX_FMT_NONE, 0 }
};
+#define MAX_QUEUED_FRAMES 10
+
typedef struct
{
AVClass* class;
- int frames_captured;
- int audio_frames_captured;
- pthread_mutex_t frame_lock;
id avf_delegate;
id avf_audio_delegate;
@@ -122,8 +126,8 @@
AVCaptureSession *capture_session;
AVCaptureVideoDataOutput *video_output;
AVCaptureAudioDataOutput *audio_output;
- CMSampleBufferRef current_frame;
- CMSampleBufferRef current_audio_frame;
+ CMSimpleQueueRef audio_frames_queue;
+ CMSimpleQueueRef video_frames_queue;
AVCaptureDevice *observed_device;
#if !TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
@@ -132,16 +136,6 @@
int observed_quit;
} AVFContext;
-static void lock_frames(AVFContext* ctx)
-{
- pthread_mutex_lock(&ctx->frame_lock);
-}
-
-static void unlock_frames(AVFContext* ctx)
-{
- pthread_mutex_unlock(&ctx->frame_lock);
-}
-
/** FrameReciever class - delegate for AVCaptureSession
*/
@interface AVFFrameReceiver : NSObject
@@ -219,17 +213,8 @@ - (void) captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)videoFrame
fromConnection:(AVCaptureConnection *)connection
{
- lock_frames(_context);
-
- if (_context->current_frame != nil) {
- CFRelease(_context->current_frame);
- }
-
- _context->current_frame = (CMSampleBufferRef)CFRetain(videoFrame);
-
- unlock_frames(_context);
-
- ++_context->frames_captured;
+ CFRetain(videoFrame);
+ CMSimpleQueueEnqueue(_context->video_frames_queue, videoFrame);
}
@end
@@ -263,17 +248,8 @@ - (void) captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)audioFrame
fromConnection:(AVCaptureConnection *)connection
{
- lock_frames(_context);
-
- if (_context->current_audio_frame != nil) {
- CFRelease(_context->current_audio_frame);
- }
-
- _context->current_audio_frame = (CMSampleBufferRef)CFRetain(audioFrame);
-
- unlock_frames(_context);
-
- ++_context->audio_frames_captured;
+ CFRetain(audioFrame);
+ CMSimpleQueueEnqueue(_context->audio_frames_queue, audioFrame);
}
@end
@@ -288,6 +264,30 @@ static void destroy_context(AVFContext* ctx)
[ctx->avf_delegate release];
[ctx->avf_audio_delegate release];
+ CMSampleBufferRef frame;
+
+ if (ctx->video_frames_queue) {
+ frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->video_frames_queue);
+ while (frame) {
+ CFRelease(frame);
+ frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->video_frames_queue);
+ }
+
+ CFRelease(ctx->video_frames_queue);
+ ctx->video_frames_queue = NULL;
+ }
+
+ if (ctx->audio_frames_queue) {
+ frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->audio_frames_queue);
+ while (frame) {
+ CFRelease(frame);
+ frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->audio_frames_queue);
+ }
+
+ CFRelease(ctx->audio_frames_queue);
+ ctx->audio_frames_queue = NULL;
+ }
+
ctx->capture_session = NULL;
ctx->video_output = NULL;
ctx->audio_output = NULL;
@@ -298,12 +298,6 @@ static void destroy_context(AVFContext* ctx)
AudioConverterDispose(ctx->audio_converter);
ctx->audio_converter = NULL;
}
-
- pthread_mutex_destroy(&ctx->frame_lock);
-
- if (ctx->current_frame) {
- CFRelease(ctx->current_frame);
- }
}
static void parse_device_name(AVFormatContext *s)
@@ -631,18 +625,18 @@ static int get_video_config(AVFormatContext *s)
}
// Take stream info from the first frame.
- while (ctx->frames_captured < 1) {
+ while (CMSimpleQueueGetCount(ctx->video_frames_queue) < 1) {
CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.1, YES);
}
- lock_frames(ctx);
+ CMSampleBufferRef frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->video_frames_queue);
ctx->video_stream_index = stream->index;
avpriv_set_pts_info(stream, 64, 1, avf_time_base);
- image_buffer = CMSampleBufferGetImageBuffer(ctx->current_frame);
- block_buffer = CMSampleBufferGetDataBuffer(ctx->current_frame);
+ image_buffer = CMSampleBufferGetImageBuffer(frame);
+ block_buffer = CMSampleBufferGetDataBuffer(frame);
if (image_buffer) {
image_buffer_size = CVImageBufferGetEncodedSize(image_buffer);
@@ -658,10 +652,7 @@ static int get_video_config(AVFormatContext *s)
stream->codecpar->format = ctx->pixel_format;
}
- CFRelease(ctx->current_frame);
- ctx->current_frame = nil;
-
- unlock_frames(ctx);
+ CFRelease(frame);
return 0;
}
@@ -681,27 +672,27 @@ static int get_audio_config(AVFormatContext *s)
}
// Take stream info from the first frame.
- while (ctx->audio_frames_captured < 1) {
+ while (CMSimpleQueueGetCount(ctx->audio_frames_queue) < 1) {
CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.1, YES);
}
- lock_frames(ctx);
+ CMSampleBufferRef frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->audio_frames_queue);
ctx->audio_stream_index = stream->index;
avpriv_set_pts_info(stream, 64, 1, avf_time_base);
- format_desc = CMSampleBufferGetFormatDescription(ctx->current_audio_frame);
+ format_desc = CMSampleBufferGetFormatDescription(frame);
const AudioStreamBasicDescription *input_format =
CMAudioFormatDescriptionGetStreamBasicDescription(format_desc);
if (!input_format) {
- unlock_frames(ctx);
+ CFRelease(frame);
av_log(s, AV_LOG_ERROR, "audio format not available\n");
return 1;
}
if (input_format->mFormatID != kAudioFormatLinearPCM) {
- unlock_frames(ctx);
+ CFRelease(frame);
av_log(s, AV_LOG_ERROR, "only PCM audio format are supported at the
moment\n");
return 1;
}
@@ -781,16 +772,13 @@ static int get_audio_config(AVFormatContext *s)
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 while allocating audio
converter\n");
+ CFRelease(frame);
+ av_log_avfoundation_error("error while creating audio converter",
ret);
return 1;
}
}
- CFRelease(ctx->current_audio_frame);
- ctx->current_audio_frame = nil;
-
- unlock_frames(ctx);
+ CFRelease(frame);
return 0;
}
@@ -808,8 +796,6 @@ static int avf_read_header(AVFormatContext *s)
ctx->num_video_devices = [devices count] + [devices_muxed count];
- pthread_mutex_init(&ctx->frame_lock, NULL);
-
#if !TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
CGGetActiveDisplayList(0, NULL, &num_screens);
#endif
@@ -1010,6 +996,21 @@ static int avf_read_header(AVFormatContext *s)
// Initialize capture session
ctx->capture_session = [[AVCaptureSession alloc] init];
+ OSStatus ret;
+ ret = CMSimpleQueueCreate(kCFAllocatorDefault, MAX_QUEUED_FRAMES,
&ctx->video_frames_queue);
+
+ if (ret != noErr) {
+ av_log_avfoundation_error("error while creating frame queue", ret);
+ goto fail;
+ }
+
+ ret = CMSimpleQueueCreate(kCFAllocatorDefault, MAX_QUEUED_FRAMES,
&ctx->audio_frames_queue);
+
+ if (ret != noErr) {
+ av_log_avfoundation_error("error while creating frame queue", ret);
+ goto fail;
+ }
+
if (video_device && add_video_device(s, video_device)) {
goto fail;
}
@@ -1039,7 +1040,8 @@ static int avf_read_header(AVFormatContext *s)
fail:
[pool release];
destroy_context(ctx);
- return AVERROR(EIO);
+ av_log(s, AV_LOG_ERROR, "Error while opening AVfoundation capture
session\n");
+ return AVERROR_EXTERNAL;
}
static int copy_cvpixelbuffer(AVFormatContext *s,
@@ -1088,38 +1090,35 @@ static int copy_cvpixelbuffer(AVFormatContext *s,
static int avf_read_packet(AVFormatContext *s, AVPacket *pkt)
{
OSStatus ret;
+ int status;
AVFContext* ctx = (AVFContext*)s->priv_data;
do {
- CVImageBufferRef image_buffer;
- CMBlockBufferRef block_buffer;
- lock_frames(ctx);
-
- if (ctx->current_frame != nil) {
- int status;
+ if (1 <= CMSimpleQueueGetCount(ctx->video_frames_queue)) {
int length = 0;
-
- image_buffer = CMSampleBufferGetImageBuffer(ctx->current_frame);
- block_buffer = CMSampleBufferGetDataBuffer(ctx->current_frame);
+ CMSampleBufferRef video_frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->video_frames_queue);
+ CVImageBufferRef image_buffer =
CMSampleBufferGetImageBuffer(video_frame);;
+ CMBlockBufferRef block_buffer =
CMSampleBufferGetDataBuffer(video_frame);
if (image_buffer != nil) {
length = (int)CVPixelBufferGetDataSize(image_buffer);
} else if (block_buffer != nil) {
length = (int)CMBlockBufferGetDataLength(block_buffer);
} else {
- unlock_frames(ctx);
+ CFRelease(video_frame);
return AVERROR(EINVAL);
}
- if (av_new_packet(pkt, length) < 0) {
- unlock_frames(ctx);
- return AVERROR(EIO);
+ status = av_new_packet(pkt, length);
+ if (status < 0) {
+ CFRelease(video_frame);
+ return status;
}
CMItemCount count;
CMSampleTimingInfo timing_info;
- if
(CMSampleBufferGetOutputSampleTimingInfoArray(ctx->current_frame, 1,
&timing_info, &count) == noErr) {
+ if (CMSampleBufferGetOutputSampleTimingInfoArray(video_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);
}
@@ -1133,18 +1132,18 @@ static int avf_read_packet(AVFormatContext *s, AVPacket
*pkt)
status = 0;
ret = CMBlockBufferCopyDataBytes(block_buffer, 0, pkt->size,
pkt->data);
if (ret != kCMBlockBufferNoErr) {
- status = AVERROR(EIO);
+ av_log_avfoundation_error("error while copying buffer
data", ret);
+ status = AVERROR_EXTERNAL;
}
}
- CFRelease(ctx->current_frame);
- ctx->current_frame = nil;
+ CFRelease(video_frame);
if (status < 0) {
- unlock_frames(ctx);
return status;
}
- } else if (ctx->current_audio_frame != nil) {
- CMBlockBufferRef block_buffer =
CMSampleBufferGetDataBuffer(ctx->current_audio_frame);
+ } else if (1 <= CMSimpleQueueGetCount(ctx->audio_frames_queue)) {
+ CMSampleBufferRef audio_frame =
(CMSampleBufferRef)CMSimpleQueueDequeue(ctx->audio_frames_queue);
+ CMBlockBufferRef block_buffer =
CMSampleBufferGetDataBuffer(audio_frame);
size_t input_size = CMBlockBufferGetDataLength(block_buffer);
int buffer_size = input_size / ctx->audio_buffers;
@@ -1170,8 +1169,9 @@ static int avf_read_packet(AVFormatContext *s, AVPacket
*pkt)
if (ret != kCMBlockBufferNoErr) {
av_free(input_buffer);
- unlock_frames(ctx);
- return AVERROR(EIO);
+ CFRelease(audio_frame);
+ av_log_avfoundation_error("error while accessing audio
buffer data", ret);
+ return AVERROR_EXTERNAL;
}
}
@@ -1188,23 +1188,25 @@ static int avf_read_packet(AVFormatContext *s, AVPacket
*pkt)
av_free(input_buffer);
if (ret != noErr) {
- unlock_frames(ctx);
- return AVERROR(EIO);
+ CFRelease(audio_frame);
+ av_log_avfoundation_error("error while converting audio
data", ret);
+ return AVERROR_EXTERNAL;
}
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);
+ CFRelease(audio_frame);
+ av_log_avfoundation_error("error while copying audio
data", ret);
+ return AVERROR_EXTERNAL;
}
}
CMItemCount count;
CMSampleTimingInfo timing_info;
- if
(CMSampleBufferGetOutputSampleTimingInfoArray(ctx->current_audio_frame, 1,
&timing_info, &count) == noErr) {
+ if (CMSampleBufferGetOutputSampleTimingInfoArray(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);
}
@@ -1212,21 +1214,15 @@ static int avf_read_packet(AVFormatContext *s, AVPacket
*pkt)
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);
+ CFRelease(audio_frame);
} else {
pkt->data = NULL;
- unlock_frames(ctx);
if (ctx->observed_quit) {
return AVERROR_EOF;
} else {
return AVERROR(EAGAIN);
}
}
-
- unlock_frames(ctx);
} while (!pkt->data);
return 0;
--
2.32.0 (Apple Git-132)
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